The dissertation is aimed at the optimization of agrotechnical measures for the cultivation of soybean varieties in the conditions of the Right Bank Forest Steppe of Ukraine, which allows creating conditions for the good realization of the biological potential of the culture, its yield and the economic efficiency of cultivation.
In the interphase period, the beginning of the formation of beans - maturation, all soybean varieties studied by us showed a clear tendency to lengthen the duration of the growing season as the density of crops
increased from 450 to 750 thousand units/ha.
With a moisture deficit during the germination of soybeans, interactions between the density of crops and the width of the row spacing on the field germination of soybean seeds were observed. At the same time, higher sowing rates on narrow-row spacings reduced the similarity less than on wide-row spacings, where a local moisture deficit was observed due to the close location of seeds.
Before harvesting, soybean crops were in satisfactory condition and had sufficient density.
Thickening of crops contributed to an increase in the number of leaves on soybean plants, as a result of increased competition for nutrients, and especially the availability of solar energy.
It was established that the factors of the experiment influenced the number of colonies of active nodule bacteria on the soybean root system.
At the time of flowering, according to the thickening of crops, and especially on variants of wide-row crops, where the same amount of soybean seeds was located in wider interrows, we determined patterns of some increase in the height of the plants.
And in the later phases of growth and development (seeding), all varieties of soybeans, without exception, as the feeding area of one plant decreased, tried to find themselves in better conditions for assimilating solar energy and increased the height of the plants as a way to better arrange the leaf surface and optimize the arrival of larger amounts of light.
Some changes in the height of attachment of the lower bean on soybean plants of different varieties were also observed, however, taking into account the regularity of the increase of the height of the attachment of the lower bean as the total height of the plants increases, we believe that there are no separate trends to the influence of the investigated agrotechnical factors. That is, the height of the attachment of the lower bean depends on the overall height of the plants, and the taller the crops we have, the higher the flowers are located on the stem, and therefore both height indicators change synchronously.
The indicator of the number of beans per plant depends both on the biological indicators of the studied varieties and on the characteristics of the growing conditions, and in particular, on the formation of a good level of plant nutrition due to the optimal area and their location in space.
The rate of sowing seeds had a significant effect on the number of seeds on soybean plants, especially in the context of the formation of prerequisites for its reduction with an increase in the number of plants per unit area. This was especially clearly observed in the sub-optimal parameters of the plant's feeding area, for the use of 38+38+38 cm row spacing and 750,000 seeds/ha for growing soybeans.
The most significant changes in the mass of seeds per plant were observed in the case of an increase in the density of crops, to which soybean plants responded by reducing the mass of seeds per plant, however, in total, this could not significantly affect the overall level of productivity at the expense of exactly the same density of crops.
The best yield in the Sirelia variety, and the maximum according to the experiment, was obtained with the width of the rows 19+38+19 cm and the sowing rate of 750 thousand pieces/ha - 2.92 t/ha.
Increasing the width of the rows and growing different varieties of soybeans with a seeding density of 450,000 seeds per hectare contributed to better protein content in the seeds.
According to the energy accumulated in the biomass the maximum accumulation was observed in the Sirelia variety when growing plants with a row spacing of 19+38+19 and a seeding rate of 600,000 units/ha, 77,585 MJ/ha of energy was obtained, while the best indicator was recorded according to the experiment at a seeding density of 750,000. units/ha – 78396 MJ/ha.
According to the coefficient of energy efficiency, according to the experiment, the best level of energy efficiency was obtained in the Sirelia soybean variety for its cultivation with a row width of 19+38+19 and a seeding rate of 750,000 units/ha - 3.51.
