Soybean

Small grains such as wheat, barley, rye, and triticale are excellent pre-crops for soybeans, followed by corn and potatoes, which allow sufficient time for soil preparation before sowing soybeans. Sunflowers and canola, which share common diseases with soybeans, should be avoided. Monoculture of soybeans is not recommended due to the risk of plant diseases and challenges in tillage and weed management.
       
During the fall, it's essential to plow the meadows to incorporate harvest residues, and plowing also helps in storing precipitation throughout the winter. At winter's end, it's important to close the furrows to retain moisture. Subsequently, employ a seed drill to break up the soil and ready the seeding layer. For uniform and high-quality germination, meticulous preparation of the sowing layer is crucial; the base should be compact, while the top layer needs to be friable. Seeds sown in such well-prepared soil meet all conditions for swift and consistent emergence. Ignoring these practices can lead to a significant reduction in crop yield.

For a yield of 1 ton of grain and the associated vegetative mass including roots, a soybean plant requires: 50 kg/ha of N, 40 kg/ha of P₂O₅, 50 kg/ha of K₂O, and 10 kg/ha of MgO. Soil analysis is essential, and based on the results, fertilizers should be supplemented accordingly. Phosphorus and potassium should be applied in the fall during soil preparation. Nitrogen can be introduced at sowing time in a form that dissolves easily and quickly assimilates into the soil solution, allowing the plant to absorb it through its root system. For a rapid initial growth and sprouting, the plant needs nitrogen, which can be applied before sowing in small amounts (30-50 kg of pure nitrogen per hectare). Nitrogen fixation from the atmosphere by nodule bacteria starts approximately a month after germination (2-3 trifoliate leaves), and during this period, the plant requires nitrogen. As a legume, soy can fix nitrogen from the air, fulfilling up to 40% of its nitrogen requirement. Soybeans should be planted 3-4 years after manure application in the fields. Foliar feeding with pine has proven effective in pod setting and grain development.

Soy requires substantial water for its growth. During its vegetative cycle, soybeans necessitate approximately 400-450 mm of water, considering the air's relative humidity. Adequate agricultural practices and preparation before sowing help retain moisture in the seedbed, crucial for germination, emergence, and optimal crop establishment. Water remains vital throughout the growth cycle, particularly during key phenophase such as flowering and pod filling, where air humidity also plays a significant role in successful flower fertilization and pod development.

In soybean cultivation, the most crucial practice is weed control, as weeds compete for nutrients, water, sunlight, and space. Weeds not only diminish yields but also complicate harvesting and degrade grain quality. Weed control can be achieved through two methods: mechanical control using spartan and chemical treatments.

Spartan mechanical control is feasible when the rows are spaced either 50cm or 70cm apart. The initial spartan should be conducted when the soybeans reach the third trellis stage, and the subsequent one while the field is still accessible without harming the crops. It's essential to allow a one to two-week interval after applying herbicides before proceeding with cultivation.

We control weeds in soybeans through two to three applications. The initial treatment, known as PRE EM, is applied after planting but before the soybeans emerge. This herbicide is distributed on the soil, and it requires a bit of rain to integrate into the soil solution. Once in the soil solution, weeds absorb the herbicide through their roots. Since soybeans are not tolerant to these herbicides, application must occur before they germinate and sprout.

The second application is performed from when the first leaves appear until just before flowering begins, often in a split application 10-15 days apart. This treatment targets broadleaf weeds.

Treatments for narrow-leaved weeds should be done separately from those for broad-leaved weeds, and these herbicides should not be mixed.

It's also crucial to consider the agents used in the previous crop, as soybeans can be sensitive to residues from some previously applied herbicides.

In periods of intense heat, it's advisable to conduct treatments in the evening to avoid the peak temperatures.

During the summer, spider mites (Tetranychus urticae) may emerge, typically starting at the edges of roads and spreading towards the field's interior. To prevent heavy infestation and rapid spread, one should use an acaricide. Often, it suffices to spray only the affected areas, and there is no need to treat the entire surface. In some years, the Painted Lady butterfly (Vanessa cardui) may also surface, feeding on soybean flower pollen before laying eggs on the plants. The hatched caterpillars then consume the soybean pods and leaves. Should there be a significant presence of these butterflies, it is necessary to apply insecticides targeting the eggs and larvae.