WATER REGIME AND EFFICIENCY OF GROWING SUNFLOWER HYBRIDS DEPENDING ON THE ELEMENTS OF DRIP IRRIGATION TECHNOLOGY

The article presents the results of experimental research on the influence of micro-irrigation system designs on the water regime, productivity, and efficiency of sunflower cultivation. Based on this, the main economic parameters of agrotechnologies of sunflower cultivation were calculated. Short-term field research was carried out in the period 2020-2022 on the lands of the Brylivske experimental field of the Institute of Water Problems and Reclamation of the National Academy of Agrarian Sciences (Kherson Region, Dry Steppe subzone). Analytical and statistical methods were used to process experimental data. The scheme of field experiments provided different options for laying irrigation pipelines of micro-irrigation systems (in the horizontal and vertical planes) and the implementation of a pulsed water supply mode (standard). The control was the variant without irrigation. According to the results of experimental studies, it was proved that the method of laying irrigation pipelines of micro-irrigation systems significantly affects the parameters of the formation of the soil water regime and the yield of sunflower hybrids in the conditions of the Dry Steppe. It has been established that the introduction of subsurface drip irrigation is more appropriate than the cultivation of sunflower hybrids, which is explained by the drought resistance of this crop. When growing sunflowers, the variant with the subsurface laying of drip irrigation pipelines provided almost identical yield parameters at lower plant water consumption coefficients. The minimum water consumption coefficient (1077,8 m3/t) was obtained by implementing the pulse water supply mode. The highest economic parameters of agricultural technology for growing sunflower hybrids were obtained with the subsurface drip irrigation: conditionally net profit (17,11-18,17 thousand UAH/ha), lower cost (11,03-10,90 thousand UAH/ton), and also a higher level of production profitability (31,10-32,62%) (laying irrigation pipelines every 1,0 m, regardless of the sunflower hybrid). Due to the higher grain yield and specific savings of irrigation water in the pulse mode of water supply, the highest economic parameters were achieved: gross income amounted to 80,51 thousand UAH/ha, conditionally net profit – 21,24 thousand UAH/ha, cost of 1 ton of grain - UAH 10,6 thousand and the level of profitability of production – 35,8%.