A Simple and Farmer-Friendly Decision Support System for Enhancing Water Use Efficiency in Agriculture:Tool Development, Testing and Validation

In the semi-arid tropics (SAT) farmers practice calendar- based irrigation scheduling, which generally results in over irrigation and poor water use efficiency. The lack of a simple decision tool to decide timing and quantity of water to be applied is a bottleneck. An Excel-based decision support system termed Water Impact Calculator (WIC) is developed using data collected at the ICRISAT, which were validated at three pilot sites on farmers' fields in Rajasthan, Gujarat and Telangana. Field studies were conducted under two land-form treatments (broad bed and furrow (BBF) and flat fields); and irrigation water was applied following two different methods (drip and flood). The data collected at micro-watershed at the ICRISAT and three other sites showed that WIC could be used under wide range of soil and rainfall conditions. WIC simulated soil moisture was comparable with the observed moisture data, which forms the basis of irrigation scheduling. The WIC-based water balance at these experimental sites showed that number and amount of irrigation could be reduced by 30-40% using WIC-based irrigation scheduling without compromising the crop yield. The WIC could be a potential tool for water resources planning and efficient management at the field and watershed scale in the SAT.