The objective of the research is to determine the variants of effective water use for soybean growing at clay loam ordinary chernozems. The experiment was carried out in the Rostov region in 2011-2013. The experiment included three variants of soil water regime: intense (irrigation while soil moisture content decreases up to 75–80 % FC in soil layer of 0.6 m), water-saving (irrigation at the period “initial flowering – fructification”), and without irrigation. The generally accepted methods were used in the research. It was found that the crop yield upon intensive irrigation was 2.33 t/ha, what is 1.7 times higher than for rainfed conditions. The yield upon water-saving irrigation was 1.86 t/ha, or 1.3 times higher than for rainfed conditions. In water-saving variant, soybean yield decreased by 20.2 % comparing with intense irrigation, while irrigation water saving was 1570 m³/ha. The water-saving variant provided the most efficient water use. This was confirmed by the least coefficient of water consumption, 1463 m³/t. This indicator was by 13.7 % lower than upon intensive irrigation. The lowest consumption of irrigation water per unit of yield increase (1152 m³/t) was found for water-saving irrigation regime. The highest yield of additional production per 100 m³ of irrigation water was also obtained in the same variant, 0.09 ton. For soybean growing at irrigated lands with water shortage water-saving regime is recommended, which provides one irrigation in the period from initial flowering till fructification by the norm of 530 m³/ha.
Keywords: soybean, water saving, irrigation regime, irrigation requirement, yield, total water consumption.
