Soybeans exhibit significant sensitivity to day length and temperature, making sowing dates a decisive factor in yield formation. The minimum soil temperature for germination to begin is +8...+10 °C, with +12...+14 °C considered optimal. Sowing in colder soil leads to delayed emergence and reduces the crop's competitive ability against weeds.
The duration of the soybean growing season is plastic and depends on the sowing date, temperature, and moisture conditions. Early sowing at low temperatures increases the risk of thin stands, while excessively late sowing dates may cause the pod formation phase to coincide with the period of autumn cooling. For northern ecotype varieties, earlier dates are acceptable; however, for any variety, it is critical to ensure conditions for the full development of vegetative mass prior to flowering.
An incorrectly chosen sowing date negatively affects the yield structure; in particular, it can lead to low positioning of the bottom pods, which increases harvest losses. If shifting to later sowing dates is necessary, an adjustment of the seeding rate upwards is often required to maintain optimal stand density.
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Sowing date.