Influence of technological elements on the formation of photosynthetic potential of annual sweet clover plants in rainfed lands in southern Ukraine

Abstract

Purpose. To establish the influence of sowing time and seed sowing rates on the formation of photosynthetic productivity and seed yield of annual white sweet clover in rainfed conditions in the South of Ukraine. Methods. The studies were carried out during 2015–2017. On the experimental field of the Institute of Irrigated Agriculture of the NAAS located in the Kherson region in the south of Ukraine. The studies were carried out according to the methods of conducting field and laboratory studies and methodological recommendations and manuals. Results. In the rainfed conditions of the South of Ukraine, the net productivity of photosynthesis and the photosynthetic potential of melilot of the annual white variety Pivdenny were established, depending on the sowing time and seeding rates. On average for 2015–2017 research has established that from a biological point of view, the best sowing time for growing annual white sweet clover for seeds in rainfed conditions in the South of Ukraine is sowing in the first ten days of April at a seeding rate of 2,5 million pcs/ha. The best sowing period for growing white annual clover for seeds in rainy conditions in the South of Ukraine is sowing in the first decade of April with a sowing rate of 2,5 million units/ha. The maximum index of photosynthetic potential in the crops of the white annual sweet cultivar Pivdenny is taken out during the first decade of April – 1,80 million m2 d./ha in the mid-phase period of blooming – the growing season. So, on average for 2015–2017 of research, the maximum yield indicator – 876,6 kg/ha was formed during sowing in the first decade of April. According to favorable agroclimatic indicators in 2015, the yield of white sweet clover seeds reached a maximum value of 1 130 kg/ha during sowing in the first decade of April at a seeding rate of 2,5 million pcs/ha.