INFLUENCE OF SHORT-TERM CROP ROTATIONS WITH DIFFERENT PROPORTIONS OF SUNFLOWER ON SOIL WATER REGIME

The article analyses the features of water consumption of sunflowers in short-term crop rotations. Presents the results of the 2020‒2021 research carried out in the experimental field of Kharkiv National Agrarian University named after V. V. Dokuchaev, located in the area of the Left Bank Forest-Steppe of Ukraine. The soil cover of the experimental field is represented by typical chernozem heavy loam on loess-like loam. Soil moisture was determined by gravimetric technique. Sunflower water consumption was calculated using the water balance method. The sunflower yield was recorded manually. The purpose of our research was to determine how short-term crop rotations with different sunflower saturation affect the formation of the soil water regime and the yield of the crop itself. The experimental design included five-field crop rotations with sunflower saturation of 0, 20, 40, and 60 %. The control in the experiment was a five-field crop rotation without sunflowers. It was determined that the yield of sunflower seeds depended on the variants and ranged from 3,21 to 3,57 t/ha. The increase in the share of sunflower in crop rotation was accompanied by a decrease in its yield, in particular, due to the deterioration of moisture supply. Soil moisture consumption was the highest in crop rotation with sunflower saturation of 60 % (2969 m3/ha). Against the background of reducing the share of sunflower to 40 and 20%, moisture consumption was 2713 and 2824 m3/ha. The water consumption coefficient was high due to an increase in the share of sunflowers in short-term crop rotations. It was determined that in crop rotation with sunflower saturation of 40 % the coefficient of water consumption was the lowest. At the same time, this variant has the highest yield of sunflower seeds (3,57 t/ha). Increasing the saturation of short-term crop rotations with sunflowers up to 60 % should occur under conditions of the high culture of agriculture. Therefore, ways of efficient use of soil moisture to increase the yield of sunflowers in short-term crop rotations are being developed.