LAUSR

Water use efficiency (WUE) improvements in agricultural production are of great significance to regional food security and ecological sustainability. Based on modified water footprint (WF) calculations for corn cultivation in China, WUE indices of water productivity (WP) and water efficiency (WE) for production capacity and the effective ratio of water resources were developed and quantified in the current study. Approaches to achieving national productive and effective improvements concurrently were sought by determining the spatial-temporal patterns and determinants of WP and WE during 1996–2015. The results show that the annual crop WF was estimated at 197.3 m³, including 14.1 % blue, 62.4 % green and 23.4 % gray components. WP and WE were calculated as 0.781 kg/m³ and 0.687, respectively, both of which increased over time in all subregions. Both WP and WE showed obvious spatial differences in the observed period. Low-value provinces were concentrated in the northwest and on the Huang-Huai-Hai Plain, and most high-value regions were distributed in the southeastern coastal zone. Agricultural production technology improvements contributed to WF reductions in specific areas, while meteorological elements and planting structure were the main factors affecting the spatial distribution of WP and WE. WF suppression in northwestern China and expansion of the production scale in southern China were conducive to increasing productive and effective agricultural water resource use in corn cultivation nationally. Agricultural production technology progress and crop spatial arrangement optimization are equally important to agricultural WUE enhancement in the WF framework.