Utilizing crop water stress index for efficient irrigation scheduling of wheat (Triticum Aestivum L.)

The study aimed to assess the viability of utilizing canopy temperature-based crop water stress index (CWSI) for scheduling of irrigation in wheat crop (Triticum Aestivum L.). Field experiments were carried out for 2021-2022 and 2022-2023 cropping periods at irrigation laboratory of Civil Engineering Department at Indian Institute of Technology Roorkee, Roorkee, India. The experimental field was divided into six plots, each subjected to different irrigation treatments based on the depletion of total available soil water (ASW) within the crop's root zone. These irrigation treatments maintained varying levels of water depletion in the soil (WDS) of TASW, encompassing 10%, 25%, 35% and 50%, as well as fully irrigated (non-stressed) and extremely dry (fully stressed) conditions. To establish a baseline, multiple regression analysis between meteorological variable and crop parameters were conducted.  The CWSI was subsequently calculated for various levels of WDS of ASW using an empirical method. It was found that the irrigation treatment corresponding to 50% WDS, with a mean CWSI of 0.36, resulted in optimal yield and maximum water use efficiency. The findings of the study suggest that the established CWSI value can effectively identify stress levels and serve as a valuable tool for scheduling irrigation in wheat crop.