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Winter field peas as green manure before nitrogen-demanding crops
Utilising the pre-crop effect of grain legumes
Components of the pre-crop effectThe pre-crop effect includes two elements: the nitrogen effect and the break crop effect. The nitrogen effect is the provision of nitrogen to the following crop through the nitrogen carried over in the residue from the previous crop. The size of the nitrogen-related effect depends on residue quantity and quality from the legume crop. The break crop effect is due to the reduction in the risk of diseases, pests and weeds in cropping sequences otherwise dominated by another plant family, usually grasses (cereals). These biotic risks are reduced as their life cycles are “broken”. Legumes also improve soil structure and enhance soil microbial processes, which in turn may increase the availability of some nutrients, e.g., phosphorus. Deep rooting in some legumes species such as lupin reduces soil compaction and increases waterholding capacity of soil for the following crop. Phosphorous availability for subsequent crops can also be improved because some legumes are able to mobilise reserves of phosphorus in the soil that are less available to other crops.
Farm-level implicationsGrowth and yield of cereals following legumes is often increased and incidences of pests, diseases and weeds are reduced. In situations where soil mineral nitrogen supply is enhanced by legumes, nitrogen fertilisation can be reduced. This is directly translated into increased revenues and reduced costs for fertilisers and pesticides. In addition, improved quality such as higher protein content can increase the market value of the following cereal crop. Better soil structure caused by tap roots supports higher yields and allows reduced tillage. For instance, no ploughing is needed before the seed bed preparation for the crop following grain legumes such as lupin or soybean. This reduces machinery costs. Quantification and valuation of the effects on crop inputs and outputs are difficult since they are dependent on a range of interacting agronomic and economic variables. Variations in yield effects can be high and current producer prices, costs for fuel, fertilisers and pesticides also largely impact the value of the effect. Additionally, increased revenues and cost reductions are not always realised simultaneously. However, estimations of pre-crop values of grain legumes to subsequent cereals compared to cereal pre-crops allow us to sort the farm-economic relevance of the effects roughly and price scenarios enable us to assess the potential value of the effects in different market situations (Figure 1). The most important effect is the yield increase in the subsequent crop compared with the yield in a sequence without the legume. This translates into increased revenues. Depending on the current market prices, revenues from the first subsequent crop can be several hundred Euros higher as a result of the break crop effect of the legume. Positive effects were found even in second cereals after the break crop. Cost reductions from reduced tillage, reduced nitrogen fertilisation and pesticide savings are also relevant. The effect of the fertiliser savings increases as prices for fertilisers increase, as we are currently seeing in markets. Potential effects through increased quality of following crops can be very variable and below economic relevance. In the context of the individual farm, a simplified calculation of the pre-crop value of grain legumes can support the estimation of potential effects at the farm level - as it was done on the demonstration farms of the network for cultivation and utilisation of field peas and faba beans in Germany (Table 1). The assessment of the pre-crop value is key to getting a more realistic picture of a grain legume’s economic value. Therefore, adequate profitability measures such as expanded gross margins that credit the pre-crop value on subsequent crops to the legume’s gross margin itself or even an economic assessment of whole cropping systems are necessary. A range of experiments, reviews, and surveys of farmers provide estimates of the size of the pre-crop effect of grain legumes. Cereal crops often yield 0.5–1.6 t per ha more after grain legumes than after cereals in Europe (Preissel et al., 2015). However, several aspects need to be taken into account when estimating the effects for a specific farming context. The estimated values differ depending on the reference pre-crop chosen for comparison. Largest effects can be found when legumes are compared to cereal crops as pre-crops. In contrast, other broad-leaved crops can have a pre-crop effect on cereals that is similar to that of legumes. The management of the following crop also influences the magnitude of the pre-crop effect from the preceding crop. Management practices such as tillage, residue treatment, and the application of nitrogen fertiliser impact on the magnitude of the pre-crop effect. The importance of nitrogen carried over from the previous crop is reduced as the nitrogen fertiliser application increases. The yield effect declines from +2.2 t per ha without fertilisation to +1.5 t per ha when 100–200 kg of N fertiliser is applied to the following cereal (Preissel et al., 2015). Therefore, the nitrogen-related effect of the legume is highest in systems with low N fertilisation such as in organic farming. Site and climatic conditions such as soil characteristics, water availability and temperature also greatly influence the pre-crop effect. Differences in mineralisation of organic nitrogen in the pre-crop residues is one reason why there are considerable differences in the nitrogen saving potentials on different sites. The pre-crop effects are likely to be relatively larger on sites with a low yield potential than on sites with a higher yield potential. Besides, the pre-crop effect varies depending on the particular legume species. Legume species such as faba bean have a high-biomass and deep root system. These leave more crop residues with available nitrogen than low-biomass legumes such as lentil. Lastly, the effects of grain legumes as pre-crops depends on the rotations in which they are introduced and are highest in cereal-dominated rotations. The disease and weed-related break crop effects are particularly large in these systems.
Key practice points
- Grain legumes reduce input costs and increase the yield of subsequent crops because of a combination of nitrogen and break crop effects.
- High fertiliser prices increase the relevance of the pre-crop effect.
- Cereal-dominated cropping systems respond most to the pre-crop effect of introducing legumes.
- The increase in yield of the subsequent cereal crop ranges often from 0.5–1.6 t per ha.
- The yield increase from the pre-crop effect declines (from 2.2–1.5 t per ha) with increasing N fertilisation (from 0–200 kg).
- Estimation of the economic value of the pre-crop value is useful in assessing the effect on an individual farm.
- Models such as ROTOR can help in evaluating the pre-crop effect in rotations (see further information).
Further informationSoftware tool ROTOR - download: www.zalf.de/de/forschung_lehre/software_downloads/Documents/oekolandbau/rotor/ROTOR.zip
Intercropping legumes with rapeseed to reduce nitrogen and pesticide use in a 10-year diversified cropping system in Champagne, France
Intercropping legumes with rapeseed to reduce nitrogen inputs and pesticide use and improve profitability
Diversification of cereal-based rotations with soybean as a second crop
Increasing feed production using legume and cereal mixtures as a second crop
Production constraints and opportunities: A Delphi study within the Legume Translated consortium
Growing faba bean and pea in the Nordic region
OutcomeUseful knowledge on cultivating faba bean and pea under Nordic conditions.
Uses of the cropsThe most common grain legumes grown in the Nordic countries are pea (Pisum sativum L.) and faba bean (Vicia faba L.). Both provide a good break crop in the cerealdominant monocultures common in many Nordic countries. There is a growing demand for both species, especially as part of the effort to increase domestic sourcing of raw materials for feed, and increasingly for the plant-protein food industry. Pig and poultry production can make use of both crops as feed instead of imported soybean. In cropping systems, they fix atmospheric nitrogen and their residues provide residual nitrogen for the next crop. They are further valued for other attributes such as their ability to break soilborne disease cycles and improve soil structure.
Choice of cultivarThere are relatively few well-adapted cultivars of these species available to Nordic farmers on account of the short growing season in the region. The key novelty in faba bean breeding is the reduction in vicine-convicine content (favism factors). These two natural chemicals restrict the use of faba bean for some people and in animal feeds. New cultivars have only 5% of the normal vicine-convicine content and are safe for all consumers. For pea, resistance to lodging (standing ability) has long been the main problem for farmers. Most modern cultivars are semi-leafless, meaning that the true leaves have been replaced by tendrils and the stipules are greatly expanded, restoring the photosynthetic area. These cultivars stand up well because the tendrils form a strong network between plants.
Site characteristicsThe opportunities for growing faba bean and pea in this region decline with increasing latitude. However, farmers grow faba bean and pea as far north as latitude 63°N. Common parameters for achieving good yield levels include soil type, pH level, water management and drought susceptibility (Table 1). The margins of pH tolerance are tested by farmers, often at the expense of yield. In soils with high organic content, vegetative growth is favoured so there is a greater risk of lodging and late maturity, but experienced farmers can achieve high yields in this situation.
Waterlogging and droughtWaterlogged soils lack oxygen, so roots suffocate. While faba bean is considered more resistant to waterlogging than other grain legumes, the wet conditions favour the growth and spread of diseases. In drought conditions, plants close their gas-exchange pores, preventing both the loss of water and the uptake of carbon dioxide for photosynthesis. When water is not taken up from the soil, nutrients are also not absorbed. Drought can occur at any time in the growing season and appropriate management depends on its timing. Terminal drought, near the end of grain filling, is typical of Mediterranean climates and uncommon in northern Europe. Transient drought in the middle of the growing season can be managed with irrigation, if the infrastructure is available, and plant breeders seek ways of avoiding it through improved root systems. Drought during seedling establishment in May is common in northern Europe and exceptionally hard to manage, since the roots have had little opportunity to find water in the soil. Pea is less sensitive than faba bean to drought, as shown in both 2018 and 2021, when prolonged mid-summer drought reduced mean faba bean yields far more than those of pea. [caption id="attachment_26668" align="aligncenter" width="1024"] Waterlogged faba bean[/caption]
InoculationBoth legumes form a nitrogen-fixing symbiosis with soil bacteria classified as Rhizobium leguminosarum symbiovar viciae. Different strains of this bacterium can make 5% differencein the amo unt of nitrogen fixed. It is widespread throughout Europe but the population may not be large enough if the field has no history of cultivation of pea, faba bean or its other hosts. Hence, inoculation with a commercial rhizobium preparation is widely recommended in this circumstance. Intercropping legumes with non-legumes usually increases the nitrogen fixation of the legume as the companion takes up the available mineral nitrogen from the soil. To avoid desiccation, the drying out of the bacteria on the seed, the inoculum is applied shortly before planting – no more than a couple of days; see the video “Inoculating grain legumes” under further information. Sowing takes place in early spring, as soon as the soil is sufficiently warm (about 5°C) and dry enough to take the weight of the seeder, which in Finland is usually at the beginning of May. Faba bean has one of the longest growing seasons of Nordic crops, so on most farms it should be the first to be sown. The shorter growing period of peas (approximately 90 days) allows for more flexibility when it comes to the seeding time. Table 2 shows the main sowing requirements of both crops. Deep sowing helps to ensure access to water for the germinating seed, which reduces the effects of early-season drought, and reduces the risk of predation by crows and pigeons. The water requirement is high due to the relatively large seed size. The target populations are lower for faba bean than for pea. Faba bean cultivars adapted to the Nordic region tend to have small seeds, 300–400 g/thousand, but in climates with longer growing seasons, the most productive beans are in the 500–800 g/thousand range and broad beans for food use can be up to 3000 g/thousand. Peas are generally somewhat smaller than the smaller sizes of faba beans.
Soil compaction and removal of stonesSoil compaction is an issue for both faba bean and pea as it reduces their overall plant growth and yield. Good aeration, deep tillage and deep sowing ensure good emergence and root development. Autumn or spring tillage makes it easier to drill the soil during spring. Other farmers manage well with zero tillage and direct drilling, and yields are widely better in zero-tillage systems. Rolling after sowing presses down stones that can interfere with harvesting and rolling helps to prevent contamination with soil when harvesting.
Weed managementFew herbicides are available for use on any grain legume and the crops are sensitive to the residues of herbicides widely used against broad-leaved weeds in previous crops. In practice, this means selecting a field with minimal herbicide residues from preceding crops e.g. cereals. Seedlings of weeds are best controlled before the crop is 5–7 cm in height.
FertilizersThe organic matter content of the soil and its available nutrients determine the amount of fertilizer needed. Fertilizer products that are low in nitrogen are most suitable for faba bean and pea, so the farm can take full advantage of their nitrogen-fixing ability. Although scientific experiments have widely failed to show any benefit of starter nitrogen, many farmers see one, so they apply starter nitrogen fertilizer at 20–40 kg/ha. Phosphorus and potassium fertilization of faba bean and pea is similar to that for cereal cultivation. Potassium, phosphorus and magnesium improve resilience against disease, such as chocolate spot (Botrytis) of faba bean. Micronutrients may also be needed in some soils. For example, molybdenum is essential for nitrogen fixation.
Management during the growing season
Disease controlThere are several diseases affecting faba bean and pea in the region (Table 3). Farmers have many tools with which to prevent the arrival of crop diseases and pests. To prevent disease outbreaks, the recommended minimum interval is 3 years of non-legume crops between successive legumes on the same field. Fungi such as Sclerotinia and Phytophthora can persist 3–5 years in the soil, whereas Aphanomyces root rot of pea survives for up to 10 years. Fungicide treatment of seeds improves the emergence percentage and protects the crop against some early disease symptoms. The use of such fungicides in some countries requires permits and is not widely practiced in the Nordic region. It is important to inspect the crops regularly for diseases and pests in July, during flowering, so any necessary treatment can be applied in a timely manner, according to the principles of integrated management. Downy mildew requires cool growing conditions. It was widespread on faba bean in the cool summer of 2017 in the Nordic and Baltic countries, but is otherwise rare in this region. Rust of both legumes is a disease of warm, humid conditions and arrives late in the growing season in this region when it causes no detectable damage. Chocolate spot disease is almost universally seen as a few spots on faba bean leaves and is not a serious problem until the weather conditions are right, typically 20–22°C with nearly 100% humidity and damp leaf surfaces. In this situation, generally predictable from the weather forecast, the whole plant stand can be killed in 48 hours, so rapid fungicide treatment is vital. [caption id="attachment_26680" align="aligncenter" width="1024"] Chocolate spot at dangerous levels[/caption]
Pest controlIn Finland, both faba bean and pea are prone to attacks from aphids, leaf weevils, pollen beetles and pea moth caterpillars as well as birds. Pea moth (Cydia nigricans) caterpillars eat the developing seeds in the pods of many legume species, but given a choice, they will take pea in preference to faba bean, lupin or lentil. Pea moths are detected using pheromone traps that are normally placed at least a week before flowering starts and examined every second or third day. More than ten moths after two consecutive checks indicates that pest control threshold has been reached. Chemical treatment normally commence around 8–12 days after their peak emergence. Adults of the leaf weevil, Sitona lineatus, cut crescents from the edges of leaves and stipules. It is their larvae that do the damage by consuming the developing root nodules. Pyrethrum is the usual insecticide to control this pest and the intervention needs to be early, as once the eggs are laid on the soil, the damage to the roots cannot be stopped. Both crops have aphids, the pea aphid being Acyrthosiphon pisum and the black bean aphid being Aphis fabae. Weather conditions greatly affect the spread of aphids: heavy rain washes off much of the population and a period of intensely dry weather desiccates them. The pest control threshold is reached when 10% of the plants are infested and the weather forecast indicates that conditions are good for the pest rather than for the plant. Genetic forms of resistance to aphids have not been identified in pea or faba bean, so breeding for resistance is unlikely in the near future. Both aphid species over-winter in hedgerows and woodlands. They spread from random landing points near the edges of the field, so a large field is likely to show less damage than a small one. There is some evidence that early-sown crops are more likely to be found by aphids, but this has to be balanced against the other benefits of early sowing in this region. Seed weevils (Bruchus pisorum on pea and B. rufimanus on faba bean) ruin the seeds for food use and reduce their value for feed. Pea weevils have been present in the Nordic region for decades but the bean weevil is a recent arrival. Control is difficult because the eggs are laid within the flower and after hatching, the larva immediately penetrates the seed, so it is protected from most protection chemicals. Early detection with pheromone traps is vital, to be followed by appropriate treatment as advised by the local agricultural consultant. [caption id="attachment_26688" align="aligncenter" width="514"] Aphids on faba bean[/caption]
LodgingLodging makes the crops very hard to harvest. The strong stem of faba bean makes it more resistant to lodging than pea (Table 4). Rain during seed filling increases the risk of lodging. To prevent pea crops from lodging, companion crops with strong straw, such as oat, barley and wheat, are often used. The target is one cereal stem per pea stem, so the cereal sowing rate is 15–30 kg/ha, because at higher densities the cereal out-competes the legume.
Harvesting and desiccationAs the plants approach harvest readiness, first the pods and later the stems turn straw-coloured (pea) or black (faba bean). Lower pods mature before upper ones and when they start to open, it is a sign that harvesting needs to be done soon. Normally, all leaves have fallen by this time. In this region, faba bean is harvested at a moisture content of 18–20% and pea at 20–25%. In warmer climates, the harvest moisture content is 14–15%. Lower moisture content increases the risk of pod shattering and high moisture content allows seeds to get crushed in the harvester. Although the seed coats are thick, legume seeds are more easily bruised during harvesting than cereal grains, so the combine harvester needs to be set up accordingly. The driving speed and drum speed are low, the fan speed high, the flails and screens open. Green pods are returned to the field by adjusting the top screen as they can cause blockages in the combine and other problems later in the dryer. The straw chopper has a lot of work to do in a faba bean crop, especially when the vegetation is dense, so it may need adjustment to make longer chaff. Since some seeds are moister than others and may start heating and rotting, drying is started quickly but proceeds slowly, often in two stages, as the thickness of the seeds prevents the centre of the seed from drying as quickly as its perimeter. The drying temperature is usually 50–60°C. The target moisture content for faba bean is 14.5% (not below 14%) and for pea 15%.
Catch cropsAfter the harvest, the crop residues are rich in nitrogen. Most farmers leave them in place to nourish the succeeding crop. This comes at the risk of loss by leaching or nitrate or emission of nitrous oxide, a powerful greenhouse gas, so current recommendations include sowing a catch crop, cover crop or winter cereal that will start taking up nitrogen promptly. Faba bean fixes about 80% of its nitrogen needs and pea about 70%. The EU project “Legume Futures” estimated that faba bean added about 24 kg of fixed nitrogen per tonne of harvested beans and that pea added about 6 kg. This helps to reduce the need for nitrogen fertilization of the next crop.
Pre-crop effectThe pre-crop effect of legumes consists of more than just nitrogen. The activity of the nitrogenfixing bacteria supports other beneficial soil microorganisms. The nitrogen-rich residues help maintain the populations of larger soil fauna such as earthworms. A grass-free legume crop allows some soil-borne pathogens of maincrop cereals to die, so the following cereal grows better. [caption id="attachment_26692" align="aligncenter" width="684"] Harvest-ready faba bean[/caption]
Key practice pointsThe decision to grow peas or faba beans can be based on some guiding questions (nonexhaustive):
- Is sowing time an issue? The optimal time for sowing faba bean is very early in the growing season. This poses challenges if the weather does not permit early sowing. Pea can be sown a few days later.
- Are you worried about waterlogging? Faba bean is more tolerant.
- Are you worried about risk of drought? Pea shows more tolerance.
- Do you want a grain legume that is less prone to lodging? In that case, faba bean stands better than pea.
- Are you searching to diversify your crop rotation? Both crops provide nitrogen for the next crop and disease control.
Further informationStoddard, F. L., 2017. Grain Legumes: an overview. In: Murphy-Bokern, D., Stoddard, F. L. & Watson, C. A. (Eds.). Legumes in Cropping Systems. CABI, Wallingford, pp. 70–87. Schauman, C., Leinonen, P., Mäki, S., Stoddard, F. L., Lindström, K., 2021. Inoculating grain legumes. University of Helsinki. Legumes Translated video.
Continental and global effects
An application of life-cycle assessment (LCA) to legume cropping
Effects of legume crops on biodiversity
The role of legume production and use in European agri food systems
Growing soybean in north-western Europe
The potential for adapting soybean adaptation to north-western EuropeThe cultivation of soybean in Europe has increased considerably aided by cultivars that mature early. Matching cultivar to location combined with optimal agronomic practices (sowing date, seed rate, and distance between rows) is fundamental to viable and profitable soybean production in any environment. Soybean is a warm season legume, with growth interrupted when temperature drop below 8°C. It is also a short-day crop. This means that flower development is suppressed in the longday conditions of summer in most of Europe above 45°N, unless the cultivar is day-neutral. The crop requires a sufficient number of warm days to mature, usually expressed by growing degree-days (GDD), using 10°C as the base temperature. Crop heat units (CHU) are also used. The calculation of CHU uses 10°C and 4.4°C as the daytime and night-time base temperatures respectively. The minimum reported values for soybean are 933–1,041 GDD (base 10°C) and about 2,300 CHU. This requirement for heat and for day neutral cultivars makes the production of soybean above about 52°N (approximately the line from Cork in Ireland to London across to Berlin) particularly challenging, especially in north-west Europe where long summer days are combined with relative cool maritime conditions, such as in Ireland. The first requirement for cultivation under the conditions described above is to use day length neutral cultivars. This is met by cultivars classified in the zero maturity groups (0, 00, 000, and 0000). The second requirement is rapid progress through all development stages to reach maturity in September under relatively cool conditions. The cultivars that most meet this requirement are commonly classified as 000 cultivars, with a few even earlier than these (0000).
The soybean field trials at Oak Park research farm in Carlow, IrelandFifteen varieties of soybeans (Table 1) were selected in consultation with the Soybean Network of the Legumes Translated project, soybean breeders and merchandisers. Seed was inoculated with rhizobium (LegumeFix, Legume technology, UK), and sown at a depth of 3–4 cm, using a Haldrup planter, on 22 May 2019 and on 7 May 2020. The total plot area was 18 m2 (1.2 m x 15 m). Each cultivar was tested using two row widths: 40 and 60 cm. A randomised block design was used with 4 replicates. Details of the weather from March to October 2020 are presented in Figure 1. In the 2019 season, white sprouts of the sprouting soybean in the field were observed about 3 weeks after sowing, without the cotyledons. Only one seedling has survived beyond the cotyledon stage. A flock of pigeons that earlier in the season grazed on an adjacent oilseed rape field may have been responsible for the unsuccessful trial. In the 2020 season, emergence was observed from 20 May on. The emergence rate was low and not uniform, probably related to the cold period observed just after sowing (minimum air temperature from -0.9 to 5.7°C and soil temperature from 12 to 15°C, between the 10th and the 15th of May) and the relative low air temperature throughout the month of May (Figure 1). Some bird damage was also observed. Flowering was observed in mid-August and pod development and seed filling from beginning of September on (Figure 2). Earlier flowering of cultivars with petals that not fully unfold may have escaped the untrained eye. In the cultivars that are not day neutral, such as the ones in maturity groups I and II, flower initiation may have been inhibited by the long summer days and delayed until nights lengthened to a cultivar-specific minimum. Although plants begin maturing between the months of September and October with hardening pods, there were still significant foliage in mid-October. 2,390 CHU were accumulated in the period between sowing and 30 September in 2020. The weed-burden was high, related to the poor plant establishment resulting in poor plant competition throughout the season but also due to a lack of suitable herbicides registered in Ireland for weed control in soybean. Soybean cultivation in Carlow for grain production may not be feasible as CHU only marginally exceed 2,300 (growing season mean of 2,383 (1 May–30 September), over the period of 2005-2021), considered as the minimum accumulated units for a feasible soybean crop. Lower CHU values are accumulated if the growing period is shortened due to later sowing and earlier harvest, as presented in Figure 3.
Relevance for other parts of north-western EuropeConsidering the experience of other European countries such as Germany where soybean is cultivated, the potential growing season for soybean in Ireland and other north-western European countries lies between beginning of May and the end of September. However, the climate in Germany allows soybean sowing from beginning of May on when soil temperature reaches 10°C and is rising steadily through May. The beginning of May is still quite cool over most of Ireland. Consequently, consistent and rising soil temperatures above 8–12ºC, required for establishment, are reached only in the second half of May. Low early season temperatures reduce yield. On the other end of the growing season, the risk of rainfall in Ireland increases as autumn progresses. Harvesting in September rather than October reduces the risk of excessive moisture in the crop and grain. As a consequence, the growing season for soybean in certain regions in Ireland would most probably be shorter compared to in Germany. This reduces the period during which heat is accumulated by 200-300 CHU, depending on the year (Figure 3). Based on these observations, the feasibility of soybean production could be assessed in the most promising locations. Only the earliest cultivars, usually classified in maturity groups 000 and 0000, are potentially suitable for Irish conditions. Based on authors’ experience, about 2,600 CHU, or about 1150 GDD (base 10°C), are required from emergence to harvest. Based solely on CHU, soybean production may be feasible in areas of County Cork, such as around Cloyne, Linsaley, where calculated CHU were close to those observed in German soybean producing areas such as in Tailfingen (altitude 450 m) and Ochsenhausen (altitude 625 m) in Baden-Württemberg (Figure 3). In the other locations considered, the CHU were lower than the minimum required in at least 3 out of 10 years, and never surpassed 2,500. However, considering that more daylength may substitute some low temperature, it might be interesting to test soybean cultivation for several years also at those places and evaluate if this effect is sufficient for a sustainable production. Ideally, pea and/or faba bean will also be sown to get an idea about the relative performance of those 3 grain legumes at each site.
Key practice points
- We did not succeed in growing soybean for grain in Carlow, Ireland. The crop did not mature in time to avoid wet conditions and high grain moisture at harvest.
- Research results from Ireland do not support growing of soybean until more suitable cultivars are proven. Further studies are needed in Irish conditions with earlier day neutral cultivars (maturity groups 000 - 0000) in regions that accumulate more CHU over the growing season.
- Sowing and harvesting dates need careful consideration to meet crop requirements, namely a soil temperature of 8–12ºC at sowing followed by a consistent increase in soil temperature, and dry conditions at harvest, with implications in the length of the growing season.
- Herbicides are not available locally, although some of plant protection products registered for other purposes are suitable but do not carry clearance for use in Ireland. Local availability will remain a problem until sufficient soybean areas are grown.
- Bird damage in areas with known high bird density, in particular pigeons and crows, can significantly decrease the plant population in the field. In those areas, agronomic practices, such as adjusting time of sowing to enable rapid establishment in periods with lower bird activity, need consideration.
Guide for farms to plan small scale soya bean processing equipment
Guide for assessing the protein quality in soya feed products
Recommendations for using soya-based feedstuffs in pig husbandry
Unprocessed soya beans low in trypsin inhibitors in organic pig fattening diets
Alternatives to soya bean for fattening broilers
Using near-infrared tools to monitor heat damage in soya bean products
Foraging of organic finishing pigs on protein-rich fodder
Utilisation of waste heat from biogas plants for drying fine‐grained legumes
Recommendations for using soy-based feedstuffs for poultry production
Sprouted wheat and vetch seeds as a green feed for poultry
Actor group’s knowledge and insights into constraints and opportunities
Sclerotina stem rot in soybean
DescriptionIt is important to understand the cosmopolitan nature of Sclerotinia sclerotiorum. Sclerotinia is a soil-borne rotational disease hosted by a wide range of broad-leaved crops. In addition to soybean, hosts include oilseed rape, sunflower, pea, faba bean and even potato. Fruiting bodies called sclerotia form in the stems and these dark resting bodies carry the disease in the soil from season to season. There is no host specialisation and so it transmits easily between species within the rotation. Where sclerotia are present in soil, outbreaks depend on weather conditions whether sclerotia are ‘germinating’ to produce fruiting bodies (apothecia). Plant infection starts during flowering stages. Early symptoms are visible in R2 stages and later. Infection first interrupts the flow of water in the stem. After infection, upper leaves lose turgor, wilt and mycelium spreads throughout the plant. At first, the leaves are grey to green in colour, later they become darker brown. Wilted leaves remain attached and infected plants are then easily detected. Stem lesions develop 7–14 days before foliar symptoms are visible. Water-soaked lesions spread rapidly and encircle the stem. White cottony mycelium grows through rotten plant parts. With early infections, the pods dry off completely before the grain filling phase starts, and as a result, such plants produce no grain. If the grains have been formed in the pods before the disease strikes, they remain small. The pods may also be directly infected and become wet and soft with white mycelia growing out. Sometimes they rot completely, and sclerotia form instead seeds. Moisture is very important for the onset and spread of soybean white mould. There are no known cultivar resistances, similarly to other white mould plant hosts (over 400 plant species). However, there are differences in tolerance between cultivars. Late-maturing genotypes are more susceptible to yield loss than early-maturing ones. Also, short-season cultivars are not physiologically resistant but they may avoid the pathogen attack. [caption id="attachment_24583" align="aligncenter" width="1024"] Life cycle of Sclerotinia sclerotiorum[/caption]
Key practice points
- Crop rotation is an important management practice. Susceptible crops should not be grown more often than in one out of four years (a three year gap between susceptible species).
- Biological soil fungicides based on Coniothyrium minitans (CONTANS WG®) are available in some countries. These are applied to residues of infected crops after harvest to reduce the number of viable sclerotia.
- Warm humid conditions promote the development of apothecia on sclerotia. Dense plant stands and irrigation, especially at flowering, promote infection if fruiting sclerotia are present in the soil.
- Sclerotia can germinate if moisture is present, resulting in seed decay in storage.
- Soybean seed should be free of the fungus sclerotia which can be achieved by high-quality seed.
Heat treatment and dehulling effects on feed value of faba beans
Why farmers grow lupin
The survey and respondentsAn online survey with conventional and organic farmers who cultivated lupin was conducted across Germany within the ‘Demonstration Network for Cultivation and Utilisation of Lupin’ between October and December 2019. In total, 67 farmers responded. Most farmers were from the states Brandenburg, Hesse, North Rhine-Westphalian, Lower Saxony, Bavaria and Saxony-Anhalt with 7-12 responses each. Since lupin is mainly produced on sandy soils with low soil pH in north-eastern Germany, the sample included farmers from this region and also farmers from western and southern areas where lupin production is novel. Conventional farmers were the largest group with a share of 64% (43), 36% (24) were organic farmers.
Lupin production and useMost of the conventional farmers (80%) reported producing only narrow-leafed lupin (Lupinus angustifolius L.). White lupin (Lupinus albus L.) was grown by 10%. Both species were grown by 7%. Many organic farmers (54%) reported producing only narrow-leafed lupin, while 25% produced white lupin. Both were grown by 13%. Only a very few farmers produced the yellow lupin (Lupinus luteus L.). This distribution reflects the general dominance of narrow-leafed lupin in Germany with 10 registered cultivars in 2022. Due to the disease anthracnose, caused by Colletotrichum lupini (Bondar), white and yellow lupin cropping stopped around 1995, and only the tolerant cultivar of white lupin is now grown (4 registered cultivars in 2022). The majority (54%) of the conventional farmers produced lupin for on-farm use only while 18% produced lupin as a cash crop only and 28% for both. This split for organic farms was even (32%, 36% and 32%, respectively). Lupin sold from conventional farms was mostly for feed (89%) and less often for food (17%) or seed (11%). Compared to the conventional farmers, more organic famers sold their lupin for food (47%) which reflects the higher market share for organic lupin-based food products e.g., meat replacements, meal, coffee, drinks. The larger share of organic lupin was sold for feed (67%).
Motivation for lupin productionThe most stated motivation of conventional farmers was to produce domestic protein feed (60%). Steadily increasing soybean prices support this motive. Agronomic motives, such as crop diversification and enhancing crop rotations were cited by 40%. Other motives arise from financial incentives from the Common Agricultural Policy and personal interest in the cultivation of lupin. Some farmers referred to drought tolerance of lupin and benefits for soil fertility as motives to grow the crop. Enhancing crop rotations and crop diversification was most important for organic farmers (48%). This reflects the crucial agronomic role legumes have in supplying reactive nitrogen on organic farming. Organic farmers also stressed domestic protein feed (42%).
Challenges in lupin productionThe main challenges perceived in lupin production were very similar from conventional and organic farmers. Drought is regarded as the greatest challenge by both groups. This is likely to be a consequence of the extreme weather conditions in 2018/2019. Weed infestation, particularly late infestation, is seen as another major challenge. This reflects the poor competitiveness against weeds and the limited options for weed control especially in the late growing phase. Other unfavourable weather conditions were seen as a medium issue by about50% of the conventional as well as organic farmers. More organic farmers (41%) than conventional farmers (16%) perceived anthracnose as a medium or major challenge for lupin cultivation. A similar picture but on a lower level was shown for an infestation risk with the lupin weevil (Sitona gressorius F. and Sitona griseus F.) – 24% of organic farmers named it as a challenge and 15% of conventional farmers. Other pests and diseases were only seen as a challenge by individual farmers.
Further challenges farmers perceived with lupin cultivation could also be derived from farmers’ assessment of lupin yield and yield stability. Almost half of the conventional farmers assessed yield as poor and the other half as medium (48% and 52%, respectively). Organic farmers assessed lupin yield even worse with 65% describing the yield as poor and 35% as medium. Yield stability was also rated negatively by 63% of conventional farmers and by 67% of organic farmers. A question comparing lupin with other legumes also stressed the yield issues perceived by farmers: over 70% of conventional and organic farmers assessed lupin yield in comparison to other grain legume yields as lower.[caption id="attachment_24520" align="aligncenter" width="1024"] Pods of white lupin grown in a field experiment[/caption]
Reasons to stop lupin cultivationFarmers were asked whether they plan to stop or already have stopped lupin production. The majority of conventional and organic farmers stated the intention to continue production, 53% and 62% respectively. However, the other farmers which represent a considerable share, planned to stop or already have stopped lupin cultivation. The major reason to stop cultivation was related to the low yield reported by conventional (50%) and organic farmers (30%). This emphasis on low yields can most likely be traced back to very low yields in 2018 (national average of 0.95 t/ha) and 2019 (1.22 t/ha) which were lower than the national yield averages of 1.56 t/ha from 2011-2021. Organic farmers named also weed infestation (30%) and the increase of the lupin weevil (20%) as important reasons. The lack of pesticides was by 14% of conventional farmers mentioned as a reason for stopping lupin production. Missing financial incentives were also named by 14% of conventional farmers (there is no specific support programme for legumes in some German federal states). Individual conventional and organic farmers named a range of other reasons such as a poor availability and high costs of seed, high alkaloid contents, anthracnose, a limited farm area, poor gross margins, damage from wild animals esp. from birds, uneven ripening, pod shattering, and the ban of cultivation in water protection zones. While many farmers from this survey planned or already had stopped growing lupin, other farmers who were not part of the survey sample started to grow the crop (we only asked lupin growing farmers). [caption id="attachment_24512" align="aligncenter" width="814"] Figure 1. Lupin harvested area and production in Germany in 2011-2021[/caption]
Changes needed to increase lupin cultivationWhen asked about changes that farmers perceive as necessary to increase lupin cultivation, most conventional farmers ranked the registration of certain pesticides high (72%). Second came financial incentives for protein crops (64%) followed by drought tolerant cultivars (42%) and higher producer prices (41%). Easier distribution channels and disease tolerant cultivars were seen as highly relevant by 22% and 18% of the respondents, respectively and only a few individual farmers perceived new agronomic cultivation techniques, improved mechanical weed management and solutions for controlling the lupin weevil as highly necessary. Organic farmers also perceived disease tolerant cultivars and higher prices (19%) as important conditions for increasing lupin cultivation. Moreover, financial incentives and drought tolerant cultivars were seen as relevant by 16% of the respondents. Similarly to the results from the conventional farmers, few organic farmers stated a high need for new cultivation techniques (13%) and solutions for lupin weevil (6%). Beyond the farm level, farmers saw the greatest potential for inducing change in plant breeding, with 62% of conventional farmers and 75% of organic farmers. Marketing, processing and research were ranked with a high potential by a relatively similar share of conventional farmers with 42%, 38% and 34%, respectively. For half of the organic farmers research had a high potential for change and only few saw this potential in processing (20%) and even less in marketing (7%). [caption id="attachment_24516" align="aligncenter" width="1024"] Figure 2. Proportion (%) of conventional farmers citing different constraints as major and medium problems. Responses were given on a three-point response scale: major problem, medium problem, no problem (n=number of farmers who responded).[/caption]
ConclusionThe survey results present some key issues that farmers perceive for lupin production. Lupin is cultivated particularly for producing a domestic protein feed and due to its rotational benefits. Problems in lupin cultivation are especially associated with yield, tolerance to drought, and competition with weed which also caused farmers’ decision to stop lupin cultivation. Farmers demand cultivars that can deal better with extreme weather and have a higher tolerance against diseases. Action and progress in breeding is therefore perceived as highly relevant. Further factors named by farmers were economic determinants. Financial incentives are relevant to secure a profitable production and also an increase in producer prices were requested by farmers. The survey was conducted after two very dry years with low yields for lupin and other crops. In 2020 and especially 2021, lupin production increased again due to an increasing use of domestic grain legumes for feed and food, the farmer`s interest in growing lupin in regions other than the traditional ones, and the availability of new cultivars, especially white lupin. White lupin can achieve higher yields than narrow-leafed lupin on good soils. Since weather conditions were more favourable in recent years, average yields and harvested production increased. [caption id="attachment_24524" align="aligncenter" width="1024"] Figure 3. Proportion (%) of organic farmers citing different constraints as major and medium problems. Responses were given on a three-point response scale: major problem, medium problem, no problem (n=number of farmers who responded).[/caption]
Key practice points
- Lupin is mainly used for protein feed which is also the strongest motivation for production.
- Low yield, susceptibility to drought and competition with weeds are regarded as constraints.
- Breeding efforts for drought and disease tolerant cultivars are requested.
- Financial incentives and higher producer prices are needed.
Forage legumes for a cool climate
Protein from alternative foragesIncreasing on-farm plant protein production addresses emerging consumer expectations. Producing more high-protein forage reduces reliance on imported protein sources. This reduces the carbon footprint of the feed and reduces the impact of fluctuations in the price of imported feeds, e.g., soya from South America.
- Demonstration plots of alternative forages were grown and harvested in a cool wet temperate climate in Scotland to support discussion with farmers and industry stakeholders.
- Plots were sown in early May and harvested in early August.
- Red clover, a red clover/grass mixture, lupin and a lupin/barley mixture, forage pea, a forage pea/barley mixture and crimson clover were grown in plots (3 m x 10 m) and compared with a perennial ryegrass/white clover mixture.
- Initial measurements of dry matter (DM) showed that the pea/barley mixture produced 8 t/ha, the lupin/barley mixture provided 7.3 t/ha, compared to the ryegrass/white clover at 3.8 t/ha.
- The red clover mixture had the highest crude protein content (17.7%) compared to the grass/white clover (16.9%) and pea (16.1%).
- Metabolisable energy (ME) level was highest for the pea and the grass white clover (10.5 MJ/kg DM) while the red clover (10.3 g/kg DM), crimson clover (10.2 MJ/kg DM) and lupin (10.2 MJ/kg DM) were very similar.
Silage qualitySub-samples of the fresh cut material were compressed into 3 litre plastic air-tight containers and ensiled for 5 weeks. These were then analysed for feed quality.
- The silage analysis showed the pea, pea/barley and the lupin/barley mixtures gave the greater DM contents (g/kg).
- The crude protein content of the lupin (19.2%) and red clover mixture (19.6%) were most similar to the ryegrass/white clover (20.8%).
- The protein content of the crimson and red clover, at 18%, were close to the lupin (19.2%) and red clover mixture (19.6%).
- The ME content of the lupin provided just over 10 MJ of ME/kg DM compared to the grass and white clover that provided 11 MJ of ME/kg DM.
- The barley in pea/barley and the lupin/barley mixtures increased the metabolisable energy of the silages.
Key practice points
- Alternative forage crops can be grown successfully in a cool wet temperate climate.
- Forage yield, protein content and metabolisable energy levels can be maintained with most of the alternative crops.
- The grass/clover and clover swards are harvested several times through the growing season.
- The legumes fix nitrogen that is available to subsequent crops. This has been estimated to be 150 to 250 kg N/ha for red clover compared to 80 to 100 kg N/ha for white clover.
The bean seed beetle in faba bean
The lifecycleAn understanding of the lifecycle is the foundation of control strategies and risk assessments. The beetle has one generation per year. Adults hibernate overwinter in leaf litter and under bark before emerging in April/May. Diapausing adults leave overwintering sites to colonise crops when spring temperatures reach 15°C. Females lay eggs on the outside of developing pods, particularly the lower pods from the earliest flowers. Hatched larvae bore through pod walls and develop within the seed. This concealed position in the seed makes them difficult to control with the insecticides that are currently available. Consequently, the adults are the main target of current control attempts. When fully grown, larvae pupate and young adult beetles emerge around harvest time, leaving a round hole in the bean. These holes are the main source of damage to the crop. Some adults stay within the seed and emerge in store, but there is no subsequent infestation of stored beans.
Damage and thresholdsInfestation damages the seed. The weight of individual seeds is reduced by the feeding of the developing larvae within the seed, the nutritional value decreases, and the holes in the seed greatly reduce the quality of the seed. Seed with holes is devalued or rejected due to strict quality standards in both the food (2%) and feed markets (10%). In crops grown for seed multiplication, infestation reduces seed germination and vigour. Furthermore, the presence of live adult beetles in the grain bulk affects access to domestic and international markets.
ControlPeak daily temperature is a reliable indicator of the risk of the pest doing damage. Two consecutive days of sunny weather at the time of first pod setting with maximum temperatures above 20°C is an indicator of risk. Pyrethroid insecticides are typically sprayed during the flowering and first pod setting stages targeting adults before egg laying. However, successful control depends on overcoming numerous challenges:
- Active substances and number of treatments are limited in the EU.
- Treatment must target the adults and reduce egg laying.
- Control of larvae as they hatch from eggs is difficult because they penetrate the pod immediately beneath the egg case.
- The dense crop canopy can reduce the efficiency of spraying by preventing a proper penetration onto the target plant-organs. Research suggests that angled nozzles gives better control than conventional flat fan nozzles.
Bean seed beetle is an emerging pest of faba bean crops in IrelandSamples of grain from 48 commercial faba bean crops grown across Ireland in 2018-2020 were assessed by Teagasc for damage associated with bean weevils (holes were adults emerged) to ascertain whether this emerging pest is reaching economically significant levels in Ireland when the crop to be sold for human consumption. The majority of crops (69%) had no seed damage. 17% were damaged with less than 2% of seed affected, 6.3% presented seed damage between 2-5%, and 8.3% presented more than 5% of seed damaged.
Key practice points
- There is no threshold for beetle numbers in the crop, however the presence of the pest in the crop should be established prior to insecticide application. This can be done by examining flowers, either by opening the flowers to expose the beetles, or by tapping out the flower heads onto a plastic tray.
- Insecticide applications should take place only when max. daily temperature has reached/exceeded 20°C for two days in a row, and only when the crop has reached the first pod formation stage. Egg laying begins when temperature reaches this threshold, and beetles lay eggs only on pods.
- Insecticides should be used when beneficial insects are not foraging in the crop. As such, applications should take place late in the evening, very early in the morning or at night time.
- Use angled nozzles for applying insecticides.
- More reliable integrated pest management options for this pest are needed.
Further informationPGRO, 2021 CB2104 - CROP UPDATE 4 - 28th May 2021 www.pgro.org/cb2104/ Ward, R.L. 2011 Control of bruchid beetle on broad beans, PGRO. www.pgro.org/downloads/Controlofbruchidbeetleonbroadbeans.pdf
Red clover silage
Chemical compositionData in Table 1 show the important differences between typical red clover and perennial ryegrass silages based on observations made in the United Kingdom. The protein content of red clover is 35% higher than that of ryegrass and this allows formulation of diets using less grain-protein concentrates, such as soybean meal. The protein in red clover is concentrated in the delicate leaf structures and so care must be taken to avoid ‘leaf shatter’ during wilting and harvesting. Whilst thorough wilting and fine ‘precision-chop’ harvesting of red clover may promote better fermentation, there is a risk of losing some of the valuable protein through ‘leaf shatter’ creating fine particles that are not picked up in the field. The production of baled silage involves less handling and chopping of herbage. This reduces the risk of ‘leaf shatter’ protein losses. The lower water-soluble carbohydrate (WSC) content and higher buffering capacity of red clover makes it more difficult to ensile and this problem is exacerbated by lower levels of epiphytic (silage-making) bacteria on red clover herbage. These risks can be managed by field wilting of crops, taking the risk of shatter losses into account, and applying silage additives (acids, inoculants, or molasses) to improve fermentation. Nonetheless, red clover silages typically have higher pH, higher butyric acid and higher ammonia-N contents than grass silage. Red clover silages have a dark colour. A dark colour is often associated with poor primary and secondary fermentation of grass silages. However, in red clover silage, this dark colour is the result of the action of the enzyme polyphenol oxidase (PPO) which releases quinones. These bind with protein in a dark-coloured complex (similar to the browning of exposed apple tissue). The action of PPO is beneficial for the nutritional value of red clover silages. It reduces the rumen degradability and improves the utilisation of protein. [caption id="attachment_24285" align="aligncenter" width="500"] Colour change associated with the action of polyphenol oxidase in red clover juice (in comparison with grass juice). Photo courtesy of F Minchin and A Winters, IGER.[/caption]
Digestibility and animal responsesMany studies show that feeding red clover silage increases performance in dairy cows, growing steers, ewes in late pregnancy and finishing lambs. Most of this benefit is the consequence of the higher intake characteristics of red clover silage. The long tough fibres of grasses tend to be retained in the rumen, whilst the reticular vein structures of legumes rapidly break down into small particles. The higher rates of fermentation and more rapid particle breakdown of red clover silage result in higher intakes and milk production across a series of studies (Table 1) with concentrates offered at relatively low levels (4-8 kg/day). This good performance is not predicted by standard assessments of silage quality. The lower digestibility, poorer fermentation characteristics and unattractive appearance (dark colouration) suggest that red clover silage would not be a good feed for high-producing ruminants. The digestibility of mature red clover declines less rapidly with advancing maturity than in grasses. Red clover is especially suited to low-input systems with infrequent cutting. One further aspect of forage composition that has caused some concern with red clover is its content of isoflavones (phyto-oestrogens). It is known that these can disrupt oestrus in sheep grazing red clover, but there is no evidence for negative effects in cattle. Conception rates were even higher in cows consuming red clover silage in two studies.
Key practice points
- Red clover silage feeding value may be better than expected on the basis of digestibility, appearance and fermentation characteristics.
- Higher protein content and protection of some protein from rumen degradation through the action of PPO will reduce requirements for protein concentrates in dairy and beef rations.
- When using red clover silage, plan for higher intakes than for grass silages.
There is a grain legume for every field
OutcomeThe main outcome is the identification of a suitable grain legume species for a given farming situation or field. Selecting the right kind of legume crop can affect the yield potential.
Length and warmth of growing seasonThe first thing to consider is whether the cultivated legume can reach maturity in the growing season at the site. The shorter the growing season, the less choice. Of the cool-season legumes, pea is grown the furthest north, followed by narrow-leafed lupin and faba bean. Looking further south, yellow lupin, lentil, chickpea and white lupin are added to the list. All of these species will tolerate cold soils at sowing and mild frosts during early growth. They are less tolerant of high temperatures, above 27°C, than the warm-season legumes. Soybean and common bean are the best-known warm-season grain legumes. Some soybean cultivars will tolerate a degree or two of frost. Generally, these species stop active growth when temperatures fall below 10°C. Hence, the northern limit for reliable production of soybean is currently around the southern edge of the Baltic Sea. [caption id="attachment_24310" align="aligncenter" width="1024"] Peas[/caption]
Soil texture and pH levelsThe next thing to consider relates to the growing site’s soil texture and pH. Unlike the small grain cereals such as wheat, barley, oat and rye, the cool-season legumes, especially faba bean and lupins, are selective about what soil type they grow on best. For example, if the soil is sandy it is likely to have a low pH (acid) and lupins are the best choice for it. The three species (blue or narrow-leafed, yellow and white lupin) can be grown on soils with pH as low as 4.5. Pea, chickpea and lentil are at their best on fields with intermediate soil texture and a pH between 5.5 and 7. Faba bean is the most suitable legume for heavier clay soils with a neutral to alkaline pH of 6 to 7.5 or even 8. Soybean is less sensitive to soil type and the optimal pH level is between 6.3 and 6.5. [caption id="attachment_24314" align="aligncenter" width="1024"] Faba bean grown in clay soil[/caption]
Lentil and lupins prefer free-draining soils and at the end of the season, need to dry out in order to mature. Narrow-leafed lupin is exceptionally deep-rooting with a tap root that can grow as fast as 2.5 cm per day, so it can reach deep water and nutrients. Its roots have been traced to 2.5 m depth in sandy soils in Western Australia.Soil compaction and waterlogging are severe problems for grain legumes. If your soil is susceptible to waterlogging, it is worth considering amendment or drainage. Faba bean survives waterlogging better than most of the other legumes, but it does not thrive in such conditions. Mid-season drought disrupts the growth of all the legumes. They stop flowering prematurely, which greatly reduces yield potential. Plentiful organic matter in the soil helps in both aeration and water retention. Later drought impedes seed filling, but terminal drought can be useful when it stops the indeterminate growth of the plant and promotes its senescence and maturity.
Length of dayMost cool-season grain legumes are considered to be day length neutral. In other words, their flowering does not depend on the day length being longer or shorter than a certain value. In contrast, flowering of soybean is suppressed by long days and there is genetic variation in response to day length. In practice, only day-neutral cultivars can be grown reliably north of about 45°N. The day-neutral cultivars result in extraordinary flexibility in soybean. Some farmers have succeeded in growing soybean at 61°N in Finland. Growing legumes is often called “challenging” or “demanding”, but it would be better to consider them as “giving” or “rewarding”. They need a little more attention than spring-sown cereals, especially when growing them the first few time(s), so one can expect to make a few mistakes along the way. Their diseases, pests and stress symptoms look a little different from those of the cereals or oilseeds. By giving them attention and learning their needs, they will repay with high yields and quality. Ignore them and they fail. Where possible, it is wise to sow a catch, cover or winter crop after the grain legume in order to capture its residual fixed nitrogen. [caption id="attachment_24322" align="aligncenter" width="1024"] Waterlogged faba bean in southern Finland. Although stunted, the plants are surviving and flowering.[/caption]
Key practice points
- Identifying the right legume crop for your field is dependent on its pH levels and soil texture along with the length of the growing season.
- Good soil conditions are as important for grain legumes as for other crops. Drainage is especially important for lupins and lentil while adequate moisture is particularly important for faba bean.
Moldovan soybean varieties testing in the condition of North Bulgaria
Dehulled grain legumes for food
Goal of dehullingIs there a customer requirement for dehulling? Is there a strong market for dehulled seeds for food products and processing? If the answer is yes to any of the questions, then dehulling is something to consider. The main processing goal is to remove the seedcoat or ‘hull’ of the grain legume seed. The dehulled seeds usually split into two, each half being a whole cotyledon or seed-leaf, and the product is often called “splits”. The splits are an attractive yellow, green or red, depending on the cultivar and its pigments. The hulls are 90% lignocellulose, i.e., insoluble dietary fibre, but the cotyledons have plenty of dietary fibre so the loss is not important in the food chain. The other important component of the hulls is tannins that have both positive and negative effects on the product. Tannins are useful antioxidants in the human diet and they add a distinctive flavour, but they are coloured, so they are not desirable in many wet processes, such as protein isolation or making tofu, where additional colours and flavours should be minimized. They cross-link with raw proteins and precipitate them, which is also enabled in a wet process. In a dry milling process such as flour production or dry fractionation, the hull particles form dark flecks in the light-coloured mass of flour. Dehulled beans have a higher protein content than whole beans because of the low protein content of the hull. The hull slows water intake into the intact seed, so a dehulled seed cooks more quickly. The hull keeps the seed in shape during cooking, whereas a dehulled split easily becomes a puree: both are desirable depending on circumstances. Dehulling usually takes a small portion of the cotyledons with the hulls. The value of the fraction is, however, low and its particles are often dust-sized so its use is restricted.
The dehulling techniqueTraditional dehulling methods involve thorough drying of the seeds. This is followed by rubbing or pounding with a simple mortar and pestle. In larger commercial units, abrasion is applied, using emery-coated rollers made from silicon carbide. Millstones are typically made of two burrstones with farrows or grooves. The gap between the stones is adjusted to remove the hull with minimal damage to the cotyledons. Uniformity of seed size is clearly important. The brittleness of the seeds needs to be taken into consideration as seed breakage is an issue regardless of the machinery used. Newly harvested beans are harder to process if their moisture content is high. Drying to a moisture content under 14%, often around 12%, is usually needed before dehulling. Large seeds are often more economic to dehull than small ones because their lower surface to volume ratio means that losses are lower. This is considered good for the process as the machine adjustments can be kept the same. Shrivelled seeds do not dehull well because the wrinkles prevent removal of many parts of the hull. Other factors that make the cotyledons soft or fragile, such as altered starch composition, will make dehulling difficult. Ease of dehulling is an objective in several grain legume breeding programmes around the world, particularly for lentil, pea and chickpea. When the hull is firmly attached to the cotyledons, dehulling can be a time-consuming process. Dehulling creates by-products such as seed coats, small particles and broken bits of legumes. These can be sold to livestock farmers or feed compounding companies. More recently, a small demand for faba bean seed coats has developed in the pet food industry. [caption id="attachment_24256" align="aligncenter" width="1024"] Figure 2. Cleaned and size sorted faba beans fed into silo.[/caption]
The Arolan Tila processing plant in FinlandThe Arola farm in southern Finland specializes in gluten-free and organic crop production. In addition, the farm operates a dehulling line for food-grade legumes. This automated processing line, with sorting and dehulling stages, can process large quantities and achieve consistently high quality. The technology removes impurities, stones and metal debris before dehulling and splitting of the beans. First, the seeds are cleaned of debris, sieved to include seed sizes of 6 mm – 10 mm, and poured into 750 kg container bags. Seeds that are too small or too large are not suitable for processing, mainly due to equipment limitations, and can be sent for livestock feed. The cleaned beans of the correct size are then put through the processing stages described in table 2. Four machines are used to process the beans into clean splits. The colour sorter removes green, half-green or darkened cotyledons, which could be useful in the event of a poor quality harvest. Nevertheless, a colour sorter adds significantly to the capital cost. It is also possible to have fewer machines - one machine could do the job sufficiently but this increases the chances for impurities in the batch. The removal of dust or flour is an important part of improving the visual quality of the end product. The processing capacity of this unit is roughly 5,000-6,000 kg a day. Cleaning the machinery between cultivars or species normally takes 3-4 hours. There is a wide range of machines on the market with varying dehulling capacities, with some having outputs as high as 6,000-10,000 kg per hour. [caption id="attachment_24264" align="aligncenter" width="1024"] Figure 3. Magnet to remove metal debris.[/caption]
Storing the dehulled productThe dehulled beans are stored in bulk containers (big bags). Processing is done on order, so storage time is minimized. This reduces the exposure to air which starts a process of oxidation that reduces the shelf life of the splits.
LogisticsThe beans are normally placed in flexible intermediate bulk containers – big bags (approved for food purposes) of approximately 750 kg or 1000 litres of material and transported on euro-pallets. Bagging systems can be flexible and are closely linked to customer requirements, as some consignments prefer sealed paper bags, e.g., canteens. [caption id="attachment_24268" align="aligncenter" width="1024"] Figure 4. Elevator and dust build up. Overall the entire process produces a lot of fine dust.[/caption]
Main practice points
- Dehulled beans are used in the food and feed industry.
- Drying before dehulling improves results.
- Sorting and dehulling with specialized machinery saves time and ensures a good quality end-product.
- Processing on order reduces storage time and reduces risks of spoilage from oxidation.
Further informationWood, J. A., and Malcolmson, L. J., 2011. Pulse milling technologies, in: B. K. Tiwari, A. Gowen, and B. McKenna, (Eds.), Pulse Foods: Processing, Quality and Nutraceutical Applications. Elsevier, New York, pp. 193-221.
Effect of soybean cropping on floral diversity
BackgroundAgroecosystems are biodiversity-depleted ecosystems. The expansion of arable land and the intensification of its use has displaced natural habitats and reduced the biodiversity of entire landscapes. Since agriculture dominates land use over most of Europe, increasing on-farm biodiversity is a challenge for policymakers, scientists and land managers. Securing and enhancing the amount of semi-natural habitats, flower strips, intercropping (polyculture), extended crop rotations, the use of perennial crops, organic farming, and the increase in the production of biodiversity-enhancing arable crops are all relevant approaches. The positive impact of perennial forage legume species on agricultural habitats is well documented. Less is known about the effects of grain legumes. The question addressed here is, what can we conclude about the effects of annual grain legumes on farmland floral diversity from the existing scientific evidence. We searched the world-wide academic literature for reports of studies that compared grain legume crops with the crops they replace with respect to the biomass, cover grade, density, evenness, frequency, species richness, hierarchical richness index, seed production, relative abundance and species richness of accompanying flora. It examined the crops grown and crop management as factors that might drive the effects of growing legumes on floral diversity. Agricultural floral diversity is affected by factors such as site history, soil type and local environment variation, and microbial communities. Furthermore, management practices, such as different planting and harvest dates of the crops, tillage, and plant protection regimes, especially their timing, are very relevant. Although legumes are generally seen as crops that support biodiversity, there is little evidence if annual grain legumes integration into European crop sequences will increase floral biodiversity positively.
EvidenceIt was immediately obvious from the search of the literature that there is a scarcity of peer-reviewed evidence about the effects of introducing grain legumes into cropping systems on floral diversity, especially for grain legumes other than soybean. We found 53 sources for soybean. This was followed by pea (17 sources), lupin and faba bean (each two sources). Therefore we here focused only on soybean and chose 25 sources for further analysis, containing analysable information about the effect of soybean on associated flora. The plant parameters which were studied most were weed density, biomass, species richness, and Shannon diversity. Other parameters, such as seed production, weed cover, evenness and hierarchical index, were only seldom found in the literature (Table 1). The available literature covered both emerged weeds and seedbanks in agroecosystems. Data on emerged weeds show the respective current state of weed communities in a crop whereas the weed seedbank provides information about long-term developments. Therefore both values were treated seperately in our analyses. We encountered two issues with the evidence that made further investigation difficult. There were too few publications and the experimental settings were largely inhomogeneous. Still, we extracted the relevant data from the literature to make relative difference comparisons by standardising the results of the various publications (Formula 1). Individual trials with varied location or management within an article, as well as data from different years, were treated as replications to address the lack of repetitions for the quantitative analysis. Annual data consisted primarily of a composite measurement of replicates in parcels at various times during the growing season. Four replications were required as a minimum.
ResultsTaking all experiments and data into account, other crops (mostly maize, sorghum, sunflower and wheat) supported more floral diversity of emerged weeds than soybean. The difference amounted on average 150% for weed biomass, 135% for cover grade, 110% for density and 125% for seed production compared to soybean (Figure 1). The difference was smallest for species richness. Only maize had a lower floral diversity than soybean. The results for the effect of cropping sequences that include soybean on the soil seedbank are less conclusive. Sites where soybean is included in the cropping sequence had a 36% higher weed seed density than sequences with less soy. Evenness, Shannon diversity, and species richness in the seedbank differed by less than 10% between soy-free sequences and sequences with different amounts of soy (Figure 2). Longer cropping sequences tended to support a higher floral diversity as indicated by the Shannon diversity. All polyculture measures, cover crop use, double-cropping, or intercropping resulted in reduced biomass of emerged weeds. In intercropping systems, the partner crop to soybean seems to play a decisive role in its influence on floral diversity parameters. Overall our global data analysis showed that intercropping soybean with a crop partner increased species richness by 38% compared to single soybean (Figure 3) even though weed biomass is reduced. This dynamic was also given for other studied crops compared to their intercrop. Systems with soybean tended to have increased plant diversity where tillage was reduced. Crop protection measures resulted in more uniform plant communities, while diversity remained almost unaffected.
ConclusionsThe evidence about the effect of soybean production on floral diversity is weak. Crop factors such as varying crop emergence times, canopy light interception, variations between autumn and spring-sown crops, and the presence of allelopathic chemicals impact weed diversity in different crop ecosystems. Crop traits and weed management are possible reasons for the low floral diversity in soybean compared to other arable crops. Soybean can successfully suppress accompanying vegetation because of its closed canopy. It reaches full ground cover earlier than corn. Furthermore, weeds are intensively controlled in soybean independent of the weed control system used (herbicide tolerance or conventional). Soybean introduction into crop sequences improved weed seedbank density despite being weak in terms of emerged weed biomass in single crop comparisons. This may be due to the short soybean growing period and the innate difference of both weed parameters. The results presented here offered some insights into the effect of soybean within polyculture systems. Using cover crops in soybean cultivation negatively impacted floral diversity parameters. The high crop plant densities in additive intercropping inhibits weed growth. Compared with other crops, the evidence indicates that soybean crops have less weed biomass compared with other crops in cropping systems. Diversity oriented parameters such as Shannon diversity, evenness, and species richness remained almost unaffected. Surprisingly, weed seedbank density, contrary to the observations for emerged weeds biomass in crop comparisons, was positively influenced by including soybean in the crop sequence. We conclude that the integration of soybean in European crop sequences generally has a neutral effect on floral diversity. [caption id="attachment_23201" align="aligncenter" width="1024"] Soybean flower close-up.[/caption]
DefinitionsCover grade: the proportion of the land or soil surface covered by plants, usually given as fraction 0-1, or percentage. Density: the number of individuals per unit of area or space. Evenness: how equal the distribution of individuals of species is between samples. This is a structural parameter for comparing different communities. Frequency: the number of times a species occurs in a defined area in a given time. Species richness: the number of species per unit area. Shannon diversity index: an index of diversity based on the number of species and number of individuals per species.
Cultivar selection for spring faba bean
'Bundessortenamt' description of cultivarsThe 'Bundessortenamt' provides a descriptive list of faba bean cultivars for use in Germany. The properties of the faba bean varieties included in the list are characterised on a scale of 1 to 9. For traits such as yield, crude protein content, TGW, plant length, etc., grade 1 is a low score for the trait, grade 5 a moderate expression of the trait, and the score 9 a very high expression of the respective trait. Table 1 shows the faba bean varieties described in the BSL including the variety description by means of the grading scale.
Grain yieldAt first glance, the grain yield potential of a variety often plays the most important role. This criterion is particularly relevant where the crop is sold under current common trading conditions. In Germany, quality parameters such as protein content or grain size still rarely influence pricing when marketing to the agricultural trade or to processing companies. However, this could change in the future, especially with regard to the use of faba bean in human nutrition. Table 2 shows the average grain yields of faba bean harvested in Germany in the past 10 years. Of the cultivars listed in the BSA's BSL 2020, the following have yielded particularly well in German trials:
- GL Sunrise
Crude protein contentThe crude protein content is particularly relevant to processing companies that feed the harvested faba beans themselves. When marketing to the human sector, higher crude protein contents can lead to price premiums. In the case of trade between arable farming and processing companies, a fair pricing could be realised on the basis of the crude protein content as a value-added ingredient. From the crude protein analyses of the variety tests, the BSA indicates an average crude protein content of approx. 25% (at 86% dry matter (DM)) across all faba bean varieties. This corresponds to approx. 29% crude protein in the dry matter. According to BSL, the following variety has a comparatively high crude protein content:
- LG Cartouche (BSL 2020, no longer included in BSL 2021 due to insufficient number of test sites)
Crude protein yield per areaTogether with the grain yield potential, the crude protein content results in the crude protein yield per area. Most varieties with high grain yields have rather low crude protein contents, but still perform quite well in terms of crude protein yield per area due to the high mass yield. The crude protein yield per area is also primarily of interest to finishing farms. Especially when it is simply a matter of ensuring the total protein requirement, and less about the last gram of crude protein, i.e., the crude protein concentration, per kg DM of the feed ration. Of the varieties listed in the BSL, the following have a comparatively high crude protein yield per area:
- LG Cartouche (BSL 2020)
- GL Sunrise
Antinutritive ingredientsMany of the available faba bean varieties contain the antinutritional substances tannin, which is found in the faba bean husk, and vicin and convicin, which are found in the grain. In monogastric feeding, these substances have a negative effect on feed intake and performance above certain concentrations. Tannins can lead to a lower feed intake (bitter substances) as well as to a deterioration in protein digestibility. Vicin and convicin have a negative effect on the performance of laying hens. In ruminant feeding, however, these substances do not play a role. Tannins are even considered to be more beneficial, as they can somewhat increase nutrient stability in the rumen. The content of antinutrients is also relevant, especially for livestock farms. It can therefore make sense to switch to varieties that are free of some or even all of the aforementioned ingredients through breeding. In the field of human nutrition, the parameter of antinutritional ingredients is not yet relevant, at least in Germany. Particularly in the case of low-tannin varieties, however, this breeding success seems to be accompanied by a reduced grain yield capacity. Alternatively, tannin-containing varieties could be hulled before feeding. Varieties with low tannin content are the following, according to BSL:
- GL Sunrise
Thousand grain weightThe TGW, and thus the grain size, of common faba bean varieties varies in a range from approx. 350 to 750 g. Varieties with a high TGW cause higher seed and sowing costs, as more mass of seed must be used for the same number of seeds per m². Particularly in the case of additionally poor germination capacity, the calculated required seed quantity per ha can exceed the technically feasible maximum application rate, depending on the seed drill. In addition, particularly large faba beans can cause problems with the sowing and conveying technology. If these are not designed to move such large grains, blockages and grain breakage can occur on seed wheels or augers. For human nutrition, large-grain faba beans are demanded and are also better paid. In addition, large-grain, tannin-containing faba beans have a lower tannin content than small-grain tannin-containing varieties. This is due to the fact that the tannins are mainly found in the skin. Due to the surface/volume ratio, the hull of large-grain varieties has a lower proportion of the total grain than that of small-grain varieties. Of the varieties listed in the BSL, the following have a comparatively high TGW:
- GL Sunrise
Susceptibility to diseaseAs regards susceptibility to relevant faba bean diseases, there are only significant differences between the varieties for faba bean rust. As faba bean rust is relatively heat-dependent, it tends to occur in warmer growing regions. If you are in such a region and have increased problems with this disease, you should rather use varieties that are less susceptible to rust, or be particularly attentive in conventional cultivation in order to be able to react to rust outbreaks at an early stage. Of the varieties listed in the BSL of the BSA, the following have a low to medium susceptibility to rust:
- GL Sunrise
- LG Cartouche (BSL 2020)
Key practice points
- The differences between the few available faba bean varieties are relatively large in some characteristics.
- Before choosing a variety, the grower must be clear about the individual conditions and possibilities regarding cultivation and utilisation or marketing. From this, the demands on a faba bean variety can be derived.
- These requirements must then be compared with the available range of faba beans in order to filter out the most suitable variety.
- As new varieties regularly appear on the seed market, it is helpful to find out about these new varieties every year. Promising varieties are tested in independent variety trials of the respective national institutions in "national variety trials" and the results are published.
Further informationThe results of the German land variety trials for faba bean can be found under the following links: https://www.demoneterbo.agrarpraxisforschung.de/index.php?id=180 https://www.isip.de/isip/servlet/isip-de/infothek/versuchsberichte
Effects of soybean cropping on arthropods
BackgroundMany agroecosystems are biodiversity-depleted ecosystems. The expansion of arable land and the intensification of its use has displaced natural habitats and reduced the biodiversity of entire landscapes. Since agriculture dominates land use over most of Europe, increasing on-farm biodiversity is a challenge for policymakers, scientists and land managers. Securing and enhancing the amount of semi-natural habitats, flower strips, intercropping (polyculture), extended crop rotations, the use of perennial crops, organic farming, and the increase in the production of biodiversity-enhancing arable crops are all relevant approaches. The positive impact of perennial forage legume species on agricultural habitats is well documented. Less is known about the effects of grain legumes. The question addressed here is what we can conclude about the effects of soybean on farmland biodiversity, arthropods in particular, from the existing scientific evidence. We searched the world-wide academic literature for reports of studies that compared grain legume crops with the crops they replace with respect to the number of individuals of invertebrate taxa (activity density), the number of species (species richness), and the distribution of individuals and species (Shannon diversity and evenness). This assessment covered a range of taxa and functional species groups. It examined the crop species grown and crop management as factors that might drive the effects of growing soybean on biodiversity.
EvidenceIt was immediately obvious from the search of the literature that there is a scarcity of peer-reviewed evidence about the effects on arthropods of introducing grain legumes into cropping systems, especially for grain legumes other than soybean. We found 21 reliable studies on soybean. Most sources originated from North and South America. Of these, 16 compared soybean with other crop species, six focused on cropping sequence, and two examined intercropping of soybean with each wheat and sunflower. Five sources compared the effect of crop management factors such as tillage, fertilisation, and weed control. Only four sources included landscape scale effects. Table 1 provides an overview of the range of studies identified. Activity density was the most studied parameter, followed by species richness. Shannon diversity, evenness, and hierarchical richness index were only rarely studied. Overall, and taking all organism groups into account, information on soybean effects on arthropods is fragmented and was studied in combination with a wide range of crop management parameters. Since only about half of the studies indicated an error or variance analysis, a classical metaanalysis could not be conducted. Therefore, our analysis is based on the relative differences between means with the effect’s direction shown by a plus/minus sign, i.e. plus when soybean had a positive effect, minus when soybean had a negative effect (Formula 1). For example, for the biodiversity parameter species richness with a value of 20 for soy and 10 for maize, the relative difference amounts +100%. There were comparisons of soybean with roughly 16 different arable crops, with maize being the most common. We averaged all comparisons between soybean and other mainly non-leguminous arable crops (grouped as “other crops”) to allow us to consider all the data available. We treated observations from different experiments and years as replications for the testing of effects with the minimum number of replications being four. In a second evaluation step, we combined data on groups of organisms to generate estimates for all arthropods. We also aggregated data according to functional groups. Species that are primarily herbivores were distinguished from all predominantly predatory taxa such as spiders and ground beetles which together with parasitoid wasps were grouped as natural enemies.
ResultsThe evidence available allows us to consider the effect of soybean with reasonable confidence. Soybean crops had overall a higher activity density and species richness of arthropods compared to widely grown crops (Figure 1). Herbivore activity, density in particular was higher, followed by predator activity density. The species richness of natural enemies was also higher in soybean compared to other crops. Furthermore soy increased the activity density of mites and ground beetles. From nine individual comparisons with other arable crops, soy had a higher activity density of spiders in six cases. For the assessment of the sequence two kinds of data were available; one in which soybean was part of two sequences, but one sequence was short (two years), and the other was long (four years). The other kind of data were comparisons between sequences with and without soybean. For arthropods as a whole, the differences in diversity and activity density associated with crop sequence length or soybean use or absence was slight. A pre-crop effect could be identified on the activity density of arthropods and ground beetles in particular, which was respectively higher in the crop succeeding soybean. Most diversity parameters of arthropods in soy were lower in soy with cover crop in comparison to soy as sole crop. Intercropping of soybean with a partner crop revealed no clear picture regarding activity density, species richness or Shannon diversity of arthropods. Landscape heterogeneity, increased by the presence of semi-natural habitats, positively affected arthropods in soybean crops. A high percentage of cropped area, including soybean cultivation, in a landscape resulted in losses of activity density and species richness of e.g. wild bees, other pollinators, ants as well as natural enemies and herbivores. Across all management factors, only for weed control we found reliable information: increasing weed control measures reduced arthropod activity density and species diversity.
ConclusionsThe biodiversity in an arable crop is the consequence of the crop species, crop management, and its landscape context. In assessing the findings presented here, it must be remembered that all observations relate to biodiversity-depleted agro-ecosystems. The differences observed generally relate to very few studies and hence a low evidence base, in particular for European soy-based cropping systems. That said, there is still reasonable consensus in the literature that soybean crops can support a higher abundance and species richness of arthropods compared to other crops. This may be due to the protein-rich biomass combined with the more open canopy architecture in the young crop. The increased activity density of herbivores in soybean compared to other widespread crops is striking, even if it is based on few replicates. Presumably, this is related to the aforementioned attractiveness as a food source. However, it is critical to consider whether increasing soybean cultivation in Europe would have to be accompanied by more intensive plant protection measures with potentially negative effects on non-target arthropods. The observed pre-crop effect on arthropods may be related to the high nutrient value of soybean crop residues. It could be expected that a higher length of a crop rotation would increase microvariability in the field over time but such impacts were not thoroughly investigated so far. The evidence available indicates that the introduction of soybean into cropping systems otherwise dominated by cereals increases infield activity density and species richness of arthropods. All in all we think that, especially considering the wider agro-ecological contexts in Europe, the integration of soybean in European crop sequences is likely to have a positive effect on in-field biodiversity, as long as soybean cultivation would stimulate crop diversification. In order to increase the availability of information regarding this topic we recommend to increase systemic research on biodiversity impacts of grain-legume supported cropping systems in Europe. A cataloguing of organism groups (trophic groups and taxa) associated with the respective arable crops as well as cropping systems with and without legumes especially in grain legumes other than soybean from field to landscape scale would be helpful for guiding further developments of grain legume cultivation. [caption id="attachment_23040" align="aligncenter" width="1024"] Soybean grown in a field experiment, Müncheberg, Gemany[/caption]
DefinitionsActivity density (AD): the number of individuals or species moving over a defined area or crossing a defined border in a given time. Species richness (S): the number of species per unit area. Shannon diversity index (H): an index of diversity based on the number of species and individuals per species. Evenness (E): how equal the distribution of individuals of species is between samples. This is a structural parameter for comparing different communities. Hierarchical richness index (HRI): comparative assessment index of the dominance of different organism groups calculated from abundance scores.
Maize and runner bean intercropping
Practical considerationsThe most important practical consideration is the choice of bean cultivar. The key traits are seed size, time of maturity, and the phytohemagglutinin (phasin) content. Phasin is a toxic substance found in raw phaseolus beans. Seed cost is also a consideration.
Cultivar selectionFor some years now, breeding has concentrated on improving the suitability of both mixture partners for mixed cultivation. Where silage for feeding is grown, low-phasin, high-yielding, small-seeded cultivars with a high protein content should be selected. The cultivar WAV 612 with a thousand grain weight (TGW) of only 225 g is an example. The grain size of the beans is an important feature. The large seed means seed costs are high and sowing the beans and maize together using precision seeders is difficult. The seed of the bean and maize should be similar in size if they are to be sown together using a precision seeder. Cold-tolerant bean varieties that have a high proportion of early, well-formed pods up to harvest should be used. It is also important for the maize to have good stability with good resistance to stem rot. The dry matter content of runner bean is low at harvest (about 20%) and decreases with time as harvest is delayed into late autumn. Late harvesting should be avoided. Early maturing maize cultivars should be chosen. Otherwise, the dry matter content of the mixture could be too low due to the bean content, making successful ensiling more difficult. The earlier ripening maize cultivars can compensate for the low dry matter in the beans because they have a high dry matter content at harvest.
Cultivation methodsSites with medium to good water supply and low to moderate weed pressure are suitable. The bean seed should be inoculated with the appropriate rhizobia where the runner bean is grown on a field for the first time. Simultaneous sowing of maize and beans has proven to be more cost-efficient and practical. Conditions are often already too dry if the beans are sown later than the maize. In addition, later sowing of the beans disturbs the soil shield effect of pre-emergence herbicides greatly reducing their effectiveness. The bean is more frost sensitive than the maize. Late frosts can damage the bean while the maize is unaffected. Therefore, depending on the region, the joint sowing should take place somewhat later (around the beginning of May) than the sowing of the pure maize crop. The result is the seed of both species is concentrated in the same rows which leads to shading and thus suppression of weeds within these rows. Widely used maize row spacings are suitable. However, if the row spacing is lower than 50 cm, there is a risk that the beans will interfere with the neighboring row, which can lead to problems at harvest. The sowing depth is a compromise between the requirements of both crops but should tend towards that of maize as the main biomass producer. The target plant density is in the range of 6-9 plants/m2 for maize (only very slightly reduced compared to pure stands) and 3-6 plants/m² for beans. The proportion of the crop biomass provided by the bean increases with increased bean sowing rate but the total dry matter yields tend to be reduced. It is recommended not to set the bean proportion in the mixture too high due to the phasin content and the weight and long reach of the beans, which can become a problem during harvesting due to breakage of the maize stems. The high performance of the maize must be protected. It should be complemented by the bean, but not hindered. The basic nutrients phosphorus and potassium should be in the optimal range. Farm manure can be used and, depending on the supply situation, mineral fertiliser can be added. Only pre-emergence herbicides can be used. The post-emergence herbicides otherwise approved and commonly used on maize in Germany may not or cannot be used on runner bean. The only herbicides that can be used in Germany are pendimethalin (e.g., “Stomp Aqua") and pendimethalin plus dimethenamid P (e.g., "Spectrum Plus"). The use of mechanical hoeing is also an option. A hoeing operation can be carried out shortly before the closing of the crop canopy when the effect of the soil herbicides has worn off. The use of a stale seedbed is common in organic farming. This may be combined with careful tined weeding at the 3-leaf stage of the maize onwards. Inter-row hoeing with crop protection plates can also be used from the 3-leaf stage of the maize. Later on, the row can also be carefully ridged. However, maize and runner bean plants should not be covered with soil. The mixture is harvested with a forage harvester fitted with a maize header, which may be equipped with a side knife that cuts through the mass of climbing beans.
Opportunities and impactsThe cultivation of maize-runner bean mixtures is eligible as a separate crop under the crop diversification agri-environmental measure in some German federal states if the runner bean accounts for at least 25% of the crop plants.
Yield and crude protein contentWith about 14% crude protein in the dry matter (DM), the protein concentration of the bean crop is about twice that in maize (5-7% in maize). The beans account for 10-15% of the total try matter. The crude protein content of the forage mixture increases by about one percentage point to around 6-8% crude protein in the DM if the seeding ratio described above is used. This increased protein content reduces the need for supplementation with high-protein feeds. With yields of the current bean and maize cultivars and the current growing techniques, the total dry matter yields of the intercrops are about 10% lower than those of maize pure stands. The crude protein yield per ha is about the same as that of maize pure stands.
BiodiversitySilage maize is grown on 2.3 million hectares in Germany. This is the second largest crop area after wheat. Especially in regions with a high proportion of maize, the introduction of another crop can promote biodiversity and the public acceptance of cultivation systems. Initial studies indicate that the flowering bean in the mixture seems to have a particularly positive effect on bumblebees.
Nitrogen economyThe beans fix nitrogen where soil mineral nitrogen supply is low. Biological nitrogen fixation is greatly reduced and may be prevented completely where soil supplies are high enough for good crop growth. Research has shown that the maize-bean mixtures are better able to maintain total dry matter yields compared with maize pure stands where nitrogen fertilisation is restricted. In addition, a reduction in N fertilisation in pure and maize-bean mixed stands lowers post-harvest mineral nitrogen level in the soil. These observations suggest that the mixed stand is able to utilise soil mineral nitrogen but that the beans compensate where there is nitrogen deficiency. This can be particularly interesting in regions or situations where the application of nitrogen-containing fertilisers is constrained due to legal restrictions.
Ground coverThe shading effect of runner beans in maize stands suppresses weeds and can reduce the need for mechanical control measures in organic farming. Due to the spreading early growth of runner beans and the higher total number of plants per m², the soil is shaded more quickly and unproductive evaporation from the soil is reduced. This tends to help the crop survive dry periods. Maize cropping is associated with a high risk of soil erosion due to the late sowing in spring. This problem can be partially alleviated by the faster soil cover in mixed cultivation with beans. [caption id="attachment_20199" align="aligncenter" width="661"] Maize and bean mixed in a row[/caption]
Feeding maize-bean silageA mixed-silage of maize and beans can be used for dairy cattle and as a roughage in pig fattening. Because of its high phasin content, maize-bean silage was formerly rarely used in feeding. However, the proportion of beans in the mixture is usually only 10-15% of the dry matter (the decisive factors are seed density and timing, as well as the choice of variety). Ensiling reduces the phasin content. In addition, breeding is increasingly focused on low-phasin cultivars. However, the proportion of beans can also be kept low by ensiling with pure maize, so that the phasing content of the maize-bean silage only very rarely becomes a constraint. The ensiling of the crop is usually straight-forward if a dry matter content of about 30- 35% is achieved. In feeding trials, maize-bean silage (9% bean dry matter in maize-bean silage) led to the same milk yields or, in pig feeding, to the same fattening performance and carcass quality with comparable animal health. The silage is both well absorbed and digested by dairy cattle and pigs where introduced gradually. Phasin is partially degraded in the rumen of cattle. Only the urea content in the milk can increase slightly.
Key practice points
- Mixed cultivation of maize and runner bean increases the crude protein content of the silage.
- On-farm biodiversity is supported.
- Simultaneous sowing of both mixture partners in customary maize row spacings has proven successful.
- When choosing the pole bean variety, make sure the grain size and shape are similar to those of maize (with simultaneous precision seeding) as well as having a low phasing content (e.g., the WAV 612 variety).
- The target stand density is 6-9 maize and 3-6 bean plants per m².
- Only fields with low to medium weed infestation should be selected for cultivation due to very limited possibilities in chemical weed control.
- Mechanical weed control can be carried out with a harrow and hoe in a similar way to pure-stand maize cultivation.
- Compared to silage maize cultivation, approx. 10% lower total dry matter yields and approx. 10% higher crude protein contents can be expected.
- Due to the N-fixation of runner beans, N- fertilisation can be reduced compared to pure-stand silage maize cultivation.
- Ensiling is easy if the dry matter content of the crop is between 30 and 35%.
- The mixed silage can be used in both cattle and pig feeding.
VideoThünen Institute, https://vimeo.com/thuenen
Web linksBayrische Landesanstalt für Landwirtschaft, Mischanbau von Mais zur Substratproduktion und Futtererzeugung, www.lfl.bayern.de/ipz/mais/148685/index.php Thünen Institut, Mais und Bohnen im Gemenge, www.thuenen.de/index.php?id=2280&L=0 Landwirtschaftskammer Niedersachsen, Mais-Mischkulturen erfolgreich anbauen, www.lwk-niedersachsen.de/lwk/news/35477_Mais-Mischkulturen_erfolgreich_anbauen?nav=183
Nutritional value of grain legumes
Protein solubility is not a reliable indicator of rumen degradabilityProteins in less commonly used grain legumes, such as in pea and lupin, are highly soluble and so the in sacco (nylon bag) technique over-estimates protein degradability because protein washes out of bags irrespective of whether it is degraded. Soluble protein from lupin seeds can escape rumen degradation. Recent work with rapeseed proteins showed that soluble proteins can be adsorbed to microbial cells or taken up directly into microbial cells. Both pathways result in more under-graded protein passing from the rumen than would be predicted from protein solubility.
Solubility methods produce widely divergent values for grain legumesIt has long been known that factors such as extraction time, pH, ionic strength, and temperature affect protein solubilisation and this seems to be particularly evident for grain legumes. De Jonge et al. (2009) showed that there were large effects of pH on N solubility (Figure 1), with much lower solubility at lower pH levels (5.0–5.6) that are quite common in high producing ruminants. Given these effects, it is not surprising that there are no consistent relationships between measurements of N solubility and estimates of N degradation based on in sacco or in vitro measurements. Results from Kandylis and Nikokyris (1997; Figure 2), de Jonge et al. (2009; Figure 3) and our own results of analysis of N solubility using pH 6.8 buffer, water, or a 16-hour in vitro incubation with buffered rumen fluid (Figure 4) all confirm that N solubility methods are not an appropriate method for evaluating the nutritional value of pea, faba bean or lupin – nor for comparison with soybean meal (for which laboratory methods are more secure).
Key practice points
- The nylon bag technique under-estimates undegradable dietary protein (UDP) supply from grain legumes. Estimates of protein (N) degradability should not be based on in sacco (nylon bag) techniques for such highly soluble feeds.
- Significant proportions of soluble protein can pass from the rumen undegraded. This means that promising grain legumes, such as pea, bean and lupin, may have been under-valued relative to other protein sources, including soybean meal.
- Solvent characteristics, particularly pH, have a very large effect on protein (N) solubility estimates for grain legumes. Low pH (acid condition) leads to lower values for degradable protein.
- This latter effect will also occur in the rumen so that protein degradability values for grain legumes will be much less when included in diets leading to lower rumen pH (5.6 and below). This is potentially a very useful phenomenon because requirements for undegraded dietary protein are often highest in high performing ruminants that are offered higher levels of high concentrate diets, resulting in lower rumen pH. Thus, the under-estimation of protein value of grain legumes may be most pronounced when feeding the most productive ruminants.
Faba bean, grain pea, sweet lupin and soybean for feeding cattle
Agro-economic prospects for expanding soybean production beyond its current northerly limit in Europe
Faba bean, grain pea, sweet lupin and soybean for pig feeding
Feeding extruded soybean to pigs
Case study dataTwo experiments were conducted. The Danube White breed was used in the first, and a Danube White x Pietren cross was used in the second. The first experiment was performed using three treatments (I (control), II and III). The Treatment II group were fed a compound feed in which 50% of the soybean meal was replaced on a protein basis by extruded full-fat soybean from the Bulgarian cultivar Srebrina. In Group III, 75% of the soybean meal was replaced by protein extruded full-fat soybean (Table 1). In the second experiment with 2 groups (I (control) and II (experimental), extruded full-fat soybean of the Bulgarian cultivar Richy was used. In the experimental group, 30% of the soybean meal (by was replaced by extruded full-fat soybean on a protein equivalent basis (Table 2). Both experiments were performed over two rearing periods: the first from the weanling pigs 20 kg to 60 kg live weight, and the second from 60 kg to the end of fattening. Blood samples were taken at the end of Period 1 at 60 kg live weight to determine the values of MDA in blood plasma. This indicator was studied as a marker of oxidative stress.
The formulation of the feeds used in experiment 1 to examine the effect of replacing soybean meal with extruded full-fat soybean from cv. Srebrina for the control treatment (I) and the two experimental treatments (II and III).
Data analysesFeed intake, growth and feed conversion efficiency were measured. From the results of the first experiment we conclude that extruded fullfat soybean cv. Srebrina could be successfully included in the protein component of feed for growing pigs with a live weight of 30 to 60 kg, thereby replacing 50% of soybean meal on the basis of protein equivalent. In experiment 2, there was practically no difference between treatments for feed and nutrient intake and there were no significant differences in the average daily gain and feed conversion efficiency. We conclude that extruded full-fat soybean can contribute up to 30% of the protein in the ration for fattening pigs without adverse effects. Malondialdehyde (MDA) is an end product of lipid peroxidation and is widely used as an indicator for the determination of oxidative stress. Lower MDA blood plasma values indicate lower oxidative stress. The data from the first experiment showed that animals from the experimental Group III with a higher percentage of extruded soybeans included in the feed composition were found to have the lowest level of detected MDA in the blood plasma (0.0277 nmol/μL) followed by Group II (0.0310 nmol/μL) and the control (0.0337 nmol/μL). All differences between group means were significant. There were also differences in the amount of MDA in blood plasma of animals from two experimental groups in the second experiment. The level of MDA in experimental Group II was 0.0438 nmol/μL while that in the control group I was 0.0594 nmol/μL.
Maize intercropped with climbing beans
Valuing faba bean and pea for feed
Numerous scientific studies show that livestock can be successfully fed with protein-rich cool-season grain legumes such as faba bean, pea and others. On the basis of the ‘Löhr substitution method’, it is possible to compare different feedstuffs with standard feeds based on soybean considering energy and protein content. This indicates the point at which an alternative feedstuff costs as much as the feedstuffs currently used, with approximately the same feed value.
This article helps in calculating the approximate equilibrium price of grain legumes in comparison with other protein and energy sources. With the help of this equilibrium price, a decision can be made as to which feedstuffs are economically preferable for the same feed value (energy and protein).
Some constituents of the feeds to be compared must be known to calculate the substitution value of faba bean and grain pea using the Löhr substitution method. The parameters shown in Table 1 are used.Ideally, data for these parameters are available from analyses of the feed ingredients themselves. Published standard values for many ingredients are available but these are often not sufficiently accurate in specific situations to give an accurate assessment of value. The additional costs of using European-grown grain legumes associated with transport and initial processing must be considered so that the faba bean or pea is compared properly with soybean meal.
Calculation aidsThere are some freely available Excel-based applications that can be downloaded from the internet. These can be used to calculate the value of a new feed ingredient based on how it substitutes for an existing standard feed ingredient. The Excel application "Comparative value of feed - substitution values of feed" from the Landesanstalt für Landwirtschaft, Ernährung und Ländlichen Raum Schwäbisch Gmünd (LEL) covers a range of animal species and types. It is available for download here: https://lel.landwirtschaft-bw.de/pb/,Lde/Startseite/Unsere+themes/animal-keeping A wide variety of feed ingredients can be selected and compared. For a selected feed component, e.g., faba bean, the programme indicates the substitution price in comparison to two comparable components, usually a protein and an energy supplier such as soybean meal and wheat. It also calculates how much of the previously used feed can be replaced by the alternative feed.
Calculation examplesTable 2 provides data for the ingredients of the feeds compared later. Table 3 provides data on the value of faba bean for fattening cattle as determined by the cost of soybean meal (45% CP) and the cost of wheat. Table 4 provides the equivalent data for pig fattening. The substitution value is the value of the alternative as determined by the value of the standard materials it replaces. If the calculated substitution value of the alternative feed is higher than its current market price, including transport and processing (e.g., to meal), its use reduces costs compared to the use of the established standard feed component. An example based on the scenario from Table 3 illustrates this:
- Standard feed component prices: wheat (€150/t) and soybean meal (€400/t)
- The substitution value of faba bean is €268/t (Table 3).
- Alternative feed component: Faba bean €240/t (purchase price €220/t + €20/t transport and processing)
Limitations of the methodThe presented method takes into account the two feeding parameters energy and protein content of feedstuffs. Many other parameters such as crude fibre content, digestibility, rumen resistance, etc., also play an important role in optimal ration design. In addition, many other feedstuffs which influence and complement each other are usually included. Therefore, it makes sense in specific cases to prepare a detailed ration calculation with the alternative feedstuff after calculating the substitution value in order to evaluate it fully and to be able to make a well-informed decision. [caption id="attachment_16501" align="aligncenter" width="1024"] Faba bean[/caption]
Key practice points
- A substitution value must be calculated using comparison with the feedstuffs previously used to assess the economic effect of using faba bean and grain pea as alternative feedstuffs.
- The energy and protein contents of the feedstuffs, the purchase prices, and any transport and processing costs must be known.
- The actual calculation can be carried out using freely available software tools.
- If the purchase price of alternative feedstuffs including transport and preparation is lower than the calculated substitution value, their use becomes economically viable. This use should be further checked with a detailed ration calculation.
Combinative breeding for large seeds in soybean
Edamame: Soybeans fresh from the garden
Soybean growth stages and requirements
Cold-pressed soybean for poultry
Case study dataWe examined the effect of the feed used by three different egg producers. These egg producers are located in north-west and north-central Bulgaria. All three are specialised egg and poultry producers with their own feed mills. Two used imported soybean meal as the sole high-protein supplement source in the feed. The third producer (Producer 3) used own-grown (Bulgarian cv. Srebrina) cold-pressed soybean cake as the source of 50% of the soy-based protein in the feed, the other 50% provided by imported soybean meal. Feed samples taken from each of the three producers were analysed in a certified laboratory for energy (MJ/kg) and the contents (%) of protein, fat, starch, and total sugars (Figure 1).
Data analysesEgg samples were taken from the producers for analysis of the content of amino acids and fatty acids. The analyses were performed separately on egg yolk and egg white by using gas chromatography/ mass spectrometry (GC/MS). The content of free AAs of egg yolk and egg white is presented in Figure 2 and Figure 3. The content of free AAs in egg yolk indicated higher levels of each of the detected AAs in the egg yolk from producer 3 with the exception of lysine. Similar results were obtained for the content of free AAs in egg white. The contents of all detected AAs were higher in the egg samples from producer 3. The content of the free FAs was also evaluated in the egg samples (yolk and white) collected from the producers 1, 2 and 3. Figure 4 shows the content of two saturated and five unsaturated FAs in egg white and egg yolk. The highest content of unsaturated FAs was detected in egg white and egg yolk samples from producer 3. The same trend was observed for saturated palmitic acid, and the only exception was the content of stearic acid in egg white where the value of stearic acid was higher in the egg white samples from producer 2.
Key practice pointsCold pressing of soybean grain is an easy process which does not require very expensive equipment. The inclusion of soybean cake in the animal feed on the other hand could benefit animal health and the quality of the final product. In our case study, we found that feed for laying hens in which 50% of imported soybean meal is replaced by soybean cake produced from locally grown soybean could increase the content of free AAs and FAs in thefinal product and benefit the quality of eggs. The essential AAs (histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine) and FAs (linoleic acid (an omega-6 fatty acid) and alpha-linolenic acid (an omega-3 fatty acid)) cannot be synthesised by humans and animals and must be taken in through the diet for normal development and healthier nutrition. [caption id="attachment_20772" align="alignnone" width="681"] Soy cv Srebrina growing in Bulgaria.[/caption]
Further informationAs part of the European project “Legumes translated” ID 817634, www.legumestranslated.eu, aiming to promote the cultivation and use of leguminous crops in Europe – the Bulgarian Legumes Network /BGLN/ performed this case study.
Soya, soya isoflavones and health effects
Field trials on N-fixing cover crops & green manures in Scotland
NotesPlease cite as: Walker, R., Baddeley, J., Topp, K., Cole, L., Watson, C., 2022. Cover crops & green manures. Legume Hub. www.legumehub.eu
Water use and irrigation in soybean
Water requirements at growth stagesSoybean uses water efficiently. Depending on weather and soil, it uses 400–700 mm water as rainfall, irrigation or from soil to form a yield of 3 tonnes/ha. Soybean uses 1,300 to 2,300 tonnes of water per tonne of soybean produced. This is comparable with sunflower and lower than rapeseed. The rate of water use changes as the crop develops. Soybean seeds absorb about 50% of their weight in water when germinating, so moisture in the upper soil layers is essential. Rolling a freshly sown field under dry conditions helps to improve seed-soil contact and the supply of soil water to the seed. The crop needs about 1.2–2.5 mm of water per day during emergence and seedling development. The water moves from the soil to the atmosphere through evaporation from the soil surface and transpiration from the crop canopy. The rate of evapotranspiration depends on the crop canopy’s response to solar radiation, air temperature, relative humidity, and wind. Water usage increases as the canopy develops to about 2.5–5.0 mm per day. The vegetative stages are less sensitive to water shortages than later reproductive growth stages because the crop loses the capacity to compensate for short periods of stress as the crop progresses (Figure 1). Most water is used by soybeans in the stage of flowering to pod fill when there is a full canopy and a fully developed root system. The crop uses about 5.0–7.5 mm per day at this stage. Water deficit during reproductive stages can result in flower abortion, reduced pod number, reduced seeds per pod and decreased seed size. It has a significant effect on yield. Water consumption declines during the final stages to ripening. [caption id="attachment_21472" align="aligncenter" width="1024"] Figure 1. Soybean daily crop water use or evapotranspiration (ET) from a well-watered field. The blue line depicts the expected ET based on historical data, whereas the red line depicts the daily ET of a specific growing season in Nebraska, USA. This site is characterised by a continental climate. Modified, original source: Kranz, W.L, Specht, J.E., 2012.[/caption]
Water scarcity and stressSevere water stress during the reproductive stages can cause yield decreases of up to 60–70%. Soybean plants react to water deficit by turning the underside of leaves to the sun. The light colour reflects sunlight and decreases transpiration. Prolonged drought stress leads toleaf folding. These responses conserve moisture and protect the crop from heating but also reduce photosynthesis. The plant’s strategy is to conserve moisture during a dry period, protecting the plant until the drought passes when normal growth can resume. [caption id="attachment_20855" align="aligncenter" width="1024"] Water deficit during flowering phase can cause abortion of flowers.[/caption]
Soil water supply for soybeanSoybean roots can reach 1.5–1.8 m into the soil and use moisture efficiently in well-drained soils without compaction. Soil properties have a great influence on the availability of soil water for plants. The main soil properties that are important for irrigation management are field capacity (FC) and wilting point (WP). Field capacity is the amount of water held in the soil after excess water has drained away and the rate of downward movement has decreased. Wilting point (WP) is defined as the minimum soil water content required to prevent the plant from wilting. The permanent wilting point (PWP) is the level of soil water below which permanent damage is done and the plant cannot recover its turgor if the supply of water is restored. The texture of the soil strongly affects its water- holding and water-conducting capacity. The need for irrigation may be greater on light sandy soils than on soils with a finer structure with a higher clay content (see Table 1). Loamy sands have less plant-available water comparing with clay soils. But soils of heavier texture also hold on to water and have a higher pool of unavailable water. Soil compaction within 1 m of the surface significantly limits deep penetration of soybean roots. Compaction causes a restriction of the main root growth. The root system develops close to the surface. In such conditions, soybean plants are more susceptible to temporary drought stress and relatively short dry periods.
Scheduling irrigation for closing the gap between water demand and supplyPlanning irrigation, including the amount of water and timing, takes account of the soil type, the layer to be moistened, and the actual soil moisture content before irrigation.
Assessing soil moistureAssessing soil properties is key to assessing the need for irrigation. Various methods from manual assessment up to automated soil moisture sensors can provide necessary information. Tactile assessment of soil texture is the easiest way. If the soil forms a hand-rolled ball, the soil moisture is adequate. It is recommended to take samples across the field at different depths. The irrigation should begin before any part of the field becomes too dry. Tensiometers enable the more precise assessment of the need for irrigation. Tensiometer is a sealed, water-filled tube with a vacuum gauge on the upper end and a porous ceramic tip on the lower end. When soil is drying, water moves from the tensiometer along a potential energy gradient to the soil through the saturated porous cup, thereby creating suction sensed by the gauge. It is recommended to install the tensiometer at 20–30 cm deep where the majority of the roots are located. The vacuum gauge reading of 50–60 centibars on silt loam and clay soils and 40-50 centibars on sandier soils is a signal to begin irrigation.
SchedulingThe difference between the water content of the soil at the PWP and FC is the quantity of water available to the crop. This fluctuates as the crop grows due to uptake, rainfall etc. It increases due to precipitation and irrigation and decreases due to evapotranspiration. Depletion of 30–60% of available water is considered as “management allowable” depletion. The best conditions for soybean growth and high yields are where available water content in 0.5–0.7 m soil depth remains above 65% of maximum available water during vegetative phases, above 70% at flowering, and 70–75% during pod filling stages. The practical experience shows that irrigation becomes a viable option when available water capacity is between 45 and 65% of the full capacity. The response to irrigation declines as the pods develop. The response after the seeds have fully formed (when they touch each other in the pod) is small and irrigation at this stage can interfere with ripening and crop drying for harvest. [caption id="attachment_21480" align="aligncenter" width="817"] It is recommended to stop irrigation when 50% and more have well developed seeds (seeds that touch each other in a bean).[/caption]
Estimating the right irrigation rateThe overall aim of irrigation is to maintain a water supply at a depth of 0.5–0.7 m. Water evaporates from the surface after each irrigation. Less frequent irrigation with larger amounts reduces the loss of non-productive water. In practice, 30 to 50 mm per application is applied.
Salt concentration of irrigation waterKnowledge about chemical properties of irrigation water is essential in irrigated crop production as they can be a constraint. The total concentration of salts is a practical and common measure to assess the applicability of a water source for an irrigation use. Water sources with a high salt concentration can potentially have negative effects on soil and plant health and should be avoided, see Table 2.
Challenges and limitationsFor an economic and environmentally-friendly irrigation, soil and climate site conditions should be taken into account:
- Soybean is especially sensitive to saturated and poorly drained soils. Poor soil drainage leading to waterlogging increases the risk of root rotting, the spread of diseases, and inhibition of nitrogen fixation. This all leads to ignificant yield reductions.
- Excessive irrigation should be avoided especially where there is a risk of salination under arid conditions.
- Soybean flowers are sensitive to impact damage. The impact of the water in large drops can result in losses of flowers. This can be avoided by adjusting water nozzle and pressure.
- Excessive irrigation can cause surface runoff on soils with poor drainage or on shallow soils.
Application of irrigation in soybean in EuropeSoybean is not very frequently irrigated in Europe as the majority of the soybean area is located in warm-temperate climate zones of central and eastern Europe with more than 500 mm of mean annual precipitation. These growing regions are outside of the typical dry zones in the Mediterranean countries. Irrigation is occasionally used in soybean cultivation to bridge dry periods where the annual rainfall is around 500–600 mm, especially by seed multipliers. Rainfall is usually sufficient to achieve a competitive yield of 2–3 tonnes per hectare. Irrigation systems become essential where the average annual precipitation is regularly below 400 mm. Under these conditions, summer droughts are common and have often severe impacts on spring-sown crops like soybean or maize. For example, the average annual precipitation is about 370 mm in the southern steppe zone of Ukraine. Drought periods of more than 30 days occur in combination with high air temperatures and low air humidity. In this zone, about five – seven irrigations of 300–500 m3/ha (30–50 mm/ha) each are needed during the growing period to obtain 4–5 t/ha of soybean yield. [caption id="attachment_21476" align="aligncenter" width="800"] Circular and tubular sprinklers are much gentler, which is immediately noticeable in the increased yield of soybeans. In addition, watering can be optimally dosed.[/caption]
Key practice points
- Irrigation during vegetative stages can be useful where the crop was sown into dry soil, following late sowing, or if soybean is grown as a second crop.
- High responses to soybean irrigation are noted in the reproductive stages, particularly during flowering and pod filling. If irrigation starts in the flowering stage, it is needed to be continued during the pod filling. Otherwise, a lot of small grains are formed.
- Optimum irrigation water temperature ranges around 20–25°C. Cool water (10°C) or very warm water (30°C) can shock plants and result in reduced performance.
Further informationDecalb Asgrow Deltapine, 2015. Soybean water use and irrigation timing. https://www.dekalbasgrowdeltapine.com/en-us/agronomy/soybean-water-use-and-irrigation-timing.html FAO, 2021. Land & Water – Soybean. https://www.fao.org/land-water/databases-and-software/crop-information/soybean/en/ Kranz, W.L., Specht, J.E., 2012. Irrigating Soybean. Nebguide. G1367. University of Nebraska – Lincoln Extension, Institute of Agricultural and Natural resources. https://extensionpublications.unl.edu/assets/pdf/g1367.pdf Matcham, E., Conley, S. P., 2020. Early season soybean irrigation. Cool Bean. https://coolbean.info/2020/05/13/early-season-soybean-irrigation/ (accessed 13.06.2021) Matcham, E., Conley, S. P., 2020. Soybean irrigation during reproductive growth. Cool Bean. https://coolbean.info/2020/06/16/soybean-irrigation-reproductive-growth/ North Otago Irrigation Company. Calculating the appropriate depth of irrigation. https://www.noic.co.nz/img/Calculating%20the%20appropriate%20depth%20of%20irrigation.pdf Specht, J.I., 2017. High-Yielding Irrigated Soybean Production North Central USA. Presentation at Irrigated Soybean and Corn Production Conference Shipshewana, IN. https://www.canr.msu.edu/uploads/235/67987/resources/2017_Soybean_Meeting/Specht-Soybean_Benchmarking_Project.pdf
Effectiveness of nitrogen fixation in rhizobia
Irrigation of lupin
Lupinus albus cultivationLupin is a promising crop for Greece. It can play a role in livestock feeding in particular. Lupin seeds have a high protein content (up to 44%) and they are also a rich source of calcium, iron, magnesium and phosphorus. Due to its nutritional profile, lupin represents a significant alternative to soybean. White lupin originates from the Mediterranean countries. It has the longest history of cultivation for human consumption of any lupin species, dating back to pre-Roman and Greek times. In the past, a cultivar of white lupin that was bitter was mainly cultivated in Greece. The bitterness is due to alkaloids which are toxic to humans and animals. Lupin seeds were immersed in the sea or were roasted to reduce the alkaloids. Sweet and semi-sweet cultivars with low levels of alkaloids (<0.05%) are now used. The most widely grown cultivar in Greece is the locally adopted cv. Multitalia which is semi-sweet.
Climate and soilSpring-sown white lupin is well-adapted to the cool season. Lupin thrives in a temperature range from 14 to 25°C over a 110–125 day growing period. In warm climates such as in Greece, autumn sowing after the first rains is recommended. Sowing can continue until the end of November. Autumn sowing extends the growing season by about 60 days and brings the harvest forward so that the crop escapes severe mid-summer droughts and heat stress. This approach increases and stabilises yield. Autumn sowing of lupin also allows Greek farmers to grow two crops per year where there is irrigation. [caption id="attachment_20386" align="aligncenter" width="1024"] Young white lupin.[/caption] White lupin requires slightly acid soils (pH 6–6.5), with an active calcium content of less than 3%. It has low demands in nutritional elements. Its deep root system forms large nodules where soil microorganisms (rhizobium bacteria) work symbiotically with the plant to fix atmospheric nitrogen and so enable plants to grow. Part of this nitrogen remains in the soil with legume residues for the next crop contributing further to the sustainability of crop rotations by reducing the need of synthetic nitrogen fertilizer.
WaterUnder Mediterranean conditions, lupin grows in areas with rainfall of 380–450 mm. White lupin is quite drought tolerant, however the prolonged dry periods and high temperatures may cause significant yield reduction. Water supply from the soil at flowering and pod filling is critical for the plant development. Flood or overhead irrigation which results in water logging and soil flooding leads to problems with diseases. The optimum strategy for managing water is to gradually recharge the soil water reserve before severe drought strikes. For the best results, the cultivation strategy should tend towards recharging the soil moisture before depletion. This is where precision irrigation plays a role.
Testing precision irrigationWe conducted an experiment from November 2019 to May 2020 near Larissa in Greece, looking at five different irrigation plans to determine the optimal irrigation protocol for lupin cultivation. Soil analysis before sowing provided information on soil texture and the supply of nutrients. These facts are needed because they can influence the irrigation scheduling and the final yield. For example, sandy soils need to be irrigated earlier than clay soils while soils richer in nutrients such as phosphorus and potassium can amplify a better yield. The selected fields had similar climate conditions, were of similar soil composition and nutrient concentration. We used the exact same fertilisation and cultivation techniques. The fields were sowed in mid-October, using the cultivar Multitalia. The crop stand developed well. There were long periods of drought during the winter and the total amount of rain was not enough to cover crop needs. Sensors in each field collected data on air temperature, wind, rainfall, external humidity, soil moisture, etc. The Drill and Drop type and Enviroscan type ground sensors measured soil moisture in different depths e.g., 10 cm, 20 cm, etc. Data are easily accessible via a web application where farmers see the parameters of interest and act accordingly. These sensors cover a large area, thus providing data for several fields minimising the cost of use. [caption id="attachment_20396" align="aligncenter" width="768"] Lupinus albus grains.[/caption]
Crop responsesWe applied irrigation at different times according to soil humidity, making sure that the total amount of water was approximately the same (Table 1). Irrigation increased yield significantly, from 11.5% to 30.76%, compared to the non-irrigated field. Field 1 was the control field and no irrigation was applied. Rain did not cover the crop needs and total yield was quite low at 2.6 t/ha. The treatments differ in the scheduling of the irrigation. Field 2 was irrigated to keep soil moisture levels high while fields 3 and 4 were irrigated to keep soil water levels at about 20% at 200 mm. This moderate water supply prevented extreme drought stress, maintained crop growth and avoided diseases associated with excessive irrigation. Field 5 was irrigated at the stage where plants were stressed due to a lack of adequate soil humidity. Despite receiving the biggest total amount of water, plants did not recover from the drought stress and the yield was lower than expected.
Key practice points
- Lupin thrives in a temperature range from 14 to 25°C for a period of 110–125 days from spring sowing and about 180 days from autumn sowing.
- In Greece, October sowing is recommended in order to avoid the high summer temperatures.
- Soil analysis helps determine the nutrient availability.
- Irrigation strategy should tend towards recharging the soil water before depletion impacts on the crop.
- Data from sensors covering a large area can be easily accessed via the web.
- Understanding what happens in the plants` root system enables us to make better decisions.
- In case of low winter rainfall, lupin needs irrigation to produce a high and economically viable yield.
- Excessive water accumulation during flowering stage can stress the plants. Irrigation where soil water contents are high is not advised.
- Irrigation should be used in advance to prevent extreme drought stress. Crops that have been subject to extreme drought stress do not recover fully when irrigated.
- Improved water use efficiency saves resources.
Further informationGresta, F., Wink, M., Prins, U., Abberton, M., Capraro, J., Scarafoni, A., Hill, G., 2017. Lupins in European Cropping Systems, in: Murphy-Bokern, D., Stoddard, F.L., Watson, C.A. (Eds), Legumes in Cropping Systems. CAB International, pp. 88-108. Cowling W.A., Buirchell B.J, Tapia M.E., (1998). Lupin, Lupinus L., International Plant Genetic Resources Institute IPGRI. Dalianis Konstantinos. 1993. Legumes for Grains and Forage. Stamoulis Publications, AthensPapakosta - Tasopoulou Despina. 2012. Special Agriculture, Grains and Legumes. Modern Education, Athens. Biala K, Terres J, Pointereau P, Paracchini M. Low Input Farming Systems: an Opportunity to Develop Sustainable Agriculture - Proceedings of the JRC Summer University - Ranco, 2-5 July 2007. EUR 23060 EN. Luxembourg (Luxembourg): OPOCE; 2008. JRC42320. The main sources for soil monitoring are the ground sensors in the field (figure below) for monitoring the plant condition every hour. Data are accessible by a terminal device in a form of table (Table 2). [caption id="attachment_20413" align="aligncenter" width="435"] Soil sensors Drill and Drop (a,b) Enviroscan (c,d).[/caption]
Disease control in faba bean
OutcomeA better understanding of these diseases in faba bean enables growers to obtain higher yields through the targeted use of fungicides. Yields are more secure and unnecessary prophylactic fungicide measures can be avoided. This protects the environment and helps preserve the effectiveness of the few available active substances.
Occurrence and distributionFaba bean rust is more prevalent in warmer areas of central Europe or in warm summers. Infections usually occur at the middle to end of the flowering period. The disease survives on crop residues, winter emerged plants, other host plants and, to some extent, on seed. The spores are spread by wind. Chocolate spot occurs mainly in regions or years with high rainfall during the summer months shortly before and during the flowering of faba beans. Sclerotia are formed and carry the disease from year to year on crop debris in the soil. The spread within the crop takes place via spores that can travel over long distances.
RustTowards the end of flowering, scattered 0.5 to 1 mm large, orange rust pustules (uredimia) form on the upper and lower sides of the leaves, and on petioles and stems. Later, dark brown to black spots to 2 mm in size appear. Depending on the time and the degree of infestation, the development of the plant can be disrupted. Early infection may cause leaf fall.
Chocolate spotThe disease starts with small chocolate-coloured, splash-like round spots scattered irregularly on the lowest leaves. These spots are usually sharply demarcated by a reddish or grey-greenish margin. In severe advanced infection, the lesions grow, converge and darken. This all reduces the interception of light by the crop canopy. Infection at flowering can cause loss of flowers and young pods. Disease at this time can be particularly damaging as it impacts on both the canopy as the source of assimilate and the pods as the sink that forms yield.
RustThe spores require warmth for germination (optimum 20–25°C) which is why the disease usually only occurs in summer. Approximately 6–18 hours of leaf moisture from dew or rain are sufficient for this. Cooler nights with resulting high relative humidity favour the infection. Dense stands, late sowings, and sudden temperature rises with heat stress increase the risk of infection.
Chocolate spotThe occurrence of the disease is linked to humid conditions for several days. The optimum temperature for infectious spore germination is between 15–20°C with a relative humidity of at least 85–90%. The fungus needs at least 70% relative humidity and temperatures below 28°C for several days for the transition to a more aggressive phase leading to further spread within the crop (lesion growth). When the weather is favourable, a second spore generation can be formed 4–5 days after the initial infection. This can cause a second wave of infection in the stand. Chocolate spot disease is promoted by conditions that inhibit drying of the stands. These include heavy weed infestation, high plant densities, and locations sheltered from drying winds. In addition, poor plant vitality, caused for example by nutrient deficiency, soil compaction or viral diseases, reduces the tolerance of the disease. [caption id="attachment_19839" align="aligncenter" width="768"] Chocolate spot and rust.[/caption]
Economic impactRare severe uncontrolled infection of chocolate spot can cause total loss of the crop. In less exceptional circumstances, yield loss can reach 50% where conditions favour disease spread during and shortly after flowering. However, outbreaks of rust or chocolate spot in the late grain filling stage are unlikely to significantly reduce yield. Infections after flowering can still have an effect on yields, but chemical control at this time is economical only in the case of very heavy infestation. Infections during flowering pose the greatest risk to yield. Intervention with fungicides is justified from an economic viewpoint if the disease is present at the start of flowering and the weather is favourable for its spread. The difficulty of spraying tall crops after flowering without causing a lot of physical damage limits later control.
PreventionSeveral preventive measures can be taken to reduce the risk of disease and the need for direct intervention. These include growing faba bean no more frequently than one year in six, using seed from healthy crops, and using resistant cultivars. Further preventive measures include the incorporation of crop residues into the soil soon after harvest, maintaining a spatial distance from the previous year‘s cropped areas, early sowing (for spring-sown crops), and effective weed control as well as establishing the optimum plant density.
Chemical treatmentTebuconazole and azoxystrobin are approved for use to control rust and chocolate spot in faba bean in Germany. Tebuconazole is transported with the xylem water flow into the canopy. However, this also results in a dilution effect over time and is therefore active between 7 and 10 days. Tebuconazole has curative properties, especially in rust control, as it attacks the fungal mycelium. Azoxystrobin is systemic within the leaf and protects the plant by inhibiting spore germination. It must therefore be applied before the main infection event, but the effect lasts a relatively long time (up to 20 days). A combination of both active substances may be appropriate to use both modes of action. Repeated treatment may be required where the yield potential and disease risk is particularly high. Chemical treatment is particularly relevant when:
- the crop is flowering;
- the environmental conditions point towards a high disease risk and a high yield potential; and
- when the first symptoms of faba bean rust or chocolate spot are already visible during regular crop inspections.
Key practice points
- Prevention is preferable to cure: five years between succeeding faba bean crops and using field hygiene.
- Monitoring of weather shortly before and at the start of flowering helps detect situations with a high risk of early infection.
- Regular crop inspection under conditions that raise risk (persistent high humidity and temperatures around 20°C) helps identify cases where treatment is likely to be beneficial.
- The decision to spray the crop with fungicide depends on the risk of infection, the yield potential and potential loss versus the treatment cost, the crop development stage, and the prevailing and forecasted weather.
Lupins - cultivation and uses
Crop rotations with and without legumes: a review
Thermal treatment of faba bean for flavour improvement
OutcomeThis article provides useful information on how to denature flavour-affecting enzymes when developing food products from faba beans.
Off-flavours in faba beanVolatile compounds (e.g., aldehydes, alcohols, alkanes, ketones and aromatic hydrocarbons) are the sensory elements that affect the flavour perceptions of faba beans. Some of these compounds cause the undesirable flavour notes in faba bean foods produced using aqueous (wet) processing or fermentation. They emerge when the lipids undergo a process of degradation and oxidation catalysed by lipase, lipoxygenase (LOX) or peroxidase (POX). Lipid oxidation is important to consider as it affects the shelf life of food products. The process starts during harvesting, early processing and storage, when seeds are exposed to temperature, pH and moisture variations along with physical damage that degrade the physical barrier between the enzymes and the fatty acids (free or esterified), glucosides and amino acids within the cells of the bean.
Heat treatmentHeat treatment is an efficient way to inactivate or denature enzymes in any material made from faba bean. The treatment needs to be mild so it denatures these heat-sensitive enzymes without cooking the rest of the protein, as the cooked protein cannot be extracted to make a milk analogue or protein isolate. The target temperature is around 65–70°C. Possible heat treatments include microwaving, conventional ovens, steaming or kilning in the production line. Dehulling and milling increase the surface area of lipids exposed to the air and break the cells, increasing the access of enzymes to the lipids. This boosts the formation of unwanted flavour notes. Heat treatment applied prior to dehulling and milling is therefore beneficial. If the beans were dehulled prior to the heat treatment, then the heat-treatment step needs to follow immediately afterwards to prevent the formation of undesirable flavours.
SteamingHot steam denatures the enzymes of faba beans. The steam penetrates the cotyledons of the bean effectively. Pre-treatment of seeds with hot dry steam is an option for smaller mills. It is regularly used to inactivate the lipases of oats. It is therefore an existing process in many smaller mills that can be applied to faba beans. There are industrial-scaled steamers in Europe available for pre-treatment of grains. The settings on a flow-through oven have been optimised for this purpose in Finland. The timing and temperature have to be determined for each individual oven.
MicrowavingMicrowaves vibrate the water molecules and the vibration energy transforms to heat. The microwave waves penetrate the cotyledon even more effectively than steam. Research conducted at the University of Helsinki showed that microwave heating (at 950 W for 1.5 min) of small batches of faba beans inactivated the peroxidase and lipoxygenase. Achieving the same result on an industrial scale depends on the size of the equipment and sample size. Like conventional oven heating, the timing and energy level have to be determined for each individual oven. Microwaving has a short processing time and is able to spread high temperatures throughout the cotyledons, faster than conventional oven heating. The application of a microwave treatment for faba beans at an industrial scale would require a microwave-based conveyor belt system. This is not commonly used for pre-treatment of grains in Europe.
Testing for enzyme activityIn order to check whether the flavour-affecting enzymes have been denatured, the peroxidase activity can be tested. The minimum heat treatment resulting in inactive peroxidase will result in a product with optimal protein performance and without objectionable flavour. Peroxidase activity is more heat tolerant than lipase and lipoxygenase. If peroxidase activity is successfully inactivated, it is safe to assume that the lipase and lipoxygenase are as well. Peroxidase activity is generally analysed with a guaiacol-H2O2 method. The light absorbance of two solutions, one as the reacting solution and the other as blank, is measured using a spectrophotometer and the enzyme activity is calculated from the result. In the absence of a spectrophotometer, the enzyme activity can be visually assessed. This requires colour models to determine the colour development indicating the strength of the enzyme activity. Such a visual assessment is normally part of a miller or mill technician’s skillset. [caption id="attachment_19371" align="aligncenter" width="616"] Spectrophotometer model 1[/caption]
Key practice points
- There are several ways to denature flavouraffecting lipoxygenase and other endogenous enzymes.
- Millers provide important know-how for implementing the treatment effectively.
- Lipase, lipoxygenase and peroxidase activity can be tested using a guaiacol-H2O2 method by spectrophotometer or visual assessment
Further informationSharan, S., Zanghelini, G., Zotzel, J., Bonerz, D., Aschoff, J., Saint-Eve, A. and Maillard, M. N., 2021. Fava bean (Vicia faba L.) for food applications: From seed to ingredient processing and its effect on functional properties, antinutritional factors, flavor, and color. Comprehensive Reviews in Food Science and Food Safety, 20, 401–428.
Legume quality requirements for fish feed
OutcomeThe operation of an efficient market for grain legumes in aquaculture value chains helps growers and suppliers of grain legumes who are interested in supporting the fish feed industry. Understanding the requirements is the foundation of tailoring crop production and processing for this growing market. With this attention to quality requirements, European legumes can support the sustainable development of the European aquaculture sector. The sector has specialised requirements dictated by the physiology of farmed fish which, if met, can support premiums for farmers who meet these needs. This article presents the needs of the Mediterranean marine farmed fish, currently the top farmed fish produced in the European Union.
Basic nutritional requirementsMediterranean marine farmed (MMF) fish species are mainly carnivorous in nature and as such have high requirements for proteins and fats. Proteins are the main components of the fillet and fats are needed to cover the energy needs as well as the essential omega-3 and omega-6 fatty acids as much as possible. To achieve this, fish feed is typically 42–48% crude protein and 14–22% crude fat depending on the fish species and on the growth stage of the fish. MMF fish have a low capacity to digest carbohydrates and hence low requirements, which can be covered only by gelatinised starch from cereals. Crude fibre is indigestible and it is a critical limiting factor in selecting the raw material for fish feed (Figure 1). With these requirements met and with a proper feeding management on the farm, a high feed conversion rate (FCR) of 1.6 to 1.8 kg of feed fed per kg of fish produced is achieved in Mediterranean aquaculture today. Grain legumes can significantly contribute to the protein needs and to the starch fraction of the fish feed, reducing the inclusion of cereals such as wheat. In the early days of aquaculture, fishmeal provided the foundation of the protein component of the diet. Replacing the fishmeal with legume-derived protein is a cornerstone of the sustainable development of the sector. With this shift to legumes, which in contrast to fishmeal, all contain starch, the starch processing characteristics are important, especially for grain legumes such as faba bean and pea. Furthermore, content and quality of starch are critical points for the extrusion process as fish feeds are extruded feeds. In practice, this means that legume grains containing 25–45% protein and up to 40% starch could be included from about 8% to 25% in fish feed (Figure 2). In addition to a high protein content, a balanced amino acid profile that meets the nutritional requirements of the fish is crucial for replacing fishmeal. Of the 20 amino acids, 10 are essential that fish cannot synthesise. Therefore, so-called essential amino acids must be supplied by the feed (Figure 3). Comparing the amino acid profile of fishmeal as a benchmark to that of a number of legumes, it is clear that legumes can supply varied quantities of essential amino acids. However, the concentrations are lower than in fishmeal. Among the essential amino acids, lysine and methionine are the first limiting amino acids.
The special role of antinutritional factors (ANFs)Legumes have chemical constituents which form a defence mechanism in the plant against diseases and consumption by animals. While they are beneficial in protecting the plant itself and some contribute to the flavour for human consumption, these substances have negative effects on the performance of livestock. These are what we call ‘antinutritional factors’ (ANFs) with ‘protease inhibitors’ (PIs) being the main part. The most important PI is trypsin inhibitor (TI). Table 1 presents the trypsin inhibitor activity of different legume seeds. PIs impair protein digestibility and reduce the bioavailability of amino acids by inhibiting protein digestive enzymes. They can severely affect vital functions resulting in significant mortalities of farmed fish populations. In addition to direct impacts on the fish, there is a negative environmental impact due to increased nutrient emissions into the sea water. Indigestible plant components, such as non-starch polysaccharides present in high concentrations, increase faecal production and alter faecal properties. In addition to PIs, a variety of other ANFs are found in legume seeds (Table 2). ANFs such as non-starch polysaccharides (raffinose, stachyose), phytic acid, saponins and alkaloids derived from legumes and from cereal glutens may reduce palatability and feed consumption. Once consumed, they absorb water and increase intestinal motility and feed passage, resulting in reduced nutrient uptake and increased nitrogen excretion into seawater.
Processing is necessary to meet the requirementsGrain legumes must be processed to tailor them for use in fish feed. Dehulling removes the outer coat of the seeds and with it a large proportion of indigestible fibre and anti-nutritional tannins in the case of faba bean (Figure 4). At the same time, this increases the protein concentration of the raw material. The oil content of soybean is higher than required and oil extraction is performed, which further increases the protein concentration of soybean meal. Different processes have been developed to inactivate or to reduce ANFs below threshold limits. The thermal treatments have become the most used since they can gradually and precisely reduce trypsin inhibitor levels. However, heat treatment is costly and may damage the nutrients, including protein. Alternative options have been developed such as fermentation, ultrasound, gamma irradiation, germination and soaking. In general, thermal treatments such as cooking or/and extrusion as well as chemical and biotechnological approaches such as fermentation are the most effective treatments currently used. Finally, milling homogenises the material, increases digestibility and improves the quality of feed that is fed as pellet. Plant breeding also offers a solution to the challenge of ANFs. Cultivars of soybean with low TI content have been developed. The successful use of unprocessed soybean varieties with reduced content of TIs creates additional options for fish feed manufacturers while reducing the costs for thermal treatment. [caption id="attachment_19252" align="aligncenter" width="491"] Figure 4. Raw, dehulled and milled species Vicia faba (left) and species Lupinus albus (right)[/caption]
A range of grain legume species can be usedBased on these requirements, the aquaculture sector can use a range of protein sources. All the major grain legume species can be used successfully. Soybean is the main crop used. Soybean products (soybean meal, soy protein concentrate etc.) are the ingredients that have successfully reduced the use of fish meal in fish feed diets over the last twenty years. Faba bean meal and pea (mainly as protein concentrate) are also used in substantial quantities along with smaller quantities of lupin and chickpea. Pea, chickpea and faba bean successfully replaced wheat in seabass diets resulting in improved growth performance.
Basic quality requirementsThe quality requirements of MMF fish feed are determined by market status, processing mill specifications and nutritional performance. In particular, the quality parameters of legumes required for use in fish feed are:
- Protein content: Protein content is the most important characteristic in determining the competitiveness of a raw material compared with other protein sources. Legume grains and products with a high protein content are preferred.
- Protein quality: selection of species/cultivars with a balanced profile of essential amino acids and high protein bioavailability, i.e., protein that is easily hydrolysed in the presence of water and the digestive enzymes of the MMF fishes.
- Low levels of anti-nutritional factors: low levels of PIs to ensure good function of digestive enzymes and high dietary protein bioavailability.
- Content and quality of starch: This is a critical point for the use of legumes with protein concentrations below 35% e.g., faba bean and pea meal. Such legumes with high starch contents can be used in fish feed that include high protein raw materials like animal by-products to balance the protein level while covering the demand for starch for the extrusion process.
- Moisture content: Grain moisture content of legumes delivered to a feed mill should not exceed 12%. In addition to reducing the stability of the grain in store, the moisture content has a large effect on dehulling, which is necessary to remove the indigestible fibres contained in the seed coat.
- Impurities (foreign matter) content: The level of impurities in each batch (load) should not exceed 1.5% by weight. Impurities include fragments of the other parts of the crop, sand or stones, other seeds, etc. 1.5% is the upper limit to prevent price reductions due to contamination.
Transportation, warehousing and deliveryTransportation is done by truck, either in bulks or in big-bags of 1-tonne each. The following should be ensured:
- The load meets basic physical standards of moisture content and impurities.
- Proof that the truck and loading equipment has not been used for genetically modified soya in at least the last three shipments.
- Protection in store with temperatures below 22°C and relative humidity less than 75%.
- In accordance with the domestic and European legislation, quality management systems and feed safety (ISO 22000:2005 HACCP) accompanying documents or certificates of analysis for heavy metals, mycotoxins & aflatoxins, dioxines & PCBs, pesticides residues and microbiological content are required before the first delivery.
Further InformationFeedipedia. Animal feed resources information system, www.feedipedia.org
Risk management of downy mildew in soybean
BiologyThe plant pathogen P. manshurica exists currently in more than 30 different races. There is little relevant difference between races in virulence and response to management. This might change due to the ability of P. manshurica to rapidly adapt to the resistance genes in commercial cultivars. Resting spores survive from over-winter on leaf debris. They are also carried on seed. In most situations where soybean is rotated with other crops, the main infection route is infected seeds. An infected seed results in systemic infection of the whole plant causing stunting and mottling of the leaves. Symptoms are evident at all growth stages. Spores spread by wind in the growing crop. Initial disease development is favoured by a combination of frequent rainfall, heavy morning dew, high relative humidity, and moderate temperatures of 18–22°C. If this phase is followed by a prolonged dry spell, the infection risk is further increasing.
SymptomsThe most visible symptoms are 2–4 mm angular spots on the leaves. The initial symptoms are small pale green or yellowish spots which merge with time. On the reverse side of the leaf, a tan to grey covering forms, especially under wet and humid conditions. The early symptoms are present at the two (V2 grown stage) to three (V3 grown stage) trifoliate leaf stages. Younger leaves are more susceptible and infected leaves are commonly seen on the top of the plants. Pods may be infected without any outside symptoms, but the seeds inside are partly or completely encrusted with white mycelia and oospores. [caption id="attachment_19143" align="aligncenter" width="960"] Peronospora manshurica lifecycle on soybean seeds.[/caption]
Impact on crop developmentInfested seeds might suffer minor adverse effects during germination. Several experiments at different sites worldwide have investigated the potential yield losses by comparing fungicide-treated and untreated plots. Across those trials, severe disease infestation resulted in yield losses in susceptible cultivars of about 10% in extreme cases. There is also evidence that crop quality from fields which were planted with infested seeds is reduced in terms of seed vitality and protein content. In farming practice however, yield losses caused by downy mildew solely are difficult to measure accurately since yield losses are usually caused by several interacting factors (e.g. weather, pests).
Key practice points to manage the disease riskDowny mildew is currently not a major disease in European soybean crops. This is in most cases due to the relatively small soybean area and due to the short history of soybean production. Incidence is low even in regions with a relatively high proportion of soybean areas (e.g., Eastern Austria). Where it occurs, yield losses are low. However, this may change as the crop expands. The following measures will help preserving this positive situation:
Pathogen-free seedsThe use of healthy seed is the most important control measure. Seed infection levels can be tested by accredited laboratories and only pathogen-free seed should be used (see also below). [caption id="attachment_19147" align="aligncenter" width="1024"] Downy mildew on the front side of leaves.[/caption]
Cultivar choiceThe Austrian Descriptive Variety List provided by the Austrian Agency for Food Safety (AGES) provides a downy mildew resistance assessment for about 70 common soybean cultivars for growing in Europe.
Crop rotationGenerally, there should be at least two years, or better three years, between successive soybean crops in the same field to reduce the risk for disease infection through infested crop residues. This practise helps to manage downy mildew as well as other common soybean diseases unless infested seeds are planted.
Soil tillageTillage that speeds up the decomposition of infected material reduces the risk of a spread to future crops.
Sowing datesSowing soybean very early in the season at cool soil temperatures (<9°C) may result in a slow and poor establishment. This weakens the vitality of plants and increases potentially the risk of an attack by pests and diseases.
Avoiding mechanical damagesCracks in the soybean hull are potential entry points for fungi. Hence, mechanical damages during harvesting and transportation shall be avoided. Most essential are therefore proper harvester settings and gentle conveying applications in the storage.
Fungicide managementFungicide use is rarely economic in case of downy mildew in soybean. Experiences from studies in USA indicate that this disease is better managed through preventive measures (see above). [caption id="attachment_19151" align="aligncenter" width="768"] Downy mildew on the back side of the leaf.[/caption]
Resistance scoring of cultivarsThe Austrian Agency for Health and Food Safety (AGES) is the responsible body for seed certification to place it on the national and international markets of the European Union, the OECD market and the national seed market of Austria (Institute for seed and propagating material). As part of the three-year registration procedure, AGES assesses the performance of cultivars in the field in terms of yield, quality and resistance towards diseases and pests. AGES provides the data in the “Austrian Descriptive Variety List” which includes assessment for about 70 registered soybean varieties with a score system from 1 (trait strongly expressed feature) up to 9 (trait is not expressed). Link: https://www.ages.at/en/topics/agriculture/varieties/
Testing opportunitiesAGES in Vienna and in Novi Sad (Serbia), the Institute of Field and Vegetable Crops provide an analysis of seeds or leaves for Peronospora manshurica. Prices for an analysis may be up to 100 Euro per sample (excl. VAT). One kilogram of seed is needed for this testing procedure. Essential to achieve valid results is that a representative sampling has been conducted. Therefore, it is recommendable to take the sampling procedures of official seed certifications as a guidance. Links: Austrian Agency for Food Safety: https://www.ages.at/en/service/services-agriculture/analysis-of-seed-and-propagating-materia/ Institute of Field and Vegetable Crops Novi Sad: https://ifvcns.rs/en/research/laboratories/laboratory-for-seed-testing/
Choosing soybean cultivars
Progress to maturity (earliness): selection principlesDepending on the autumn conditions of a site, harvesting in September is generally preferred while ripening in October increases risks with weather. The growing season from crop emergence in May is therefore short and cultivars that mature quickly are required in most of Europe. The soybean is by nature a so-called short-day and warm-season plant. Flowering is suppressed in the long-day conditions of summer in most of Europe above 45°N unless the cultivar is insensitive to long days. Day-neutral cultivars have a combination of genes that allow flower initiation under the long-day conditions in Europe above 45°N. These cultivars initiate flowers as soon as the plant is large enough. The earliest then progress quickly through flower development, flowering, pod filling, and to maturity. Later-maturing cultivars develop larger plants and more crop biomass before initiating flowering. This results in a trade-off between earliness and yield potential. After sensitivity to day length, the second factor determining a cultivar’s suitability for a site is how rapidly the crop flowers and matures after flower initiation. Like with maize and sunflower, growth stops completely when temperatures fall to about 7°C. So soybean grows well in areas where other warm season crops such as grain maize and sunflower grow well. Day-neutral cultivars vary in the length of time taken to maturity which is measured as a product of time and temperature above a base temperature. This is the thermal time which is expressed as heat sums.
Progress to maturity (earliness): selection practiceThe categorisation of cultivars into so-called ‘maturity groups’ (MG) provides growers with a rough approximation of the suitability of a cultivar with respect to earliness for a given location. Cultivars are attributed to maturity groups based on field observations of new cultivars compared to established cultivars. There are 14 soybean maturity groups ranging from the cultivars that progress most rapidly to maturity (0000) to the latest (X). The latest can only be grown at low latitude, for example in the tropics. In contrast, all cultivars in maturity groups 0, 00, 000 and 0000 are daylength neutral and are basically adapted for use above 45°N. This is approximately the whole of Europe north of a line between Royan, Lyon, Venice, Zagreb, Novi Sad, Brasov and the Danube Delta. The 45th parallel is significant because mid-summer daylength above this exceeds 15.5 hours presenting a particular challenge to soybean as a short-day plant. [caption id="attachment_18962" align="aligncenter" width="1024"] Variation in earliness of soybean at the University of Natural Resources and Life Sciences Vienna.[/caption] The MG classification system is not precise but we can say that cultivars of the 000 MG are generally considered for cultivation in the main soy producing areas in Europe north of the Alps but also in cooler regions south and east of the Alps. The later 00 cultivars usually ripen safely in the traditional warmer winegrowing areas and the lowlands of the Rhine, Neckar, Main, and Danube valleys. Cultivars in 0 MG ripen only in the warmest areas north of the Alps. MG 0000 cultivars are the earliest and are therefore suitable for northern and maritime areas where cool conditions prevail, or as a second crop in warmer regions. Due to the trade-off between earliness and biomass accumulation, the yield potential of cultivars declines from the latest (X) to the earliest cultivars (0000). In warmer climates of southern and south-eastern Europe, cultivars categorised as in MG I and II with a higher yield potential may be cultivated. Recent breeding has been particularly effective in raising the yield potential of cultivars classified as MG 000. In practice, the constraint on the yield potential of the earliness in 0000 classified cultivars is significant. This may lead farmers to prefer cool season legumes such as faba bean in regions that require the degree of earliness provided by 0000 cultivars. Figure 1 shows the differences in suitability for soybean production across Europe. The effective cultivation of soybean for grain is practically impossible in the dark blue or dark orange regions. Cultivars of MG 0-0000 are generally suitable for cultivation in the areas shown in light blue and blue-green. Cultivars classified in MG I, II and III are suitable for the areas with darker green tones, yellow and light orange. Second cropping using earlier cultivars (00, 000) is also practiced in some warm areas where soybean may be sown after the harvest of winter cereals in June or early July, if water is available. Because the maturity group categorisation is only an approximate indicator of the speed of progress to maturity, some descriptive cultivar lists go further and indicate a number of more or fewer days for maturity compared to a cultivar serving as a reference. This is done in Switzerland, Czechia, France, Hungary and Poland. Description lists in Austria and Germany provide numbers to distinguish between relatively early, medium and late cultivars within a maturity group. In Austria, earliness ratings 2-3-4 are allocated to MG 000 and 5-6-7 to MG 00. These more precise ratings consider the impact of the local effects of temperature and water supply on earliness. Local testing of candidate cultivars to examine these fine responses helps in local selection. [caption id="attachment_22850" align="aligncenter" width="600"] Differences in suitability for growing soybean for grain across Europe. Source: Lidea Seeds[/caption] Because the maturity group categorisation is only approximate, some descriptive cultivar lists (Table 1) go further and indicate a number of more or fewer days for maturity compared to a cultivar serving as a reference. This is done in Switzerland, Czechia, France, Hungary and Poland. Description lists in Austria and Germany provide numbers to distinguish between relatively early, medium and late cultivars within a maturity group. In Austria, earliness ratings 2-3-4 are allocated to MG 000 and 5-6-7 to MG 00. These more precise ratings consider the impact of the local effects of temperature and water supply on earliness. Local testing of candidate cultivars to examine these fine responses helps in local selection. Table 1. Descriptive lists of cultivars
Publisher/link to cultivar descriptions (Country)
Austrian Agency for Health and Food Safety, AGES (Austria) Central Institute for Supervising and Testing in Agriculture, ÚKZÚZ (Czech Republic) Terres Inovia (France) Federal Plant Variety Office (Germany) National Food Chain Safety Office (NEBIH) (Hungary) Central Research Center for Cultivar Testing (COBORU) (Poland) Ministry of Agriculture, Forestry and Water Economy of the Republic of Serbia (Serbia) Agroscope (Switzerland)
Resistance to lodgingThe second selection criterion is the standing stability or the resistance to lodging. This currently varies from Grade 2 to 9 (with 1 = lodging risk very low to 9 = lodging risk very high) in the Austrian catalogue. Four grades are used in France (very low risk, low risk, medium risk, high risk). The risk of lodging is increased by lush growth enabled by a good supply of water. Therefore, cultivars that stand well are preferred where lush, vigorous growth is expected. As a trait, standing ability is often linked to determinate development that shortens the flowering period which in turn reduces the length of the growing period. This leads to early ripening which may in dry years mean a yield disadvantage compared to indeterminate cultivar types. Crop height is not decisive for resistance to lodging. Tall cultivars tend to have fewer pods placed close to the soil. This results in lower harvest losses, especially if a flexible cutterbar is not used. [caption id="attachment_18975" align="aligncenter" width="1024"] The exceptionally early 0000 soybean cultivar ‘Augusta’, so named because it matures in August in Poland.[/caption]
Disease resistanceResistance to sclerotinia stem rot is a valuable trait where the risk of this disease is high due to a specific microclimate or an increased proportion of susceptible species in the crop rotation (inter alia sunflower, oilseed rape, tobacco, many vegetable and salad species).
Rapid early growthRapid and vigorous early growth helps achieve early canopy cover suppressing weeds and reducing the risk of erosion. The current cultivars range from 5 to 9 on a 1 to 9 scale (with 1 = slow and 9 = fast). Cultivars with higher values are particularly useful in organic systems where the vigorous growth is valued for controlling weeds.
Protein contentForming protein is more demanding for the plant than forming carbohydrate. Therefore, as in wheat, there is a negative correlation between total grain yield and protein concentration in the grain. The optimum for the grower depends on crop trading arrangements. Achieving a minimum protein content may be critical where there are price deductions and supplements around a threshold, especially if the deductions below the threshold are greater than the supplements above it. To help, cultivars are characterised for expected protein concentration on a 2 to 9 point scale (9 being high). No cultivars with a protein concentration shown to be below the threshold in local tests should be selected were protein content is a marketing criterion. In the case of cultivation for on-farm use, protein yield per hectare may be a useful selection criterion. Since soybean oil is not well rewarded by the market and since high oil contents are not beneficial in feed, a high oil content may be rather a negative feature unless it is rewarded by an oil mill.
Diversifying cultivar useThe use of a range of cultivars spreads some agronomic risks. However, each cultivar should exceed a minimum area to ensure an economically viable marketing where cultivar choice is a marketing criterion. Using several cultivars that differ in earliness helps spread workloads at sowing and harvest. These may also be at different development stages if stress conditions impact on the crop.
Role of buyers and further useDepending on the product, specific quality requirements are common when growing soybean for food production. Food manufacturers that use soybean directly (e.g., for tofu or for milks) often have specific cultivar requirements. This reduces the cultivar options for these markets from the outset. Cultivar-related criteria are rarely a factor in marketing for animal feed (apart from its effect on protein concentration). Other cultivars are available for very special uses such as the production of edamame or natto with very specific qualities where low yields are accepted. Other characteristics such as seed weight (thousand grain weight), flower or navel colour are generally of no significance for cultivation or sale, unless otherwise contractually agreed in individual cases.
The role of seed qualityAs soybean seed is very susceptible to mechanical damage affecting the germination rate, the results of a simple on-farm germination test made a few weeks before sowing can be used to adjust seeding rates. This can also be used to negotiate price reductions with seed suppliers if the germination rate turns out to have fallen under the minimum rate for certificated seed of 80% (Germany, Austria, France). If it is known that seed of a desired cultivar is only available at a very low germination rate, it might be preferable to use a different cultivar. No seed with low germination rate should be used under difficult conditions (e.g. heavy, cold soil). In case of doubt, a germination test at cooler temperatures (cold test) may be helpful. [caption id="attachment_18979" align="aligncenter" width="1024"] Cultivar differences in earliness, vigour and stability.[/caption]
Using unregulated seedThe production and sale of seed is regulated in the EU to ensure that traded seed meets minimum standards of cultivar purity and quality. Farmers have access to a wide range of cultivars listed in the EU common catalogue of varieties which can be marketed in the EU. Seed of other cultivars can be purchased outside the EU for own use only using an importation license obtained from the national authority in charge of authorisation of seed. It is important to realise that the use of seed imported from countries where genetically modified crops are grown (e.g., from Canada or Ukraine) risks introducing traces of genetically modified seed which can cause serious trouble.
Official descriptions and tests of cultivars in EuropeNumerous new cultivars appear on the market every year after proving their performance in official and commercial tests. Their properties are listed in ‘descriptive variety lists’. These lists provide basic information to help growers select well-suited cultivars. In addition, the results of regional field tests are published every year in many parts of Europe. They are of special relevance to farmers in the respective regions and must be interpreted according to the local weather conditions in each year. Relative performance is subject to annual variation and so results over several years should be used, if available. These results are normally published by the regional agricultural development services. A selection is available on www.sojafoerderring.de.
- Make sure the cultivar is suited to the intended use or market.
- Use maturity groups (MG) as a guide.
- Opt for high resistance to lodging where lush growth is expected.
- Cultivars that have vigorous early growth help control weeds.
- Disease resistance is relevant only in higher rainfall areas or in crop rotations with a high proportion of sunflowers, rapeseed, vegetables, tobacco etc.
- Consider protein content where it is a marketing criterion.
- Consider oil content where it is a marketing criterion and avoid high oil contents for own, regional or organic feeding.
- Criteria such as seed size, flower and navel colour are usually not relevant.
- Use several cultivars that vary in earliness where large areas are grown.
Further informationDeutscher Soja Förderring, www.sojafoerderring.de European Commission. EU plant variety database, https://ec.europa.eu/food/plant/plant_propagation_material/plant_variety_catalogues_databases/search/public/index.cfm?event=SearchForm&ctl_type=A
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Phosphorus fertilisation of faba bean
OutcomeEnsuring a good supply of nutrients, in particular phosphorus, from the soil is the nutritional foundation of high yield. Yield increases after P fertilisation of up to 40% are reported under farm conditions in low P index soils. Good fertilisation practice secures this yield potential while minimising the risk of phosphorus loss to water. Placement of P close to the seed in low P soils supports good P utilisation and ensures optimum use of the investment in fertiliser.
Rate of phosphorous applicationThe above reported evidence on phosphorus supply being particularly important for high yielding faba bean crops grown under low soil-P supply has important implications for production practice in Ireland and in other countries. Faba bean yielding above 6.5 t/ha is common in Ireland. What are the implications for practice and what are the principles that determine these practices? Soil analysis for plant available P is the basis of planning phosphorus applications to all crops. This involves laboratory analysis of representative soil samples following national or regional guidelines. The Irish soil index system categorises soils into one of four soil index levels based on the soil test P result (Morgan extraction). Table 1 shows the P recommendation for each soil index for faba bean.
Soil pH and phosphorous uptakePhosphorus exists in several different forms in soil and the occurrence of each of them depends largely on soil pH. Plant available inorganic P is most abundant when the pH is between 6 and 7. A whole-farm liming regime that maintains soil pH between 6.5 and 7 over the rotation ensures that the soil phosphorus is most available to crops.
Application time and methodBeans as with other legume crops require P for crop growth, from early development to the end of grain fill. Plants require relatively small amounts of P during establishment but have high P uptake during rapid canopy development. Ensuring the availability of P at the establishment phase is essential. This can be from soil reserves or applied P in low P sites. Phosphorus is relatively immobile in soil and so applications on low index soils must be made at or before sowing to influence plant growth (Table 2). Placement of fertiliser in close proximity to the seed (either by placement in the same furrow as the seed or by side banding at planting/seeding) is an effective method of fertiliser application, especially to provide a starter source of nutrient for early crop nutrition and growth. Depending on the soil P status, fertiliser may be broadcast (ideal for higher P sites), with or without subsequent incorporation, or placed close to the seed at planting (which is beneficial on low P sites). Where soil phosphorus levels are adequate, faba bean shows little response to timing and method of application. Where P requirement is high, placing all the P with the seed at sowing may increase the risks of damaging the emerging plant. Incorporation/placement of P at sowing provides a good basis for high yields, especially in low P-soils.
Key practice points
- Research observations indicate that faba bean is responsive to good P fertilisation due to the effect of phosphorus on nodule formation and function. This impacts indirectly on the nitrogen supply from biological nitrogen fixation.
- As a pre-requisite for the effective application of P fertilisers, soil samples must be taken and analysed according to national or regional standard practices to determine the soil phosphorus levels/indices following national guidelines.
- Application methods should take into account soil phosphorus index and the rate of phosphorus to be applied. Placement of P close to seed is important on low P index soils. This is achieved using combined drilling where the fertiliser is placed in or beside the seed row. On high P index soils, placement close to the seed is less important and broadcasting before or after sowing can be used.
Further informationWatson, C. A., Reckling, M., Preissel, S., Bachinger, J., Bergkvist, G., Kuhlman, T., Lindström, K., Nemecek, T., Cairistiona F. E. Topp, C. F. E., Vanhatalo, A., Zander, P., Murphy-Bokern, D. and Stoddard, F. L., 2017. Chapter Four - Grain legume production and use in European agricultural systems. Editor(s): Sparks, D. L. Advances in Agronomy, Volume 144, 235–303. doi.org/10.1016/bs.agron.2017.03.003 Grant, C. A., Flaten, D. N., Tomasiewicz, D. J. and Sheppard, S. C., 2001. The importance of early season phosphorus nutrition. Can. J. Plant Sci. 81(2): 211–224. Havlin, J. L., Beaton, J. D., Tisdale, S. L. and Nelson, W. L., 2014. Soil Fertility and Fertilizers. An introduction to nutrient management. 6th ed. Prentice Hall, NJ. Henry, J. L., Slinkard, A. E. and Hogg, T. J., 1995. The effect of phosphorus fertilizer on establishment, yield and quality of pea, lentil and faba bean. Can. J. Plant Sci. 75: 395–398. The Fertilizer Association of Ireland in association with Teagasc, 2019. The efficient use of phosphorus in agricultural soils. Technical Bulletin Series – No. 4, February 2019 (Booklet). www.fertilizer-assoc.ie/wp-content/uploads/2019/02/The-Efficient-Use-of-Phosphorus-In-Agricultural-Soils-Tech-Bulletin-No.-4.pdf The Fertilizer Association of Ireland in association with Teagasc, 2017. Precise application of fertiliser. Technical Bulletin Series – No. 3, May 2017. www.teagasc.ie/publications/2017/precise-application-of-fertiliser.php The Fertilizer Association of Ireland in association with Teagasc, 2015. Soil Sampling - Why & How? Technical Bulletin Series – No. 1, October 2015. www.fertilizer-assoc.ie/wp-content/uploads/2015/10/Fert-Assoc-Tech-Bulletin-No.-1-Soil-Sampling.pdf
Feeding lucerne to dairy cows
OutcomeThe inclusion of lucerne in a grass or maize-based forage ration reduces the need for feeding high protein rapeseed and/or soybean meal to high-performance dairy cows. The beneficial effect depends on the protein content of the grass or maize silage that is replaced and the stage of cutting of lucerne which will determine its nutritional value.
Forage quality of lucerneThe protein concentration of lucerne silage (18-22% of dry matter) is significantly higher than that of maize silage (about 8%) and good quality grass silage (14%). This benefit is off-set by a lower metabolisable energy content. Farmers can use lucerne to substitute grass silage or maize silage without affecting animal performance. This provides the foundation for reducing supplementary feeding costs. For example, replacing 3 kg dry matter of maize silage with lucerne silage balanced by extra cereal to raise the starch content reduces the need for rapeseed meal by 1.3 kg. Lucerne is more palatable than grass and maize silage. This means that the lower energy content of the lucerne is partly compensated by higher forage intakes. Milk output is maintained while supplementary protein feeding can be reduced, although the starch component of the concentrate supplement will need to be increased where lucerne replaces maize silage or other whole-crop cereals. In supporting milk production, lucerne is similar to red clover (another legume forage) as a high-protein forage that is fed together with grass or maize silage, although lucerne leads to improved milk quality compared to red clover. Lucerne has a greater buffering capacity than maize silage and can have a beneficial effect on rumen pH. Replacing some grass silage with lucerne silage in milking cow diets has been shown to increase dry matter intake, milk production and quality (Table 1). This requires formulation of diets that contain similar levels of metabolisable energy and protein. The inclusion of lucerne in the silage mix significantly increased dry matter intake and the higher forage protein content enabled a reduction in supplementary protein feeding at similar levels of milk output. Milk output per unit dry matter intake declined due to the lower digestibility of the lucerne. For overall feed costs, inclusion of lucerne in a diet can help save on bought in protein concentrate costs assuming the protein in the lucerne silage is greater than the protein in grass silage. The stage of maturity of the lucerne crop when cut for silage affects the balance between yield and nutritional quality. The protein and metabolisable energy content of the silage is high when cut at the flower bud stage. Delaying cutting to the flowering stage increases yield but decreases quality. A compromise between yield and quality is cutting at between the 10 to 30% flowering stage (See Harvesting and storing lucerne - legumehub.eu). Short forage chop length can increase feed intake in dairy cows. However, a short chop length can increase the risk of sub-acute ruminal acidosis.
Feeding strategiesEffective use of lucerne to replace other forages in the diet for milking cows is highly dependent on the nutritional value of the lucerne and the quality of the forage it replaces. Increasing lucerne silage in the ration will reduce the requirement for purchased protein, particularly where it is replacing whole-crop cereal or maize silage (although more cereal grain may be required to balance the ration for starch). The relative prices of these feeds determine whether including lucerne can be a cost-effective option. Home-grown high-protein forages, such as lucerne, become more competitive as the cost of imported protein ingredients increases. Lucerne silage has higher levels of calcium than grass silage. As is the case with all high calcium feeds, feeding lucerne to cows before calving might increase the risk of hypocalcaemia (milk fever due to calcium deficiency) when milk production starts around calving time. This is because high calcium intake before calving affects the hormonal mechanisms that control calcium mobilisation, increasing the risk of low blood calcium levels after calving.
Key practice points
- Lucerne can substitute grass silage in dairy rations without compromising animal performance.
- Depending on the forage quality that lucerne replaces in the diet, savings can be made in supplementary protein costs.
- Starch levels need to be maintained when substituting maize silage or other whole-crop cereal with lucerne.
- Stage of cutting is an important consideration for forage quality but also to aid regrowth and persistency. Cutting at the bud stage will maximise quality but it is advised to leave until the early flower stage to gain extra yield and maintain plant health.
- A shorter chop length increases forage intake.
Drill-seeding of soybean
OutcomeGood crop establishment is the key to high soybean yields. Practical experience has shown that drill seeders are suitable for achieving high yields. Drill seeders sow in narrow rows which contribute to an early canopy closure which increases the competitiveness of the crop against weeds and reduces the risk of soil erosion.
Drill-seeding in practiceDrill seeders are widely used for arable field crops, especially small-grained cereals. Drill seeders are also known as solid crop seeders because the rows are narrow. The seed is placed in the soil at the set depth in rows using hoes or disks (known as coulters) drawn through the soil. Drill seeding is a robust technology that can also be used to sow seed into minimally cultivated soils. While the seeding depth and distance between rows is set, the distance between individual seeds within the rows is not. The spacing of the plants in the row depends on the seed flow from a seed tank to the coulters. The older machines use metered gravity feed while more modern machines use compressed air to carry the seed. Drill seeders are generally lower-cost and are more widely available than precision seeders. They are also operated at higher speeds resulting in faster sowing. This results in a good combination of effective crop establishment at a low cost for machinery and labour. Drill seeding has better results on small, uneven fields as the area is more evenly filled with plants. The disadvantage of drill seeding is the lack of control over seed spacing within the row as well as greater variation in seed depth compared with precision seeders.
Basic functional componentsSeed metering and seed transfer within drill seeders determine the distribution of seeds in the row and seed rate. Mechanical (gravity) or pneumatic (compressed air) mechanisms are used. Mechanical seed meters supply and distribute seeds using gravity flow. The metering mechanism is situated directly under a seed hopper with one meter for each row. These meters are driven by a single shaft that extends to the full width of the seeder. The shaft is rotated by a land wheel that links the flow of seed to the forward speed. The fluted roller is the most widely used mechanism. This type of meter is adjusted for different sized seeds and seeding rates by regulating a flap on the fluted roller and by adjusting the velocity ratio, i.e., the speed of rotation of the fluted roller in relation to the forward speed of the drill. Most mechanical seed drills are 3–4 meters wide. Pneumatic seed distribution systems use compressed air to transfer seed from a central tank to the coulters. Hydraulically powered onboard fans create an active air stream which passes seeds to a distribution head. This splits the seed flow into the individual delivery tubes that open into the coulters. There are two types of pneumatic seeders: those that have a flow meter for each tube, coulter and row and those that have a single central metering mechanism before the seed flow is split between the tubes to the coulters. The main advantage of the pneumatic drills is that a wider working width and forward speed is possible because the air flow can carry seeds several meters on either side of the tractor. There is however a higher mechanical impact on the seed which can reduce the germination rate of soybean. The air flow can also remove powdery inoculants that have not been applied using adhesives. [caption id="attachment_18487" align="aligncenter" width="395"] Amazon grain drill, with gravity seed metering/delivering mechanism, provides row width of 150 mm.[/caption]
The coulter optionsCoulters open the slot in the soil and place the seed at the required depth. There are two most common types of coulters: anchor and disk (single disk or double disk) and various combinations of these. The choice depends on typical soil texture and amount of plant residues on the soil surface. Disk-anchor combinations are sometimes used where the first coulter improves the seedbed by cutting crop residues and loosening heavy soil and the second seeding coulter opens the slot for the seeds.
Covering the seedsThe seeder should place the seeds in the slot on a firm moist soil layer and cover the seeds evenly to the required depth. There should be good contact between the seed and the soil. This is achieved using press wheels or rollers. This operation improves seed contact with the soil, with the moisture of the lower soil layers and promotes uniform germination. As covering devices press wheels, rollers, chains, drags and packers are used. Seed drills need to be calibrated to ensure the right amount of seed is released per unit area. This seed needs to be evenly distributed in the rows at a uniform depth. Careful calibration of the seeder ensures that the target seeding rate is achieved. The forward speed needs to be limited to 6 km/hour so that the coulters have time to open the slot and place the seed evenly. Excessive speed leads to uneven seeding with gaps in parts of rows and bunching of plants in other parts. A good drill should guarantee that the seeds are placed evenly at the same depth in good contact with the soil and that the seeds are well covered with a layer of soil for better germination.
Special agronomic aspectsDrill seeders were developed for sowing cereal crops, traditionally with narrow row spacing (12-25 cm). In practice, drill seeding of soybean using narrow rows results in following benefits and limitations:
Narrow rows speed up canopy closureThe yield potential of any crop depends on the amount of light intercepted by the green canopy from crop emergence to maturity. Narrow row spacing reduces the time to canopy closure supporting this fundamental driver of yield. Early canopy closure also reduces evaporation of water from the soil, suppresses weeds, and reduces the risk of soil erosion. The rapid canopy cover may also stimulate pods setting higher up in the plant. This makes harvesting easier and reduces losses of low pods. [caption id="attachment_18495" align="aligncenter" width="431"] Seedlings of soybean, narrow-row sowed in 150 mm rows.[/caption] Research conducted in the northern steppe zone of Ukraine (Shepilova, 2009) showed that crops sown at 15 cm row widths reached full canopy closing when the plants had 3-5 nodes. Crops with 30 cm rows reached full canopy closure at budding to flowering (Growth Stage R1-R2). Crops with 70 cm rows did not close until flowering and pod formation (Growth Stage R2-R3). A similar effect is shown in Table 1. As a robust seeding technology, drill seeding opens up the possibility to use different soil tillage systems for growing soybean:
- Seeding in a conventional tillage system with a seedbed consisting typically of a firm lower layer at a depth of 3-4 cm, covered by a loose upper soil layer.
- Seeding in a reduced or conservational tillage system without a specially prepared seedbed. This reduces soil disturbance, evaporation and fuel consumption. Additionally, seeding into a mulch of plant debris from the previous crop is enabled which helps to reduce the risk for soil erosion.
Spatial placement of soybean seedsCompared to precision seeders, drill seeders are susceptible to variation in the placing of the seeds in terms of depth and homogeneity within the row. This is happening especially if driven fast and where there is a large amount of crop residue. Gaps and doubling of seeds could occur also. It is not critical for soybean if it does not exceed 5% of the seeds sown. It is important to set up the drill correctly and to monitor its operation periodically. [caption id="attachment_18521" align="aligncenter" width="600"] Unevenness of sowing depth in drill seeding.[/caption]
Further informationJoseph, J., 2016. Benefits for soil & yield with direct drilling approach. Farm Herefordshire. www.youtube.com/watch?v=XBdruGJzkYA (accessed 19.11.2020) Agriculture XPRT. Seed drills. Equipment for crop cultivation in Europe, website: www.agriculture-xprt.com/crop-cultivation/seed-drills/products/location-europe (accessed 19.11.2020) Pöttinger Landtechnik GmbH. Seed drills, website: www.poettinger.at/en_in/produkte/kategorie/sm/seed-drills (accessed 19.11.2020)
Winter pea in south-east Europe
OutcomeThe experience and knowledge accumulated is applicable across the south-east Europe region. Pea for forage or grain establishes a nitrogen-fixing symbiosis with the pea nodule bacteria Rhizobium leguminosarum biovar viciae, which is naturally widespread in the European soils. This symbiosis is important for maintaining soil fertility. The inclusion of winter pea in crop rotation as a precursor of other crops reduces the nitrogen fertiliser use. The early harvest of winter pea provides the possibilities for additional economic use of the agricultural land. The intensive growth and development of green mass occurs in April and May when rainfall is sufficient to ensure an intensive growth without irrigation. Forage crops reach mowing maturity at the end of May. As an over-wintering crop, winter pea protects soil from wind and water erosion.
Pea in BulgariaPea has been grown in Bulgaria for centuries. It became a widespread crop in the 19th century, when its cultivation expanded in northern Bulgaria as a forage crop, and in southern Bulgaria as a vegetable crop. The cultivation of pea for both dry grain and forage became popular in the 20th century. For many years, the efforts of breeders and farmers were concentrated on forage pea grown in mixtures with cereals. Gradually, the area occupied by pea increased and reached 54,000 ha in 1967. It decreased to 10,000 ha in the period 1975 to 1980. Significant growth of the areas occupied by peas was observed during the period 1983 and 1988 when it was recognised as a perspective forage crop and the areas reached 150,000 ha. The reform in agriculture, which started in 1989, disrupted cultivar maintenance and seed production and caused a decline in production to only 10,000 ha in 1993. Interest of private farmers has increased since 2000 and the area of forage, grain and vegetable pea has recovered to over 50,000 ha. Vegetable pea accounts for about 14% of the area.
Winter pea cultivarsThere are three Bulgarian cultivars of winter fodder peas which are preferred by farmers: Mir, Pleven 10 and Vesela.
- Mir yields 33 to 55 t/ha of forage or 2.5–3.0 t/ha of grain. It is characterised with rapid growth and development in early spring. It is a great precursor for tobacco and forage maize. It performs well on all types of soil but does not tolerate acidic saline or poorly drained soils.
- Pleven 10 is a forage cultivar that grows 140 to 200 cm tall. It is particularly frost tolerant. It is ready for mowing in late May - beginning of June. Yields of forage are 33–35 t/ha. Grain yields amount to 2.0-2.5 t/ha.
- Vesela is grown for forage and dry grain for feed. It matures as a forage crop in early May. Yields of forage are 33–35 t/ha. Grain yields account for 2.5 to 3.5 t/ha.
Key practice points
Preceding cropThe basic requirement for the preceding crop is to leave the soil clear of weeds and ready for soil tillage. Suitable preceding crops are cereals (wheat barley, triticale, rye and oat). Sunflower is less suitable and maize is unsuitable. Pea does not tolerate sowing after itself and other legume crops. It is recommended to produce pea not more frequently than once in five years.
Soil tillageShallow cultivation (5–10 cm) after the harvest of the preceding crop conserves soil moisture while stimulating the germination of weeds and volunteer cereals. This is usually followed by ploughing and conventional cultivation. Reduced tillage is an option especially with dry soils and where continued drought is expected, for example in southern Bulgaria. This commonly comprises disk harrowing at 10–15 cm deep.
Sowing date and ratePea should be sown by mid-October in northern Bulgaria and by early November in southern Bulgaria. Winter cultivars are sown with 120–150 germinating seeds per m-2 or 160–180 kg/ha. The peas are sown in a row (row spacing 12–15 cm) at a depth of 6–8 cm depending on the seed size and soil type. Rolling is required.
FertilisationProductive pea crops require a good supply of phosphorus and potassium. Applications of moderate amounts of phosphorous (60–80 kg/ha P2O5) and potassium (40–50 kg/ha K2O) are commonly used. It should be applied with basic tillage in autumn. Phosphorus fertilisation contributes to a better development of the root system and increases disease resistance. A small amount of nitrogen (20–30 kg/ha) incorporated during soil tillage before sowing can be useful as a starter in poor soils when the symbiosis with rhizobia is slow to establish.
Plant protection measuresThe most economically important pests in pea seed production are the pea weevils Bruchus pisorum L. and Tychius quinquepunctatus L. They are widespread throughout the country and can cause damage of the crop up to 100%. Timely treatment of crops with insecticides is important for successful control of these pests. The initial treatment should be done at the beginning of flowering. Economically important diseases are Ascochyta pisi and Erysiphe pisi. Immediate ploughing of crop residues after harvest to avoid spore dispersal from diseased plants is recommended against diseases.
HarvestThe optimal stage for harvesting for forage is at the end of flowering/early pod setting to get the best combination of forage yield and quality. When the harvest time is delayed, dry matter yield can increase while the forage quality declines. Harvesting for grain is difficult because these forage-type varieties lodge, ripen unevenly, and the pods and seeds are easily damaged by moisture. Traditionally, the grain is dried in the sun after harvest. The seeds are cleaned and stored.
More informationAs part of the European project „Legumes Translated“ ID 817634, www.legumestranslated.eu, aiming to promote the cultivation and use of leguminous crops in Europe – the units of Bulgarian Legumes Network /BGLN/ Fodder Institute crops -Pleven, Agricultural Academy /AA/, Dobruzhanski Agricultural Institute /AA/-General Toshevo, Institute Plant Genetic Resources, Sadovo offer basic seeds of Bulgarian varieties of fodder pea, various materials related to its cultivation.
Feeding faba bean to poultry in practice
Home-grown faba bean for organic poultryUwe Brede and Babett Löber grow field bean cultivar Bilbo on their organic farm on Domaen Niederbeisheim, near the German city of Kassel. They keep laying hens and young hens, together about 30,000 birds. 100% organic feed rations is a matter of course for them. Faba bean is a valuable home-grown source of protein. They took over the farm in 1995 and switched to organic farming in the same year. Non-inversion (ploughless) tillage was introduced soon after organic conversion. „Today we can till our light limestone soils very efficiently and quickly“, reports Mr Brede. „The minimal tillage system with power harrowing instead of ploughing has established itself and has become an indispensable part of our business.“ Uwe Brede is a pioneer of organic agriculture. He is fully committed to a cyclical flow of nutrients on the farm. Organic seed production and the use of 100% organic feed rations in his laying and young hens is part of this.
Participatory plant breeding and cultivar maintenanceUwe Brede co-founded the Bäuerliche Ökosaatzucht e.G. as a cooperative. One focus of the co-operative is the systematic identification and maintenance of crop cultivars for organic farming. This includes maintaining and multiplying the field bean Bilbo. Wheat, barley, rye, triticale, spring barley, oat and grain legumes are multiplied on the Niederbeisheim estate on around 90 hectares (ha). In addition, in cooperation with a seed company for fine-seeded legumes, red clover is propagated on 20 ha. In total, the farm has around 150 ha of arable land and 27 ha of grassland. There is capacity for around 10,500 laying hens and for the rearing of around 18,000 young hens. “The development of this operation was driven by good local conditions and favourable market developments“ says Mr Brede. “This produces a high-quality organic fertiliser for our crops giving us a good nutrient balance from the closed nutrient cycle“ All eggs are marketed with a partner company. There the eggs are sorted, packed and marketed. The laying hens have been fed 100% organically for years with a consistently good laying performance. A needs-based amino acid supply in the organic rations is important. With purely home-grown protein feed components, this can only be achieved by upgrading the rations using valuable feed components such as oil cakes (Table 1). Dehulling of faba bean enhances the value of the home-grown protein feed components further. This takes place in the on-farm mill where the hulls are separated from the seed and removed via the air classifier. And it works very well: de-hulling increases the protein content from 24 to 36%.
Local faba bean for conventional egg productionManfred Hermanns keeps 54,000 hens in barn, free range and organic systems. He mixes the feed himself and also uses faba bean as a domestic source of protein. Mr Hermanns is convinced of the advantages of faba bean. „Faba bean is home-grown, has short transport routes, is GM and gluten free, and the crop supports pollinating insects. But it wasn‘t as simple as it sounds right from the start. When I tried to feed field bean to the hens a few years ago, it was a flop. The hens rejected the feed due to the high content of the poorly digestible glycosides vicin and convicin.“ Farmers are now growing new cultivars such as Tiffany, which are low in glycosides and are more palatable for hens. Mr Hermanns started cautiously with a 1% inclusion of faba bean which he increased gradually to about 7% (Table 2). The raw protein content and the content of the amino acids lysine, methionine and threonine were more favourable than expected. This has a positive effect on the health of the laying hens. It took the farmer several years to optimise the ration. The reward is a healthy flock, hardly any problems with feather pecking and pest infestation. And if there are any problems, which can also be caused by external influences such as high tempera-tures, Mr Hermanns uses the opportunity to immediately vary the composition of his own feed ration. „The feed is better and even cheaper,“ says the farmer happily. He has acquired a small feed mixer consisting of three different mills and a conical mixer. He grows 36% of the animal feed himself. Except for soybean, the rest comes from other farms in the region. Mr Hermanns would like to replace the soybean with sunflower meal in the long term. Due to the regional production concept, the eggs cost on average two cent more than comparable eggs from other farms. „This is only possible because we communicate the added value of our products to our customers and because they want to support our idea,“ explains the farmer.
Further informationBellof, G., Halle, I. and Rodehutscord, M., 2016. Ackerbohnen, Futtererbsen und Blaue Süßlupinen in der Geflügelfütterung. UFOP-Praxisinformation. Jeroch, H., Lipiec, A., Abel, H., Zentek, J., Grela, E. and Bellof, G., 2016. Körnerleguminosen als Futter- und Nahrungsmittel. DLG-Verlag, Frankfurt.
OutcomeSuccessful soybean harvesting is about recovering the highest proportion of the grain with the best possible quality and purity at the optimal time.
Harvest timeHarvest should start when the seed moisture drops to 13–15%. The rate of drying primarily depends on temperature and precipitation. The moisture content in the seeds can differ within a day by 5%. If the seeds are too damp in the morning, they can dry during the day. The moist phase persists longer as the nights become longer and colder. Wind accelerates drying. If after mid-October the seed moisture content is higher and no better weather in sight, it is also possible to start harvest up to 20% moisture, but then drying is required which involves additional costs. Losses increase and seed quality is reduced with delayed harvest. The following situations can prevail:
- The crop has developed under favourable conditions, leaves fall down during maturation and, within a few days, seed moisture drops to the optimal level for harvest.
- The plants are exposed to stressful conditions such as drought and/or high temperature leading to early senescence. Most of the leaves remain on the plants, while the pods and seeds are mature and ready for harvest.
- The crop is mature and not harvested on time. Losses increase due to diseases and pod shattering. This especially occurs if the pods are exposed to several cycles of wetting and drying.
PrinciplesCareful adjustment of the combine harvester is essential for a successful harvest. Soybeans have several characteristics that determine the optimum harvest practices. First, the earliest pods often form close to the ground, which means that the combine table and knife have to be guided close to the ground. A level, firm, and stone-free seedbed is a great help. The crop itself affects drying rates. A mature soybean stand is more open than a cereal stand and can dry rapidly during the day. As the pods are fragile, repeated cycles of drying and wetting increase pod shattering and loss of seeds. Timing is therefore critical if the weather is unsettled. The ideal grain moisture content is about 13%. For seed production it is about 15% because seeds at this moisture content are less vulnerable to mechanical damage. Waiting until the crop has dried down to about 12% reduces the cost of drying after harvest. The seed moisture content must be below 15% for short term storage and about 12% for long term storage. The characteristics of the soybean itself influence the combine setting and operation. Soybeans are large and heavy but the seed coat is fragile. The grains need to be protected from the threshing forces and mechanisms, especially if the grain is used for seed production. The first protection mechanism is the crop itself. Keeping the combine well-filled with crop material protects the seed. This means ensuring the combine forward speed is high enough to prevent an empty or nearly empty threshing mechanism. Very dry seed is fragile, so the second protection mechanism is harvesting before the seed becomes too dry. Harvesting soy with a seed moisture content below 12% increases the rate of damaged beans. 15% is an optimum for seed crops. The third mechanism is adjustment of the drum speed and related concave clearance. The pods are easily threshed and so a very gentle threshing mechanism can be used with a low drum speed and open concave. This also reduces fuel consumption of the combine. A high fan speed can be used to gently separate the seed from the straw. Lastly, the seed should be handled gently in the grain tank, in the augers and during transport by not emptying tanks and augers completely and by minimising auger speeds and drop heights. [caption id="attachment_18214" align="aligncenter" width="1024"] Pouring soybean grain onto a tractor trailer[/caption]
Key practice points
- Harvest should be adjusted to the field and crop conditions. This involves appropriate adjustments of the harvester forward speed, airflow, drum speed, concave clearance, and sieves.
- The crop bulk protects the seed so the forward speed should be maintained for sufficient material flow through the threshing mechanisms to reduce damage to the seeds.
- The cutter bar should be kept close to the ground (3–6 cm). To allow cutting close to the soil surface, forward speed should be kept moderate at no more than 5 km/h. Stones or an uneven surface can limit the lowest possible cutting height as damage through stones or contamination with soil should be avoided.
- Ideally, a flexible cutter bar should be used that allows gliding on the ground and removal of stones and such, reducing losses by about 10% to a minimum.
- The header reel should be carefully adjusted to reduce contact with the crop. Reel speed revolutions should be synchronised with the harvester speed – usually 25% faster.
- Drum speed should be kept to 400–600 rotations per minute, depending on seed moisture.
- The sieves should be adjusted according to the seed size.
Further informationTaifun-Tofu GmbH, Landwirtschaftliches Zentrum für Sojaanbau und Entwicklung, 2020. Threshing soybean properly. https://youtu.be/ojoqDzMNQGo Legume Hub. www.legumehub.eu Taifun Soy Info 13: Threshing soybeans correctly Taifun Soy Info 14: Flex cutting bars
Harvesting and storing lucerne
OutcomeAttention to detail results in a good balance between yield and nutritional quality as affected by the stage of maturity. This also supports crop persistence and helps reduce weed invasion.
Harvesting lucerneHarvesting lucerne is different to harvesting grass in several important respects. The date of harvest is less critical for nutritional quality compared with grass. The digestibility and palatability does not decline after the ideal harvest date as much as in grass. However, the crop’s fragile leaves are susceptible to loss during handling. A lower sugar content compared with ryegrass requires greater attention to achieving good fermentation. Good harvest management of this perennial legume is about achieving an optimum balance between harvest yield and allowing the crop to build up root reserves for over-wintering so that the crop persists from year to year. Optimising harvesting means balancing several objectives: harvest yield, nutritional quality, crop persistence and crop health. For established crops in their second and subsequent years, harvesting at the flower bud stage results in a high protein content. Delaying harvest to the flowering stage results in a higher yield but with a decline in quality. Harvesting when 10 to 30% of the flowers are open is a reasonable compromise between yield and quality. Repeated early cutting (before flowering) affects plant health, reduces persistency and increases weed invasion. There is sufficient build-up of food reserves in the roots for good regrowth and over-wintering by the time the crop starts to flower. As a general rule, a crop should be allowed to reach 50% flowering at least once each year. Once established, similar to perennial ryegrass, lucerne can be cut a number of times through the growing season, generally from May onwards. In a four cut regime (about late May, early July, mid-August, and October), the first two cuts together account for about 70% of the annual yield while the last cut accounts for only about 10%. October harvesting reduces the root reserves for over-wintering. The decision to harvest in October is critical for allowing the plant to build up root reserves for the winter. Unlike grasses, where the growing point is at the plant base at soil level, lucerne’s growing points are higher up on the stem. Therefore it is important to leave a 7 cm high stubble. In addition to enabling rapid regrowth, this relatively high stubble also aids wilting, drying and crop handling. Avoiding loss of the leaf material is a priority in crop handling because the leaves account for up to 70% of protein. About 90% of the vitamins and minerals are stored in the leaves. Turning and swathing should be done when the crop is damp, for example early in the morning. [caption id="attachment_17645" align="aligncenter" width="400"] Lucerne sowing[/caption]
Conservation and storageConserving lucerne requires more attention to detail than grass. The forage can be difficult to ensile due to the lower sugar content. Higher dry matter is needed for clamped silage (around 35%). This reduces the risk of clostridial fermentation and butyric acid production that reduces feed intake, production, and is harmful to general animal health. The use of an additive i.e. acids, molasses or homofermentative bacteria is also essential to promote the lactic acid producing bacteria for effective fermentation. Wilting (partly field-drying) lowers the moisture content and increases the concentration of sugars allowing the silage to stabilise quickly. This reduces the amount of additive needed. There is a potential for mold spoiling lucerne silage at higher moisture levels, especially in big bale silage. Due to the more fibrous stems, the lucerne is more difficult than grass to compress to exclude the oxygen. Therefore a higher dry matter (40-50%) is needed for baled silage. However, over-wilting with more than 50% dry matter makes compression more difficult. The fibrous stems also require at least four wraps of plastic to prevent them piercing the wrap and allowing oxygen into the bale. There a number of simple tests that can be used to estimate forage dry matter content. The first is hand squeezing a small ball of lucerne cut into 1–2 cm lengths. The dry matter is about 30–40% when the ball falls apart slowly with no free moisture and little moisture on the hand. When the ball springs apart quickly the dry matter is over 40%. This can also be estimated with a microwave oven. A large handful is weighed to the nearest gram in a microwavable container and placed in the microwave oven along with a cup of water. The sample is dried in 3 minute intervals at high power until it begins to feel dry, then dried at 30 second intervals with the sample being weighed after every interval. Once the weight of the sample does not change this final weight is recorded. The percent dry weight is calculated from the final dried weight as a percent of the original weight. Lucerne silage takes approximately six weeks, a similar amount of time for grass silage. [caption id="attachment_17649" align="aligncenter" width="1024"] Lucerne silage[/caption]
Key practice points
- Forage yield, quality, re-growth and persistency depends on the timing of cutting. Leaf cutting until the early flower stage to gain extra yield and maintain plant health.
- A 7 cm stubble helps rapid regrowth and the drying of the swath.
- Leaves are easily damaged or shattered when drying, reduce mechanical movement of the cut crop.
- Use additives to aid fermentation.
- Baled silage requires a higher dry matter for good preservation than clamped silage.
Mites in soybean production
OutcomeSpider mite populations can reach damaging levels very quickly. Infestation can reduce the soybean yield by 40–60%. The protection of the crop from stresses, such as herbicide damage, reduces the risk of damaging infestation. Where chemical control is permitted, detection of outbreaks in the early stage helps to implement effective control measures. Monitoring should start in late June and continue throughout July and August. Early treatment decreases damage and spot treatment of localised patches of infection near field boundaries may be sufficient.
Biology of the spider mite and the two-spotted spider miteMature spider mite females are 0.5 mm long and egg shaped. Summer generation females are yellow green, while winter generation females are more red. Males are smaller and yellow, with a sharp-pointed abdomen. Eggs are oval and approximately 0.14 mm in diameter. Freshly laid eggs are glassy-white. The eggs become more yellow later. The first immature stage (larvae) is around 0.5 mm long and yellow, with three pairs of legs. The following nymphal stages and adults have four pairs of legs. The two-spotted spider mite is a cosmopolitan species and can feed on a range of host plant species. Adults are the size of salt grains and are greenish-yellow to brown, with two black spots. Morphological traits, biology, damage and control are similar to Tetranychus atlanticus.
BiologyMites have 10 to 14 generations per year. Overwintering females lay their eggs on wild plants in spring. Mites migrate from wild plants on field margins to crops and create colonies very fast. These are usually covered with a fine silky web which protects them from predators and adverse weather conditions. Colonies consist of individuals of all growing stages. This makes chemical control more difficult. Populations rapidly increase during June. Mites reach their highest abundance in July and August. Daytime temperatures over 30°C greatly increase the risk of damage. Natural enemies and diseases of the mites that counter the build-up of infestations, spread in cooler humid conditions. [caption id="attachment_16684" align="aligncenter" width="906"] Mites attack. Photograph: IFVCNS[/caption]
Crop monitoring and detectionA 10x magnifying lens is very helpful for the visual detection. The easiest way to detect an infestation is to tap a leaf over a sheet of white paper on which the mites are visible as dark, moving dots. Webs on the leaf surface indicate an infestation. The mites migrate into the soybean crop particularly if the vegetation in field margins is mown or otherwise disturbed. Neighbouring alfalfa fields pose a particular risk, as alfalfa is a preferred host plant of mites. The mites use the wind and their nets for transport, flying like a balloon (‘ballooning’). If possible, vegetation adjacent to the soybean field should not be mown during dry periods because this can stimulate migration into the crop. Mites pierce leaves to suck sap causing yellow dots which expand and merge over time. Infested leaves become yellow or bronze. Some leaf drop follows. Webbing may also be present under the leaves. Mites usually populate the upper young leaves but in some cases of heavier infestation, whole plants can be covered with web. Damaged plants are smaller, their transpiration increases and photosynthesis is less effective. They also mature earlier, producing fewer pods and lower yields. Symptoms of infestation can easily be confused with water stress, improper herbicide application, or leaf diseases. The first symptoms occur at field edges, and later the whole field can be infested.
ControlSpider mites are controlled by various natural enemies. These are mainly predatory mites (e.g., species of the Phytoseidae), lesser mite destroyer/spider mite destroyer (Stethorus punctillum), the common green lacewing (Chrysoperla carnae), brown lacewings (Hemerobiidae) and predatory bugs (Orius spp.). These beneficial insects should be supported to avoid mass reproduction of spider mites. In addition, all cultivation measures that reduce drought stress will help. These include attention at sowing to establish a crop that competes against weeds avoiding severe herbicide use that stresses the crop. Rain is the farmer’s best friend in case of spider mites because the spider mite population usually collapses when rain follows a warm dry period. The mites are then attacked by the fungal antagonist Neozygites floridana. The fungus requires 12–24 hours of weather conditions with less than 29°C in combination with 90% humidity to spread throughout the whole population. Infected mites can be recognized by their waxy and dull structure. They die after 1–3 days. There are no synthetic acaricides approved for the control of mites in soybean in the European Union. Outside the EU, there are only a few acaricides available for chemical control based on chlorpyrifos, dimethoate (both organophosphates), bifenthrin (a pyrethroid) or abamectin (avermectins). Some of these pesticides are available for use in European countries outside the EU. These are often not able to effectively control an infestation. [caption id="attachment_16688" align="aligncenter" width="439"] Tetranychus urticae, 200x magnification. Photograph:
State Horticultural College and Research Institute
- Cultural and biological control is the cornerstone of managing these pests. Good crop establishment (sowing date, crop densities etc.) can reduce the damage of this pest.
- It is important to prevent weeds since a wide range of weed species host mites in the crop. These plants can host several generations and provide the starting point of infestations.
- Irrigation has beneficial effects on soybean. It also helps control mites.
- The crop is particularly sensitive to infestation at flowering (R1 and BBCH stages 60 to 69). This period is critical for yield formation. Where chemical control is an option, a decision to treat should focus on protecting the crop at this time. Although infestation in later growth phases results in increased pod shattering, the negative effects on the yield are not as high.
- Regular and systematic field observations is an important part of crop protection planning.
- The economic threshold for implementing a curative treatment is when 50% of plants with symptoms are observed on field borders, or when there are on average more than 5 specimens on one leaf.
- For chemical control, acaricides registered for this purpose are legal in some European countries outside the EU. In cases of severe attacks, spraying may be repeated after 7 to 10 days. The use of larger quantities of water than is used for other spraying purposes combined with higher sprayer pressure enhances the effect because the colonies inhabit the back of the leaves. Treatments during the hottest daytime periods should be avoided.
- The same acaricide should not be used twice in the same season because spider mites are able to quickly develop resistance.
- When chemical control is used the lowest effective amount of the respective pesticide, using equipment that is properly calibrated, should be used.
- Following the above-mentioned suggestions will greatly assist in managing spider mites populations. Other activities that will assist include encouraging predators and beneficial insects and monitoring mite populations.
Feeding pea to poultry
Experience at the Vogt organic farm: peas for laying henThis farm in Lower Franconia in Germany converted to organic in 1987. Starting with 60 laying hens, the flock have been kept in a repurposed cowshed with an adjoining orchard meadow since 1991. The flock is now 500 hens. The entire home-grown pea crop is fed to the laying hens. Every eight weeks, a mobile milling and mixing plant comes to process and blend the components with a protein supplement called Concentrate Bio-L-Konz 40 from the Kaisermühle. This protein supplement consists mainly of soya cake, sunflower cake, corn gluten and minerals. By using the higher quality components such as husked spelt, naked oats and peas, the proportion of this highprotein supplement can be reduced from the recommended 40% to 30%. [caption id="attachment_16620" align="alignleft" width="435"] Laying hen. Photogaph: Werner Vogt-Kaute[/caption] Depending on the age of the hens, some lime and salt must then be added. While wheat and naked oats can be crushed, spelt and peas must be milled finely. „Coarse fragments of pea hull or husks are sorted out by the laying hens,“explains Kornelia Vogt. The goal is a feed with 0.3% methionine and an energy content of around 10 MJ/kg. No oil is added to the feed so that the energy content remains low and the laying hens are encouraged to eat more. With this ration, the laying performance reaches just over 90% in the young hen (about 25 eggs/month), but then remains constant between 80 and 90% for several months. The laying hens remain on the farm for 16 to 18 months. The stability of the egg affects egg handling, storage and use. While the proportion of pea used here is relatively low, experience at Vogt shows that even this low inclusion boosts performance while replacing cereals. „Including pea reduces the cereal grain content and the associated non-starch polysaccharides which are anti-nutritional factors for poultry” the plant manager explains. Up to 20% peas are fed in the ration, which can also be tannin-containing, violet-flowered varieties „We have never observed a decrease in laying performance when using tannin-containing cultivars at these inclusion rates. But we limit the inclusion of faba bean with pea to 10%.“ Martin and Inge Ritter from Ostheim vor der Rhön in Lower Franconia converted their business to organic farming in 2000. At conversion, the farm business was based on a dairy herd and a livery service for local horse owners. The livery service was retained but the dairy herd was sold off. New enterprises were established and son Tim joined the company as a trained poultry farmer. Two turkey sheds were built. The turkey chicks are first reared by a specialised organic rearing company until they are about 40 days old. From then on, 2000 animals are kept in the open shed with free run of the adjoining woodland. Family Ritter also likes to bring male turkeys together with female, because the flock is calmer as a result. The breed used is chosen to meet market demand. Some of the turkeys are marketed from the farm, as are a few broilers and geese.
Feeding turkeys is demandingThe turkeys receive a complete feed in the first stages of life to give them the best start. Turkey chicks are the most demanding of all poultry species in terms of feeding. In the later growing and finishing phase, Martin Ritter uses his own feed mix produced by a mobile grinding and mixing plant. The home-grown ingredients are rolled to give a coarse-textured feed. At the beginning of the finishing period, the proportion of the home-grown component is 10%, at the end 50%. Peas are always included. „Tannin-containing pea is used without any problems,“ explains the plant manager. „Feed conversion efficiency declines towards the end of the fattening period when the animals eat endlessly. It is therefore important to reduce the cost of the ration. Weight at slaughter will not be affected by reducing the ration quality if the daily gains in the initial phase are adequate.“ [caption id="attachment_16613" align="alignnone" width="436"] Turkeys on open pasture. Photograph: Werner Vogt-Kaute[/caption]
Further informationBellof, G., Halle, I., Rodehutscord, M., 2016. Ackerbohnen, Futtererbsen und Blaue Süßlupinen in der Geflügelfütterung. UFOP-Praxisinformation. Jeroch, H., Lipiec, A., Abel, H., Zentek, J., Grela, E., Bellof, G., 2016. Körnerleguminosen als Futter- und Nahrungsmittel. DLG-Verlag, Frankfurt. Demonstrationsnetzwerk Erbse/Bohne, website: www.demoneterbo.agrarpraxisforschung.de Union zur Förderung von Öl- und Proteinpflanzen e.V., UFOP: www.ufop.de/medien/downloads/agrar-info/praxisinformationen/tierernaehrung/
Feeding quality of faba bean for poultry
Nutritional componentsThe nutritional components of faba bean are summarised in Table 1. Grain legumes are used in livestock feed primarily for their protein content. Faba bean with 12% moisture is about 26% protein. In addition to crude protein, faba bean is high in carbohydrate, especially starch, contributing to the metabolisable energy. The nutrient content of faba bean is influenced by growing condition and the cultivar used. The protein digestibility and amino acid profile are the major determinants of the feeding value. The protein is highly digestible. On the amino acid profile side, faba bean is rich in lysine, but relatively low in methionine and cystine. The limiting factor for the use of faba bean in poultry rations is the low content of methionine. The mineral contents are similar to that of cereals. Faba bean contains less phosphorus than soy and rapeseed meal. The phosphorus is partially bound to phytic acid which reduces phosphorus absorption without the addition of the enzyme phytase.
Anti nutritional factorsAnti-nutritional components adversely affect digestion and animal health. Vicine/convicine and tannins are the most important antinutritive substances in faba bean, followed by protease inhibitors, lectins and saponins. For poultry feed, only low vicine/convicine faba bean cultivars should be used. Using standard vicine/convicine containing cultivars, there is a decline in performance when inclusion rates exceed 10%. In addition, tannins found in the seed coat of dark seeds from dark flowering cultivars reduce food intake due to their bitter taste. Cultivars containing tannins are easily recognisable by their purple flowers, but also by a black spot on the stipules and a darker grain colour. Tanninrelated effects on protein digestibility and enzyme binding play a role only at high inclusion rates (>20%). Other anti-nutritive ingredients such as protease inhibitors, lectins and saponins are present in only small amounts in faba bean and have no adverse effects at typical rates of inclusion.
Feed valueThe feeding value depends on the quantity of protein, the nutritional quality of that protein, and the energy feed values determined by the digestibility of the nutrients. Protein quality in poultry nutrition is characterised by the content of the most important essential amino acids, namely lysine, methionine and cysteine, threonine and tryptophan. The digestibility of the amino acids is also important, which varies both, between amino acids and between different grain legumes (Table 2).
Maximum rate of inclusion of faba bean in poultry feedThe quantities used depend on age and performance phase of the poultry. The use of faba bean for poultry is limited by the methionine content (Figure 2). But the levels of vicine/convicine of cultivars also limit use to maximum 10% in feed ration (Table 3). Nevertheless, the methionine content of field bean is more than 20% higher than that of most cereals. This means that faba bean can be used to replace other protein-rich components, e.g., oilseed meals and corn gluten, and synthetic amino acids. A higher proportion of own or domestic raw materials can be used. [caption id="attachment_16578" align="aligncenter" width="550"] Laying hen Lohmann Brown.[/caption]
Further informationBellof, G., Halle, I. and Rodehutscord, M., 2016. Ackerbohnen, Futtererbsen und Blaue Süßlupinen in der Geflügelfütterung. UFOP Praxisinformation. Jeroch, H., Lipiec, A., Abel, H., Zentek, J., Grela, E., Bellof, G., 2016. Körnerleguminosen als Futter und Nahrungsmittel. DLG-Verlag, Frankfurt.
Bugs in soybeans
Intercropping of grain pea with cereals
OutomeIntercrops usually have a higher yield than the average of the same crops grown separately. The information here can help farmers optimise the use of this type of intercropping. These intercrops are resilient and require no nitrogen fertiliser or herbicide applications. The cereal component prevents the pea component from lodging. Intercrops can make a contribution to low input systems in particular.
Steps to successful intercropping of pea and cerealsCultivar selection: Semi-leafless short-stemmed grain pea and barley are ideal intercropping partners. Experience shows that a seed mixture that combines 80% of the pure stand density for pea and 40% of the pure stand density for the cereal is a good general starting point. This ratio may be adapted to individual experiences with growth patterns of different cultivars. Semi-leafless spring and winter pea cultivars are suitable and possible matching combinations are shown in Table 1. Long-stemmed pea cultivars are often also used for forage production. Rye or triticale is a suitable partner crop for these tall pea cultivars. The pea component of the seed mixture is lower than with shorter semi-leafless pea due to the strong vegetative growth. A combination of 20–40% of pure stand seed rate for tall pea and 70% of pure stand density for rye/triticale gives good results. No field work is required between sowing and harvest due to the strong growth of the crops. It is important that the pea and cereal cultivars mature around the same time. Finding the suitable cultivar combination (same maturity) and adapted seed mixing ratios can be accomplished by setting up simple strip trials. [caption id="attachment_16382" align="aligncenter" width="768"] Forage pea (Szarvasi) and rye[/caption] Crop rotation: Producing legumes more frequently than one year in five increases the risk of soil-borne diseases that cause ‘legume fatigue’. A legume-based intercrop must be treated as a pure-stand legume crop in the rotation. Seedbed preparation: Due to the rapid development of ground cover, these cereal/pea systems are especially suitable for sowing into mulch. Otherwise, pea establishes best in well-consolidated seedbeds. Soil compaction and crust formation on the soil surface reduces plant growth and prevents good development of root nodules that fix nitrogen. Ploughing or other deep loosening may be required for heavy soils. Spring sowing on very heavy soils may require autumn ploughing, otherwise ploughing in February is sufficient. Light cultivation that preserves soil crumb structure reduces the risk of soil crusting. Application of green manure or compost is also possible. Sowing: We use a simple gravity-fed seed drill as is traditionally used for cereals. The seed must be pre-mixed before filling the drill tank. The homogeneity of the mixture should be checked regularly during sowing. Combine drills (with two tanks) can be used to sow the pea and cereals separately. Typical cereal row spacing is suitable with a sowing depth of 3–4 cm. Seeding time: Peas/cereals can be sown in autumn or spring at sowing time of the pea. Autumn sowing reduces the impact of spring and summer drought, particularly if pea flowering time occurs before drought hits the crop. This is a drought avoidance strategy and the longer growing season from autumn sowing tends to stabilise yields. The ideal sowing date in autumn is one that produces well established but small plants by winter (3–4 leaf stage). Spring sowing takes place as early as possible at the beginning of March, so that the crop can use the moisture accumulated during the winter. Pea seedlings tolerate slight frost events around -4°C. Weed control is usually not needed, but a high weed pressure can be controlled by harrowing in early stages. Tall pea/rye mixtures are particularly competitive and a completely weed-free crop is often achieved. Fertilisation: No nitrogen fertilisation is needed. Nitrogen fixed by the pea has only a small effect on the cereal. However, the cereal has been reported to stimulate nodulation. Harvest: The peas are ready to harvest when a fingernail can no longer penetrate the grain at a moisture content of 12–15%. The pods are particularly brittle and susceptible to shatter when the air is dry. Harvesting in the morning and evening, when humidity rises, reduces pod shatter. The optimum combine setting is a compromise between minimising damage to the pea seeds while harvesting as much of the cereal grain as possible. This involves the following considerations for setting the combine harvester:
- Careful use of the reel to avoid pod shattering.
- Use the crop lifters with tips pointed downwards.
- Low drum speed.
- Open concave to avoid damaging the pea grain.
- Adjust grain sieves to the pea.
- Low fan speed compared with a pure pea harvest to avoid losing the cereals (they are smaller and lighter).
- Where relevant, retraction of the vario-table with the cutter bar kept close to the table auger.
Crop performanceYield: The ratio of grain legumes to cereals in the harvested crop fluctuates for different reasons, depending on how stresses impact on the crop. The proportion of pea in the crop of autumn-sown grain pea mixtures in many trials (from 2009–2015) ranged between 30 and 80%. The crop yield (pea and barley) varied between 3 and 6 t/ha. The yields of mixtures of forage pea and rye ranged between 2.5 and 5.2 t/ ha and the share of peas in the harvest varied between 26 and 80% (Trials 2016 and 2017). [caption id="attachment_16378" align="aligncenter" width="681"] A semi-leafless protein pea and barley mixture.[/caption]
Balancing the effectsAdvantages
- More resilient cropping systems and reduced risks of crop failure. If one component fails, the second partly compensates.
- More efficient use of ressources (nutrients, water, light, land).
- No need for nitrogen fertilisation.
- Weed suppression thanks to fast and dense ground cover.
- Defence against or distraction of potential pests.
- Attraction of beneficial insects.
- Easier harvest thanks to the greatly reduced lodging and weed infestation.
- Matching the cultivars is not easy.
- Simultaneous maturation within mixed crops is required.
- Cereal quality might be inferior due to nitrogen deficiency.
- Additional expenditure in post-harvest processing to separate the pea from the cereal.
Key practice points
- Mixing of seeds of intercropping partners before sowing, prevent de-mixing during sowing (occasional control of seedtank), sowing depth according to grain legume needs.
- Start with proposed seed mixing ratios and adapt to local conditions or varieties.
- Make sure separation of the harvested crop is possible.
Further informationAlföldi T., 2015: „Anbau von Mischkulturen - Körnerleguminosen mit Getreide“, FiBL. www.youtube.com/watch?v=gAYNXCw2CiE FiBL Switzerland ongoing, Mischkulturen. www.bioaktuell.ch/pflanzenbau/ackerbau/mischkulturen.html Hauggaard-Nielsen, H., Jørnsgaard, B., Kinane, J. and Jensen, E. S., 2007. Grain legume–cereal intercropping: The practical application of diversity, competition and facilitation in arable and organic cropping systems, Renewable Agriculture and Food Systems: 23(1); 3–12.
Faba bean, grain pea, sweet lupin and soybean in poultry feeds
This UFOP publication provides an overview of the composition, feed value and possible uses of grain legumes in poultry feed. In particular, the results of feeding trials over the last ten years have been taken into account. For faba beans, both white-flowered and variegated varieties are considered in the brochure. For peas, the focus is on white-flowered varieties, as these dominate the market and are particularly suitable for poultry feed in terms of nutritional physiology. The considerations for lupins refer to the sweet blue and white lupins. The sweet yellow lupins currently play no role in cultivation. However, due to their nutrient composition, they could become attractive again for poultry feed in the future. Full-fat soybeans and soybean cake made from them are the most important feedstuffs from domestic (European) soybean cultivation.
Soybean processing systems
Growing spring-sown pea in south-east Europe
OutcomeThe information set out here helps the development of the pea crop in Bulgaria providing an example for the wider south-east Europe region. Pea is a crop with high plasticity which helps it to overcome adverse weather conditions. It uses soil resources very effectively. In addition, it is able to establish a nitrogen-fixing symbiosis with Rhizobium leguminosarum biovar Viciae bacteria to fix up to 150 kg N/ha and to add 45–70 kg N/ha to the soil for the benefit of the following crop. Thus, pea leaves a nitrogen soil reserve for the subsequent cereal crop. Pea is easy to insert into rotations with cereals (e.g., wheat) as pure stand or in mixture with a companion cereal (i.e., triticale, oat, barley). In addition, in a rotation with cereals, pea contributes to breaking the cycle of cereal diseases. It also ripens early giving the possibilities for a second crop later in the year.
Pea in BulgariaPea has been grown in Bulgaria for centuries. It became a widespread crop in the 19th century, when its cultivation expanded into northern Bulgaria as a fodder crop, and in southern Bulgaria as a vegetable crop. The cultivation of pea for both dry grain and forage became popular in the 20th century. For many years, the efforts of breeders and farmers were concentrated on forage pea grown in mixtures with cereals. Gradually, the area occupied by pea increased and reached 54,000 ha in 1967 and decreased to 10,000 ha in the period of 1975 to 1980. Significant growth of the areas occupied by pea was observed during the period between 1983 and 1988 when it was recognised as a perspective forage crop and the areas reached 150,000 ha. The reform in agriculture, which started in 1989, disrupted proper cultivar maintenance and seed production and caused another decline in production to only 10,000 ha in 1993. Interest of private farmers has increased since 2000 and the area of forage, grain and vegetable pea has recovered to over 50,000. Vegetable pea accounts for about 14% of the area. [caption id="attachment_16258" align="aligncenter" width="700"] Seeds from spring pea in the region of Pleven, North Bulgaria.[/caption]
Spring pea cultivarsThe biological characteristics of pea enable it to be grown as a spring and winter crop (Table 1). “Pleven 4” and “Kerpo” are important Bulgarian forage cultivars for spring sowing. They were bred in the Institute of Forage Crops in Pleven in northern Bulgaria. Two grain cultivars (Mistel and Kristel) were bred in the Dobruzhanski Agricultural Institute, General Toshevo, North Bulgaria. Three grain cultivars (Teddy, Amitie and Picardy) come from the Institute of Plant Genetic Resources, Sadovo, southern Bulgaria. The intensive growth and development of spring pea cultivars occur during the period May-June, when rainfall is sufficient to ensure an intensive crop development without irrigation.
- Kristal: plants are well-branched and leafy, height 67–87 cm, vegetation period 110–130 days. The 1,000-seed weight is 280 g and grain yield amounts to 4–5 t/ha. The cultivar is medium early.
- Mishel: height 50 cm, vegetation period 110–125 days. The weight of 1,000 seeds is 202 g, it is small-seeded with a grain yield of 3.5 t/ha.
- Pleven 4: plant height 100–120 cm. The pods are medium-sized usually with 4–6 seeds. The mass of 1000 seeds weighs 180–190 g. The cultivar is medium early with good resistance to powdery mildew and ascochitosis. It is grown for green mass and seeds. The vegetation of the cultivar is 90–100 days and yields 3.6–3.8 t/ha.
- Kerpo: leafy, medium in height at 60–80 cm. The leaf is compound with a maximum leaflet number of 6 that are medium in size. The 1000-seed weight is 240 to 250 g, i.e., it is small-seeded. Depending on the climatic factors, the cultivar begins flowering in late April – early May and ripens in the second half of June. The vegetation period varies from 80 to 90 days. The grain yield is 3.7–5.0 t/ha.
- Amitie: short growing period from 68 to 84 days. Seed yield is 3.2–4.5 t/ha, used for grain feeding.
- Picardy: grain yield amounts to 3.8–4.5 t/ha. Growing period is 68 to 80 days. The cultivar is suitable for dry grain for fodder and processing.
- Teddy: used in the canning and processing industries (dietary flours and additives), because of its good taste. The vegetation of the cultivar is 68 to 80 days and seed yield 3.8–4.5 t/ha.
Key practice points
Preceding cropThe basic requirement for the preceding crop is to leave the soil clear of weeds. Pea is not compatible with pea and so should not be grown more often than one in five years.
Soil tillagePloughing followed by conventional tillage is most commonly used and provides the essential compaction-free 30 cm layer. Reduced tillage should be used where severe summer drought is expected. Although adapted to a range of soils, the preferred ones of pea are those aerated, with good water holding capacity, moderate lime content and a pH between 6.5 and 7.5.
Sowing date and rateThe most suitable time for sowing spring pea is February to beginning of March (for some south-east regions it could be end of January to middle of February). Thus, the plants use the accumulated winter moisture and develop a strong root system that makes them more resistant to summer droughts. Delayed sowing reduces yields. The recommended seed rate – that can vary depending on soil characteristics and cultivar - is 100-120 germinating seeds per m-2 or 240–280 kg/ha for large seeds and 120–180 kg/ha for small seeds. The peas are sown in a row (row spacing 12–15 cm) at a depth of 6–8 cm depending on the seed size and soil type. Rolling is required.
FertilisationPea productivity is closely dependent on phosphorus and potassium fertilisation. Moderate amounts of phosphorous (60–80 kg/ha P2 O5) and potassium (40–50 kg/ha K2O) are required. It should be applied with basic tillage in the autumn. Phosphorus fertilisation contributes to a better development of the root system and also increases disease resistance. A small amount of nitrogen (20–30 kg/ha) incorporated during soil tillage before sowing can be useful as a starter in poor soils when the symbiosis with rhizobia is not yet established.
Plant protection measuresSpring pea is a weak competitor of weeds. For this reason, rapid seedling emergence, adequate crop density, pre- and post-plant tillage, and herbicides help to reduce weed pressure. If appropriate, chemical control of both grass and broadleaf weeds is possible using a range of pre-and post-emergence herbicides. The most economically important pest of crop grown for grain is Bruchus pisi. The successful treatment of this pest is the timely application of insecticide to crops. Economically important diseases are Ascochyta pisi and Erysiphe pisi. Immediate ploughing of crop residues after harvest to avoid spore dispersal from diseased plants is recommended against diseases.
HarvestThe optimal stage for harvesting for green mass is at the end of flowering/early pod setting, to maximise forage yield and quality. When the harvest time is delayed, dry matter yield can increase, but simultaneously the forage quality declines. Most often the seeds are harvested by direct combining, which is applied when more than 70% of the beans are ripe, in dry weather, but not in the hottest hours of the day. Peas must be harvested as soon as possible. Otherwise, grain losses are significant. After threshing, the grain is dried in the sun, cleaned in high humidity and what will be stored for a long time is fumigated. Seeds should be stored in dry, ventilated rooms. [caption id="attachment_16260" align="aligncenter" width="1024"] Spring pea for forage in the region of Pleven, North Bulgaria.[/caption]
More informationThe members of Bulgarian Legumes Network (Fodder Institute Crops-Pleven, Agricultural Academy; Dobruzhanski Agricultural Institute Toshevo; Institute Plant Genetic Resources, Sadovo) offer basic seeds of Bulgarian cultivars of fodder pea, various materials related to its cultivation.
Growing lucerne in cool climates
Resourcing the cropPlant breeders have adapted lucerne to grow in a range of climates. Cultivars vary in the levels of winter activity or dormancy. There are two main types grown in Europe: the Provence or southern types which grow more prolifically, and the Flemish or northern types which are more winter hardy with a more intense winter dormancy. Being a legume, lucerne fixes nitrogen (N) through bacteria (rhizobium) in nodules on the roots. To ensure good nodule formation, the seed can be inoculated with rhizobium before being drilled (See Inoculation of soybean seed for how this is done for soybeans). Lucerne is not competitive in its early stages so it is usually grown as a monoculture. It is essential to control broad-leaved weeds, especially during establishment when the young plants are vulnerable to shading from weeds. There is a limited range of herbicides available for weed control and professional support should be sought from suppliers. A herbicide-free solution is to grow lucerne in a mixture with low-growing grasses such as meadow fescue (Festuca pratensis) and timothy (Phleumpratensis) if the aim is to maximise lucerne production. Taller grasses such as cocksfoot (Dactylis glomerata) can be used if a grass- lucerne mixture is required. The grasses help control weeds, especially at the establishment phase. Lucerne can also be under-sown with spring cereals that are harvested as a forage crop. The use of short-straw cereals sown at about half the normal seed rate helps the establishment of lucerne when under-sown. As the bacteria in the root nodules fix atmospheric nitrogen, little fertiliser nitrogen should be applied (only up to 30 kg/ha during establishment). Keeping soil mineral nitrogen low encourages nodule production and activity. Lucerne has a high demand for phosphorous (P) and potassium (K) fertiliser and the required application will depend on the soil index (as shown in table 1). Limiting slurry applications (up to 30 kg N/ha) after the last cut balances the provision of P and K with the avoidance of over-supplying N. This slurry replaces some of the P and K taken off in the crop and can improve dry matter yields. The crop requires a minimum period of undisturbed stem growth and root development in the first year of establishment. For this, the first cutting should take place after flowering, as the plants need to build up root reserves for the next regrowth. Each re-growth after cutting draws on the root reserves. The last cut must take place up to mid-September, six weeks before the estimated end of the growing period (end of October).
Harvesting - SilageThere is a trade-off between crop yield, forage quality (esp. digestibility) and persistence. In practice, the optimum time to cut lucerne for quantity, quality and persistence is when 5–10% of the plants are flowering (early flowering). Harvesting practice has a big effect on crop persistence because the crown of the plant is the source of regrowth. The crop should not be cut lower than 7 cm from the soil surface. A spring-sown crop will be ready for its first cut in late July of the first year. Most of the protein (70%) and minerals (90%) are in the leaf so the aim of the harvesting technique is to recover as much of the leaf material as possible. Roller-type mower conditioners cut and condition the lucerne by crimping or crushing the stem when harvesting. This enhances the rate of moisture loss from the stem without extensive damage to the leaf. Leaf shatter will occur if the cut lucerne dries out too much. Lucerne silage can be clamped or baled. [caption id="attachment_15724" align="aligncenter" width="768"] Lucerne crop[/caption]
Key practice points
- Weed control during crop establishment is important.
- Apply sufficient P and K for growth.
- When cutting, avoid damage to the crown (cut no lower than 7 cm).
- Avoid excessive drying after cutting to prevent leaf shatter and loss.
- Little or no N needed for growth.
Further informationSeveral suppliers in the UK market provide lucerne seed:
- Barenbrug: www.barenbrug.co.uk
- DLF Trifolium: www.dlf.co.uk
- Cotswold Seeds: www.cotswoldseeds.com
- Limagrain UK: www.lgseeds.co.uk
- Germinal GB: www.germinal.co.uk
Southern green shield bug in soybean
OutcomeThe southern green shield bug is a relatively new soybean pest in Europe. It is becoming more abundant and could become a serious pest. Monitoring should start in May or June and continue during July and August. If economic thresholds are exceeded, pesticide application may be required in order to protect soybean yield and quality.
BiologyAdults of the southern green shield bug are 12 to 15 mm long and 7 to 8 mm wide. The body resembles a shield. There are three distinct white dots and two smaller ones and all of them are in line on the scutellum. This species can be easily confused with the green shield bug, Palomena prasina, which is also green. The green shield bug does not have white dots on the scutellum, and the larvae (nymphs) are not as colourful as the immature stages of Nezara viridula. There are up to five generations per year. Adults shelter overwinter in houses and barns and other structures. This is a Mediterranean species which has expanded its habitat because of the recent mild winters. An average January temperature higher than 5°C is a strong factor in the spread of this insect. It has therefore increased significantly in regions where this threshold is exceeded. The timing of adult emergence and induction of diapause, size and fitness of adults and temperature, among other factors, are of greatest importance for successful overwintering. The southern green shield bug responds strongly to climate change by shifting its distribution to the north. After overwintering, adults mate and the females lay up to 300 eggs in groups of 30 to 130 on the back of leaves. After hatching, the nymphs remain in the group until second instar. The southern green shield bug feeds by piercing plant tissue with needle-like stylets. The feeding punctures are not immediately visible. Adults and nearly all nymphal stages (2nd to 5th nymphal stage) feed on plant tissues. Soft parts of the plant and the developing flowers or fruits are preferred. Yellow or dark spots and even necrosis follow as a result of feeding. Feeding on flower buds can result in loss of the flower. The largest threat to the seeds is damage in the early stages of formation. Feeding injuries on pods result in seed damage and distorted pods. Experience shows that the bugs invade soybean crops in larger numbers in central Europe only when pods are ripening. Therefore, damage is limited so far. In south-eastern Europe, the bugs appear earlier, at the end of flowering period. The timing of invasion will probably change as the pest becomes more abundant, which is one of the reasons why this species can be expected to become a more serious problem in soybean production in the coming years. [caption id="attachment_15494" align="aligncenter" width="1024"] Southern green shield bug (nymphal stage) in group damaging soybean pods.[/caption]
ControlBio-control of the southern green shield bug is a challenge since antagonist species have not yet sufficiently established themselves in response to the spread. Treatment with insecticide has so far been only rarely justified. There are no insecticides approved for this potential pest in most European countries. Spraying may be needed to protect yield if shield bug populations are high (the threshold is 8 to 10 specimens collected in 10 sweeps with a sweep net at the beginning of flowering). This pest can be chemically controlled using organophosphate or pyrethroid compounds depending on the registration in every country. The use of trap crops (forage pea, bean, brassicaceous crops) should be considered. The purpose of trap crops is to attract shield bugs to lay eggs on them. These are subsequently chemically treated before the bugs spread to adjacent soybean plants.
Key practice points
- Fields should be scouted regularly and systematically for the presence of pests. The green shield bug is easily observed.
- Control measures should only be taken where a pest population approaches a profit-threatening “economic” threshold. The costs of applying a pesticide to a field with low yield potential may not be justified.
- When chemical control is needed, apply the lowest effective amount of the respective pesticide using equipment that is properly calibrated.