Productivity of soybean varieties of different maturity groups depending on plant density under drip irrigation in the South of Ukraine

Abstract

Soybeans are a leading leguminous crop for universal use, therefore, measures aimed at increasing their productivity, including the reasonable selection of varietal resources and optimisation of planting density, will make a significant contribution to the creation of sustainable food production systems. The research aims to determine the effect of plant density on the productivity of soybean varieties of different maturity groups. Field laboratory and statistical (correlation and regression analysis) methods were used in the study. The field experiments were conducted during 2018-2020 on dark chestnut soil of a private agricultural enterprise of the agricultural company “Syvash” in Novotroitsk district of Kherson region. Its maximum values for the cultivation of early ripening varieties were ensured by a plant density of 700 thousand/ha, medium early varieties – 500-700 thousand/ha, and medium ripening varieties – 500 thousand/ha. A strong and very strong correlation between yield and soybean yield index was established. Increasing the length of the growing season contributed to the growth of yields. In the group of early maturing soybean varieties, the Monarch variety was determined to be the most productive. There was no significant difference in the level of yield of varieties within other maturity groups. For each variety, the optimum planting density was determined, at which the maximum grain yield was formed. Longer vegetation contributed to a greater accumulation of protein and fat in the grain. In terms of protein content, the difference between varieties of the same maturity group did not exceed 0.2%, but varieties differed in terms of conditional protein yield per hectare of crops. There was no difference in the fat content of mid-season soybean varieties. Among the early-ripening varieties, the Monarch variety was distinguished by higher oil content, and among the mediumearly varieties – by Aratta. The maximum conditional fat yield per hectare of crops was also determined for these varieties. A very strong and strong correlation was found between soybean grain yield and protein and fat content, respectively. A very strong correlation was also found between the protein and fat content of the grain. To ensure sustainable production and efficient use of soybeans and soybean by-products, it is advisable to take the results of the study into account in production conditions