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Maturing white lupin plant.   Lupinus albus cultivation Lupin 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 soil Spring-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.   Young white lupin.   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. Water Under 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 irrigation We 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.   Lupinus albus grains.   Crop responses We 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 information Gresta, 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).   Soil sensors Drill and Drop (a,b) Enviroscan (c,d).

Rust.   Outcome A 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 distribution Faba 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.   Symptoms Rust Towards 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 spot The 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.   Risk factors Rust The 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 spot The 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.   Chocolate spot and rust.   Economic impact Rare 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.   Prevention Several 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 treatment Tebuconazole 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.   A crop infected with uncontrolled chocolate spot and rust.   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.