Soybean yield depending on the variety and geometrical disposition of plants in the Right-bank Forest-steppe zone of Ukraine

Анотація

The level of soybean yield can vary depending on the sowing density, row spacing, and the environmental factors. Core goal of our experiment was to investigate effect of row spacing and sowing density on the yield of the different soybean varieties. The experiment was conducted during 2016-2017 in the Uman district of Cherkasy region, on the experimental demonstration field of Sedna-Agro Ltd, near the city of Uman. The objects of the experiment were soybean varieties Alligator, Senator and Mentor, which are absolutely appropriate to current climate zone. Output data, which was get by our experiment, was analyzed by using statistical analysis. The results of the study showed that there is a positive correlation coefficient between crop yield and density, and a negative correlation coefficient is established between the width of row spacing and the yield. It means that when we increasing the density, as well as decreasing the row spacing, we observe increasing of the yield level. Soybeans experiments involving factors such as sowing density and spacing were carried out in the past all around the world. And even today there is lot of experiments which are involve row spacing and density of the soybeans. Many scientists in the world agree that soybean seeding rate increases yields, but the
question of the most effective row spacing usage, and the individual reaction of the variety to the change of row spacing and seeding density, stays open even today. Generally accepted view is individual for each of the largest soybean producing countries, and scientists' conclusions, of the influence of optimal row on yield, in many cases, are controversial and still open for discussion and remains relevant for today. The level of soybean yield depends on many conditions. To obtain high and stable crops of soy, it is necessary to provide plants with the factors of life in an optimal ratio. However, some of adjustments are made by weather conditions, which are distinguished by variegated during the growing season. This is manifested in an increase in average daily temperature and uneven distribution of precipitation. That’s why today our farmers need to choose strategy to grow a particular variety for different sowing densities and widths of the row, in accordance with the possibilities of farming and agro-climatic conditions. The yield of soybeans depends on the reserves of productive moisture in the soil, which accumulated during the autumn-spring period, the genetic potential of a particular variety, the correct control of weeds, pests and diseases, as well as many other factors. The optimum crop density is a prerequisite for obtaining high yields. If the sowing density is below the optimum level, no measure will help to obtain a high grain yield. In addition, presowing treatment with seed dressing, helps to avoid premature death of the plant through illness, and this increases the similarity. In the study of yield dependence on soybean density, we obtained a rather low correlation coefficient of 0.21, which is due to the individual reaction of varieties to slightly different weather conditions during the 2016-2017 years of experiment. A negative correlation coefficient between yield and row width is established -0.169, which means that when we increasing the row spacing of soybeans, we observe some decreasing of the yield level. In our experiment, during each year, we had 27 regions which are separated by three different groups of row widths, and then each of it is separated by three
different sowing density, and in each density we had each of our three varieties: Alligator, Senator and Mentor. We had three different row spacing types 12.5, 25, 45 (centimeter), and three different sowing density 500,600,700 (thousands of seed kernels per hectare). The total area of the experimental site was 300 square meters, accounting – 250 square meters. Placing sites is a randomized four-time repetition. As result of our experiment, we created a model of complex regression which is explains row width and density influence to the yield level, that can be represented as an equation: Y = 0.00705X+0,002133X12 – 0,15915X1 +33,779, where X is density (thousands of seeds) and X1 is row width (in centimeters). It is worth saying that such experiments are carried out in the world and in Ukraine, and scientists come to the conclusion that with increasing sowing rates per hectare, yield of soy increases. According to the research results, the optimum soybean density is 600 thousand pcs. per hectare. This density yields the highest and economically justified yield of soybeans, which is from 2.83 to 4.11 tons per hectare, depending on the variety of the given crop.