Effects of Different Irrigation Levels on Sugar Beet and Potential Use of Crop Water Stress Index in Irrigation Scheduling

With the increasing world population, global warming, and climate change, water scarcity significantly limits water use in crop production. Therefore, timely and accurate determination of water stress is very important for the correct and effective management of existing water resources and minimizing harmful effects on crop production. Two years of experiments were conducted in the water-limited region in T & uuml;rkiye to investigate the possible use of the Crop Water Stress Index (CWSI) as a remote sensing technology in sugar beet irrigation scheduling. Four different Irrigation levels (I-50: 50% deficit, I-75: 25% deficit, I-100: full irrigation, and I-125: 25% excess irrigation) were applied to sugar beet by drip irrigation system. The amount of applied irrigation water and crop evapotranspiration varied between 238-540 and 350-580 mm in 2021, and between 324-807 and 502-829 mm in 2022. In both years, the highest beed yields were obtained from I-100 treatments (83 and 130 t ha(-1)) and the lowest from I-50 treatments (66.7 and 67.4 t ha(-1)). Water Productivity (WP) and Irrigation Water Productivity (IWP) in both years decreased significantly by excessive irrigation. CWSI values ranged between 0.16-0.98 in 2021 and between 0.02-0.71 in 2022. CWSI was significantly related to yield and Leaf Area Index (LAI). According to the results, CWSI could be used successfully in sugar beet irrigation scheduling and yield estimation.