Evaluation of different irrigation methods using water, energy, food and carbon nexus approach

The aim of this study was to investigate the effect of using each of the surface, sprinkler and drip irrigation methods on the condition of Zayandehrud basin. For this purpose, water, energy, food and carbon nexus approach was used for a comprehensive study. In the nexus approach, considering their interactions, efforts are made to increase productivity and ensure the security of the region. In this study, this approach has appeared in the form of a newly developed index called water, energy, food and greenhouse gases nexus (WEFGN) and considering ten indicators including inputs of crop production, energy consumption for irrigation, food self-sufficiency, economic efficiency and carbon emissions were studied for irrigation methods that could provide a comprehensive view of managers and decision makers. The results of the study of irrigation methods in 2020 showed that by changing the current irrigation method to drip and sprinkler irrigation due to reduced water consumption (17 and 4.84 percent (483.7 and 138.5 million cubic meters per year, respectively)) the condition of the basin improves, but in the sprinkler method more energy is needed for irrigation (280.5 percent (112415.8 thousand kcal per year)) and the carbon released due to the increase in irrigation energy also increases to 87432.5 tons per year (73.7 percent). Therefore, the WEFGN index score for each of the drip irrigation, sprinkler and current status methods was 0.86, 0.31 and 0.47, respectively, and the best irrigation method in Zayandehrud basin in terms of nexus approach was drip irrigation.