Grain legumes soybean, peas and chickpea are valuable preceding crops in the rotation; their yield is determined by the productivity of the nitrogen fixation process, which can be regulated to a large extent. The nitrogen fixation process in symbiosis with nodule bacteria begins at the stage of two true leaves. As a result of the breaking of the triple bond in the nitrogen molecule N2, oxidized forms of nitrogen NO2 NO3 begin to accumulate in the root system of legumes; for the plant to assimilate them, the oxidized forms of nitrogen must be transformed under the action of the enzymes nitrate and nitrite reductases into reduced forms NH3 and NH2 .
Feeding soybean plants with molybdenum
Molybdenum is a component of these enzymes, so sufficient molybdenum supply to soybean plants during the nitrogen fixation process is an important condition. Molybdenum deficiency most often appears on light soils and on acidified varieties of gray forest soils and chernozems. To solve this problem ECOORGANIC suggests using the microfertilizer ECOLINE Molybdenum (Complex) for foliar feeding of legumes from the 2-true-leaf stage to budding at 0.5–1.0 l/ha. Since the seed of these crops is not always treated with microfertilizers for fear of reducing the effectiveness of the inoculant, it is advisable at this time to add to the tank mix the special fertilizer GROS Rootgrowth at 1.0–1.5 l/ha to strengthen the growth and functioning of the root system.
At this time it is important to assess the level of phosphorus nutrition of plants and, if its deficiency appears or as a preventive measure, to carry out foliar feeding of plants with phosphorus in the form of phosphite, which the plant can quickly absorb and which shows a fungicidal action. The recommended dose of ECOLINE Phosphite (K) for grain legumes is 1.0–1.5 l/ha.
The crop's range has expanded over the last two decades, and soil conditions are not always optimal, so deficiency of other microelements may appear on crops, in particular iron on carbonate soils or calcium on acidic ones. Symptoms of iron shortage show on soybean leaves as interveinal chlorosis as a 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.
Imbalance in mineral nutrition conditions
Imbalance in mineral nutrition conditions reduces yield and its quality. To eliminate possible deficiency of this microelement we suggest using our product ECOLINE Iron (Chelate), which is used for foliar feeding at the start of pod formation at 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; they are smaller, less active and lighter in colour in cross-section. On very acidic soils nodules may not form at all. To overcome mild calcium deficiency we recommend foliar feeding at budding with the special fertilizer Ecoline Calcium-Boron Chelates at 1.5–2.0 l/ha.
Pod fill, and therefore soybean grain yield, depends on how fully the flowers are pollinated, so at the start of budding it is desirable to feed plants with the special fertilizer GROS Quicelium at 1.0–1.5 l/ha, and for boron we suggest using, depending on plant condition and weather, ECOLINE Boron (Premium) or ECOLINE Boron (Organic) at 0.5–1.0 l/ha. In the 2017 field trials, thanks to feeding with GROS Quicelium we obtained on average 31.5 pods per plant against 21.7 pods in the control, which gave a yield gain of 7.2 c/ha compared with the control, and the financial result was also significant, USD 170.7/ha.
During grain formation in the pods, plants need increased nitrogen nutrition balanced with other macro- and microelements. 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 appropriate to apply ECOLINE Magnesium (Chelates) at 1.5–2.0 l/ha together with the acaricide to stimulate chlorophyll recovery and intensify photosynthesis.