Grain legumes (soybean, peas, chickpea) are valuable preceding crops in the rotation and important export crops. Their yield depends on the productivity of nitrogen fixation, which can be influenced to a large extent with fertilizers.
A specific feature of grain legumes is their need for molybdenum, a component of the enzymes nitrate and nitrite reductase, under whose action oxidized forms of nitrogen NO2, NO3 must be transformed into reduced NH3 and NH2. Molybdenum deficiency most often appears on light soils and on acidified varieties of gray forest soils and chernozems.
In soybean the process of nitrogen fixation, in symbiosis with nodule bacteria, begins at the two true leaf stage, so sufficient molybdenum supply to plants in this period is very important. For this purpose ECOORGANIC advises foliar feeding with the microfertilizer ECOLINE Molybdenum (Complex) 0.5–1.0 l/ha (from the 2-true-leaf stage to budding). This year's May weather is not very favorable for grain legumes, so it is worth adding ECOLINE Phosphite (K-Amino) 1.0 l/ha to the tank mix to reduce the negative effect of stress factors.
Imbalance in mineral nutrition conditions reduces yield and worsens its quality. On carbonate soils iron and zinc deficiency is possible, and on acidic soils calcium deficiency. Symptoms of iron and zinc shortage show visually on soybean leaves as interveinal chlorosis, the result of a complex disturbance of plant development on soils with an alkaline reaction and/or a high concentration of salts in the soil solution. Chlorosis can intensify on over-compacted, waterlogged soil and during cold spells. To eliminate signs of iron and zinc deficiency we suggest foliar feeding with the fertilizers ECOLINE Iron (Chelate), ECOLINE Zinc (Chelate) at the start of pod formation at doses of 0.5–1.0 l/ha.
With calcium deficiency plants lag in growth, and fewer colonies of nitrogen-fixing bacteria (nodules) form on the roots. Moreover, these nodules are smaller, lighter in colour in cross-section and less active. On very acidic soils nodules may not form at all. To eliminate calcium deficiency we recommend using the special fertilizer ECOLINE Calcium-Boron (Chelates) 1.5–2.0 l/ha at budding.
Pod fill, and therefore the soybean grain yield, depends on how fully the flowers are pollinated, so at the start of pod formation it is desirable to feed plants with the special fertilizers GROS Quicelium (1.0–1.5 l/ha) and ECOLINE Boron (Organic) 0.5–1.0 l/ha.
During grain formation in the pods, plants need increased nitrogen nutrition and a balanced supply of other macro- and microelements. At this time we recommend foliar feeding with a 5–6% urea solution combined with ECOLINE Legume (Chelates) at 1.5–2.0 l/ha. On areas damaged by spider mites, it is advisable to apply ECOLINE Magnesium (Chelates) 1.5–2.0 l/ha together with the acaricide to stimulate chlorophyll recovery and intensify photosynthesis.