H. A. Irik - Department of Biosystems Engineering, Faculty of Agriculture, University of Erciyes, Kayseri, Türkiye.
E. Kaymaz - Department of Research and Development, Kayseri Sugar Beet Factory, Kayseri, Türkiye.
H. Neslihan Samutoglu - Department of Research and Development, Kayseri Sugar Beet Factory, Kayseri, Türkiye.
O. Fikret GURKAN - Department of Research and Development, Kayseri Sugar Beet Factory, Kayseri, Türkiye
A. Unlukara - Department of Biosystems Engineering, Faculty of Agriculture, University of Erciyes, Kayseri, Türkiye.

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 Türkiye 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 (I۵۰: ۵۰% deficit, I۷۵: ۲۵% deficit, I۱۰۰: full irrigation, and I۱۲۵: ۲۵% excess irrigation) were applied to sugar beet by drip irrigation system. The amount of applied irrigation water and crop evapotranspiration varied between ۲۳۸-۵۴۰ and ۳۵۰-۵۸۰ mm in ۲۰۲۱, and between ۳۲۴-۸۰۷ and ۵۰۲-۸۲۹ mm in ۲۰۲۲. In both years, the highest beed yields were obtained from I۱۰۰ treatments (۸۳ and ۱۳۰ t ha-۱) and the lowest from I۵۰ treatments (۶۶.۷ and ۶۷.۴ t ha-۱). Water Productivity (WP) and Irrigation Water Productivity (IWP) in both years decreased significantly by excessive irrigation. CWSI values ranged between ۰.۱۶-۰.۹۸ in ۲۰۲۱ and between ۰.۰۲-۰.۷۱ in ۲۰۲۲. 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.

Deficit irrigation, Irrigation water productivity, Leaf area index, CWSI.