A web-based decision support system for assessing water productivity of major crops in Iran under different climatic conditions

Abstract

Abstract Knowledge on Water productivity (WP) of strategic crops, nationwide, will result in optimizing the consumption of agricultural water, proper cropping pattern and more financial benefits. In this study, a national web-based simulation portal was developed to evaluate the maximum achievable WP on a national scale. The National Water Portal (NWP) was consisting of four national databases (climatic, soil, crop and spatial data), a lump water balance model and a graphical user interface (GUI) to support computing the irrigation water requirements and evaluate the WP indicators at farm to national scale on the network. WP indicators defined as yield per crop evapotranspiration (WPETc), yield per net irrigation requirement (WPNIR), and the financial benefit per consumed water (WPEco) was calculated for the dominant strategic crop consist of winter wheat, barley, rice, maize, sugar beet and sugarcane. Net irrigation requirement was estimated using a lamp water balance model based on the dual crop coefficient approach presented by FAO 56. The results indicated that winter wheat and barley with NIR of 258 to 4235 m3 ha− 1 has the highest WPEco among the studied crops and rice with NIR of 4495 to 8907 m3 ha− 1 stands in the next category. WPEco for maize and forage maize (3747 to 7083 m3 ha− 1) was higher than WPEco for sugarcane and sugar beet. Sugar cane with NIR of 18318 m3 ha− 1 had distinguishably lower WPEco value among the studied crops because of its long growing season. The results suggested sugar cane to be replaced by with sugar beet (NIR from 5100 to 11896 m3 ha− 1) with 4 times higher WPEco.