A 20-year dataset (2001-2020) of global cropland water-use efficiency at 1-km grid resolution

Cropland water-use efficiency (WUE) is an essential indicator for the sustainable utilization of agricultural water resources. The lack of long-term global cropland WUE datasets with high spatial resolution limits our understanding of global and regional patterns of cropland WUE. This study developed a long-term global cropland WUE dataset at 1-km spatial resolution from 2001 to 2020. The cropland WUE was obtained as the ratio between net primary productivity (NPP) and evapotranspiration that was retrieved from ETMonitor global evapotranspiration datasets. The global cropland NPP was estimated by subtracting plant respiration from gross primary production (GPP), which was estimated using an improved light-use efficiency model after being optimized for different global climate zones using flux-tower observation data. The generated WUE product showed good accuracy with high correlation efficiency (0.76) and low root mean square error (0.5 g C/kg H₂O/yr) compared with the ground measurements at flux towers. This dataset can be used as fundamental data to advance the efficient utilization of water use for sustainable development.