IMPACT OF TEMPERATURE ANOMALIES ON THE IRRIGATION NEED OF AGRICULTURAL CROPS

Abstract

The article highlights the issue of forecasting potential evapotranspiration (ET₀) and temperature changes in the summer period (June–August) 2023–2030, taking into account water consumption by agricultural crops and the SPEI drought index. Increasing air temperature, especially in the summer, significantly affects the water balance of agroecosystems, causing increased evaporation from the soil surface and plant transpiration. It is found that an increase in average summer temperature by 0.3–0.5 °C each year will lead to an increase in ET0 from 18.74 mm in 2026 to 23.41 mm in 2030, reflecting increased evaporation and soil moisture deficit. Studies have shown that crop water consumption coefficients (Kc) will increase: corn from 0.81 to 0.85, soybeans from 0.71 to 0.75, vegetables from 1.01 to 1.05, which, together with the increase in ET₀, will increase the need for irrigation: corn – 15.18–19.9 mm, soybeans – 13.31–17.56 mm, vegetables – 18.93–24.58 mm. Studies have also found that decreasing SPEI values – from –0.5 to –2.5 will increase water stress and increase potential evapotranspiration by 5–25 %, indicating an increased risk of summer droughts in the region. The research results provide grounds to recommend the use of adaptive and water-saving irrigation technologies, the integration of agrometeorological forecasting with water resources management, and the priority provision of vegetable crops during critical phases of development. It has been established that irrigation becomes a necessary agrotechnical measure as early as 2027–2028, and by 2029–2030, climatically intense summer conditions close to southern steppe conditions will form. Further research is promising to assess the effectiveness of various irrigation systems, the introduction of drip and micro-irrigation, development of climate-oriented water use models and integration of agrometeorological forecasting with the management of land reclamation systems to increase the resilience of agroecosystems of the Poltava region to increasing temperature anomalies and droughts.