Distribution and drivers for blue water dependence in crop production in China, 1999–2018

Abstract

The process of blue water used in crop cultivation has both natural and economic properties due to the intervention of irrigation facilities. This study revealed crop water use (CWU) from 1999 to 2018 in each province of China based on water footprint theory, and then established the blue water dependence index (BDI) to evaluate the dependence of agricultural cultivation on irrigation water from the perspective of water withdraw, and conducted a spatial and temporal pattern analysis.The influencing factors and structural pathways of BDI were explored using least squares structural equation modeling (PLS-SEM) at national and regional scales. Results indicated that the annual amount of water used for crop production in China exceeded 900.0 Gm³. The growth in CWU from 1999 to 2018 for cash crops and grain crops was 145.4 Gm³ and 74.4 Gm³, respectively.BDI of all crops was 0.281 over the study period in China, with grain crops being 2.6 times more dependent on blue water resources than cash crops. Xinjiang, with annual average BDI of 0.716, 0.805, and 0.620 for all, grain and cash crops, respectively, has the highest irrigation demand. The PLS-SEM results showed a significant causal relationship between the economy and BDI, with obvious regional differences in structural path analysis. Based on the analysis of agricultural water use, the regions can adjust the structure of crop cultivation, optimize the allocation of water and soil resources, expand the cultivation of fodder grains and promote steady economic growth, to achieve a ''win-win'' situation of ensuring food security and sustainable use of agricultural water resources.

Keywords

• Crop water use
• Blue-green water
• Water footprint
• PLS-SEM
• Irrigation management