Climate change decreased the effect of meltwater on cotton production in the Yarkant river basin of arid northwest China

Glacial and snow meltwater from high mountains plays a critical role in the regulation of river discharge and impacts the irrigation of croplands in arid regions. In this study, the variable infiltration capacity (VIC)-glacier hydrological model combined with a crop yield model (CROPR model) was used to investigate the significance of meltwater to irrigation and cotton yield in the Yarkant River basin of arid Northwest China. The results indicated that the annual meltwater followed an increasing trend at a rate of 0.5 mm/10 a during 1960-2017. The warm-dry to warm-wet climate during recent decades has been driving the increasing annual total discharge and meltwater and the decreasing total irrigation, irrigation from meltwater and contribution of meltwater to cotton yield. The effect of precipitation on irrigation from meltwater and the contribution of meltwater to cotton production were greater than those of temperature. Increasing precipitation decreased the impact of meltwater on irrigation and cotton production. This study is helpful for the scientific management of cryospheric water resources and addressing the risk of water shortages in the arid region of Northwest China.