Potential Impacts of Climate Variation on Potato Field Evapotranspiration: Field Experiment and Numerical Simulation of Potato Water Use in an Arid Site

Climate change would significantly affect crop evapotranspiration processes. Many studies have been conducted for various crops. However, there is a lack of sufficient observational evidence on how climate change would influence potato evapotranspiration. In this paper, an experimental potato field in Maowusu Desert, northwest of China, was used to investigate the effect of climate change on potato evapotranspiration. Temporal variations in reference evapotranspiration (ET0) were comprehensively investigated during 1954–2013, which shows that annual temperature and ET0 had significant increasing trends in the past 60 years. Meanwhile, an experimental crop of potato was grown in Maowusu Desert to investigate water‐soil‐air‐plant‐human nexus in 2016, and a HYDRUS‐1D model for the unsaturated flow in a potato field was calibrated and validated with measured soil water tensions and soil water contents at various depths during the potato growing periods from 8 to 16 August 2016 and from 6 September to 3 October 2016, respectively. The model computed the actual potato evapotranspiration (ETa) as 183 mm during the whole growing period from 5 June to 3 October 2016. The groundwater contribution to potato water use was calculated to be 320 mm during the growing season in 2016. As the atmospheric temperature increases, the reference crop evapotranspiration increases, the actual potato evapotranspiration increases too. The actual potato evapotranspiration increase with temperature increase will lead to a bigger water resource pressure in this area. The study results provide the basis for managing crop irrigation in the region in the future. Key Points Annual temperature and ET0 have significant increasing trends during the last 60 years A HYDRUS‐1D model for potato water use was successfully calibrated and validated with field measurements Increase of atmospheric temperature in future would lead to the increase of actual potato ET and increase of water use for potato growth