Determining virtual water, physical and economic indices to optimize agricultural water consumption in three different climates

The use of water productivity indicators for management of water resources is considered in different regions of the world. This research was conducted with the aim of using virtual water and physical and economic productivity indices of water for major agricultural crops to optimize water consumption. The research was conducted for 26 farms in Kurdistan, Iran with three different climates. Reference crop evapotranspiration and effective precipitation were calculated using CROPWAT software. The amount of water consumption was calculated by separating green and blue water and compared with field measurements in the 2017 crop year. To calculate physical productivity and economic productivity, the crop water productivity (CWP) index and the benefit per drop (BPD) and net benefit per drop (NBPD) indices, respectively, were used. The results showed that sugarbeet and barley have the highest and lowest CWP with 4.55 and 0.43 kg/m³, respectively. The measured water consumption in most farms is larger than the calculated values. According to the CWP index, the priority of crop cultivation is sugarbeet, potato, cucumber, apple, alfalfa, wheat and barley. However, BPD and NBPD indicators showed that the priority of cultivation is apple, cucumber, potato, sugarbeet, alfalfa and wheat respectively. The results of the NBPD index showed that apple and barley have the highest and lowest water economic productivity with 54,000 and 2000 IRR/m³, respectively. The findings, elucidating the significance of employing water economic indicators as opposed to water consumption metrics, can serve as a valuable reference for agricultural practices in analogous climatic regions globally.