Impact of Practical Irrigation Practices on Farmland Climate: A Case Study of the Heihe River Oasis in Arid North‐West China

ABSTRACT This study analyses how irrigation has altered meteorological conditions and atmospheric evaporation capacity (ET pen ). The results revealed that the expansion of irrigation from 1956 to 1997 led to a greater increase in the daily relative humidity (RH) of approximately 0.73% per decade, a decrease in the ET pen of approximately 0.10 mm/day per decade, and a greater increase in daily air temperature (T 2 ) of approximately 0.01°C per decade at agricultural stations more than at natural stations. After 1998, with water‐saving irrigation, wind speed at 2 m (U 2 ) increased by approximately 0.14 m/s per decade, RH decreased by approximately 2.66% per decade, ET pen increased by approximately 0.26 mm/day per decade, and T 2 increased by approximately 0.22°C per decade. Irrigation impacts were strongest between June and August, closely linked to irrigation intensity. Specifically, for every 100 mm increase in irrigation, T 2 , underlying surface temperature (TSK), and ET pen decreased by an average of 0.11°C, 0.18°C and 0.06 mm per day, respectively, whereas RH increased by 0.60%. This study highlights the necessity of incorporating irrigation‐induced climate feedback mechanisms into agricultural water resource management and climate adaptation strategies in arid regions.