Consumptive water use in cropland and its partitioning:A high-resolution assessment

Spatially explicit assessments of consumptive water use (CWU) are still at an early stage, and parti-tioning of CWU has rarely been studied on large scales. In this article, CWU is assessed for China’s cropland with a spatial resolution of 30 arc-minutes. The partitioning of CWU is discussed through the simulation of transpiration ratios. The total CWU for Chinese cropland was 839 km3/a during 1998―2002. Spatial distribution of CWU is closely related to cropland area and crop production with the highest CWU in the North China Plain. Transpiration accounts for two-thirds of CWU. The transpiration ratio is affected by precipitation and irrigation. Transpiration ratios are higher in irrigated systems than in rainfed systems when precipitation is low. Competition of water use will impose pressure on China’s irrigation systems in the near future, and it will have a far-reaching effect on the partitioning of consumptive water use. Attention should be paid to green water management and technological improvements to guarantee China’s water and food security.