More water, more production? Evidence from Chinese agricultural production

Against the background of global food crisis and climate change, water scarcity and food insecurity are two major challenges facing the world at present. In this regard, irrigation water comprises a substantial portion of overall water use. Using β convergence models, this study investigates the relationship between irrigation water and food production (including grains and vegetables) based on physical water productivity (PWP). The results show that the absolute β convergence model supports the presence of convergence in grain and vegetable PWP across China. Meanwhile, the conditional β convergence model confirms convergence within each provincial-level administrative region. Additionally, the club convergence model reveals convergence ingrain and vegetable PWP at the local level. These imply that although water plays a major role in agricultural production, continuously increasing water intake will not significantly enhance productivity. These findings can inform agricultural water redistribution and deficit irrigation practices. This study’s main contributions are as follows: first, the existence of convergence ingrain and vegetable PWP at different spatial scales is confirmed. Second, the conventional view that increasing water increases production is challenged. Third, the findings have implications for policies in support of deficit irrigation.