ВЛИЯНИЕ РЕЖИМОВ ОРОШЕНИЯ НА ВОДОПОТРЕБЛЕНИЕ, РАЗВИТИЕ И УРОЖАЙНОСТЬ СОИ

Abstract

Purpose: to study the impact of irrigation regimes on soybean water consumption, development and yield. Materials and methods. The studies were carried out on meadow-chernozem soils of Oktyabrsky district Rostov region in 2021–2022. Experience consists of five options: 1) control 1 m; 2) 1.2 m; 3) 0.8 m; 4) 0.6 m; 5) without irrigation. Field experiments and statistical processing of data were carried out in accordance with generally accepted methods, taking into account zonal features. Results. The influence of irrigation regimes on soybean plants height, the yields formation and the structure of net consumptive water use was determined. It has been determined that in the slightly dry year 2021, the irrigation regime consisted of four irrigations, and in the very dry year 2022 there were six irrigations. Watering rate on the control was 450 cubic meters per hectare. Irrigation rate in 2021 changed from 1080 to 2160 cubic meters per hectare, and in 2022 – from 1620 to 3240 cubic meters per hectare, depending on the irrigation regime and the moisture supply of the growing season. The most intensive growth of soybean plants was observed after the flowering phase, and the height reached its maximum values in the bean filling phase. Irrigation regimes with increased and reduced irrigation rates led to a decrease in soybean yield by 7–40 %. On average, the maximum yield was obtained in the control variant (1 m) – 4.18 t/ha. In the non-irrigated variant, the yield was 1.97 t/ha, which is 53 % lower than the control one. The net consumptive water use during the growing season varied from 3132 to 5472 cubic meters per hectare, depending on the conditions of moisture supply. In the structure of net consumptive water use irrigation water accounted for 31 to 49 %, and precipitation – from 48 to 84 %. Conclusions. On average for 2 years, the highest soybean yield was obtained in the control variant (1 m) – 4.18 t/ha. A 20 % reduction in irrigation rate resulted in a 7 % yield reduction and irrigation water savings of 450 cubic meters per hectare. The net consumptive water use of crops was from 3132 to 5472 cubic meters per hectare, depending on the options.