SOIL WATER REGIME AND POTATO YIELD UNDER DIFFERENT IRRIGATION METHODS IN THE POLISSYA REGION OF UKRAINE

In this scientific study, the parameters of irrigation regimes, evapotranspiration (ETc) values, and potato yields were experimentally determined depending on irrigation methods and water supply regimes. To conduct the study, a short-term (2023-2025) field experiment, analytical and statistical methods of experimental data processing were used. It has been proven that the method of laying irrigation pipelines for drip irrigation systems, the method of irrigation, and the water supply regime have a significant impact on evapotranspiration, soil water regime, and potato tuber yield in the Polissya region of Ukraine. Thus, the amount of evapotranspiration of plantings varied depending on the water regime: 2,20–2,51thousand m³/ha in non-irrigated conditions; 4,47–5,31 thousand m³/ha in the case of underground placement of irrigation pipelines (at a depth of 0,30 m), 4,72–5,61 thousand m³/ha for drip irrigation with periodic water supply, and 4,30–5,17 thousand m³/ha for drip irrigation with pulsed water supply. Under sprinkler irrigation, evapotranspiration was highest, ranging from 5,80 to 6,24 thousand m³/ha over the years of the study. It is natural that without irrigation, the lowest yield of marketable tubers was obtained – 43,4 t/ha, and the factor of "irrigation" in combination with fertigation increased this indicator by an average of 1,5 times – to 65,15 t/ha. The increase in tuber yield with drip irrigation with periodic and pulsed water supply was statistically significant: up to 66,4 t/ha and 70,4 t/ha, respectively. Under conditions of sprinkler and subsurface drip irrigation, 60,8 t/ha and 62,7 t/ha were obtained, respectively. The minimum specific irrigation water consumption was obtained with drip irrigation with a pulsed water supply mode – 67,6 m³/t, respectively. The highest water consumption coefficient was for sprinkler irrigation – 100,4 m³/t. Thus, when growing potatoes in the Polissya region of Ukraine, it is more expedient to use drip irrigation, preferably with a pulsed water supply mode, and in conditions of acute water shortage for irrigation, drip irrigation with underground installation of irrigation pipelines.