Irrigation water consumption of irrigated cropland and its dominant factor in China from 1982 to 2015

Abstract

Quantifying and mapping regional and global irrigation water consumption have attracted considerable attention from researchers. The existing models cannot accurately estimate the long-term sequence of irrigation water consumption at the regional scale. Despite being among the countries with the largest irrigated areas, China has not been specifically evaluated in terms of high-resolution long-term irrigation water consumption. In this paper, an irrigated cropland water model incorporating irrigated cropland mapping, the soil water balance equation, irrigated crop phenology, and partitioning evapotranspiration products was developed to fill the knowledge gap. We found that (1) the mean annual total irrigation water consumption of irrigated cropland in China during 1982–2015 was approximately 179.43 ± 24.60 km3. (2) The continued expansion of irrigated farmland dominated (67.2% ± 5.6%) the significant increase in annual total irrigation water consumption (slope=2.03 km3 yr−1, p<0.01), followed by changes in crop management practices (16.7% ± 6.1%), and the impacts of interannual climatic variability (represented by precipitation and potential evapotranspiration in this research) were weak. (3) The annual total irrigation water consumption in the arid zone increased quicker than that in wet regions.