INCREASE IN LEAF SURFACE AND PHOTOSYNTHETIC ACTIVITY OF SOYBEAN PLANTS DEPENDS ON SOWING RATE AND ROW WIDTH

Abstract

An essential condition for obtaining high soybean yields is the presence of an optimal leaf surface area. An important condition for obtaining the optimal leaf area in plants is the formation of a certain density of plants per unit area. It is known that the optimal area of the leaf surface, for which a high yield of soybean seeds is formed, is considered to be an area within the range of 40–50 thousand m2/ha. The purpose of the research was the determined dependence of the formation of the leaf surface area and the photosynthetic activity of soybean plants under the influence of the sowing rate and the width of the rows. The research was conducted during 2021–2023 at the experimental field of the VSP "Zalischytskyi Vocational College named after E. Khraplyvyh NUBiP of Ukraine". The following methods were used in the research process: field, laboratory, mathematical and statistical using generally recognized methods and methodical recommendations. The experiment was conducted on dark gray podsolized soil. The experiment was based on a three-factor scheme, where Diadema Podillia and Mentor varieties were factor A, and row width was factor B (15 cm – control, 30 cm and 45 cm); factor C is the sowing rate (500 thousand/ha - control, 600 and 700 thousand pieces of similar seeds per 1 ha. The predecessor is winter wheat. The conducted studies showed that the maximum leaf surface area was the Mentor variety - it reached 37,7-44,7 thousand/m2/ha during the seeding period. In the variety Diadema Podillia, the area of the leaf surface grew more slowly and reached the maximum size – 36,3-43,0 thousand m2/ha during the seeding period. The largest assimilation surface of soybean plants was formed at seed sowing rates of 500-600 thousand/ha in the Mentor variety, and in the Diadema Podillia variety at seed sowing rates of 600-700 thousand/ha. and for row widths of 30 and 45 cm in both varieties. It was established that the photosynthetic potential of Diadema Podillia soybean during the period of germination - full maturity was within the range of 1,95-2,21 million m2 days/ha, in the Mentor variety – 2,16-2,56 million m2 days/ha.