Estimation of Cropwater Use Efficiency in Furrow Irrigation of Bushbean Crop Using Cropwat 8.0 Model

Efficient use of water in agriculture is becoming increasingly critical, particularly in semi-arid regions like Anantapuramu district. Anantapuramu district (14.6819° N latitude and 77.6006° E longitude), which covers a geographical area of 1.913 million hectares. The district has a semi-arid climate, with hot and dry conditions for most of the year. This study focuses on estimating crop water use efficiency (WUE) of bush bean under different irrigation methods using the CROPWAT 8.0 model in the semi-arid conditions of Anantapuramu district. The weather data used for CROPWAT 8.0 model was collected for Madakasira mandal of Anantapuramu district for the years 2011 to 2020. The crop water requirement for bush bean was determined. The results clearly shows the relationship between water use, crop yield, and water use efficiency (WUE) under different irrigation methods. Flood irrigation used the highest amount of water (328.9 mm) but resulted in a relatively low yield (1000 kg/ha) and the lowest water use efficiency (3.04 kg/ha-mm), indicating poor water management and significant losses. Full (100%) irrigation improved yield significantly (1281.25 kg/ha) with slightly reduced water use, resulting in higher efficiency (4.27 kg/ha-mm), making it suitable where water availability is not a constraint. Deficit irrigation reduced water use (231.5 mm) while maintaining a relatively high yield (1187.5 kg/ha), leading to improved efficiency (5.13 kg/ha-mm), thus providing a balance between water saving and productivity. Partial Root Zone Drying (PRD) irrigation used the least water (141.2 mm) while maintaining yield (1000 kg/ha) and achieving the highest water use efficiency (7.08 kg/ha-mm), making it the most efficient irrigation method. There is a modify backward relationship between facility use and facility use efficiency. PRD was the most efficient method, followed by deficit irrigation, while flood irrigation was the least efficient and unsuitable under water-scarce conditions. For sustainable nutrient management, PRD and deficit irrigation methods are advisable, especially in regions grappling irrigate limitations.