Spatiotemporal variation characteristics of crop heat stress in Xinjiang

With the continuous increase in global temperatures and the frequent occurrence of extreme climates, crop heat stress has become increasingly common, severely affecting regional food production. Based on the China Regional Surface Meteorological Elements Driving Dataset, we systematically analyzed the spatiotemporal variation characteristics of crop heat stress in the cultivated areas of the Xinjiang Uygur Autonomous Region from 1979 to 2020. Three heat stress indices, namely, cumulative heat stress days (AHSD), heat stress intensity (HSI), and heat stress degree days (HDD), were adopted, along with the application of the Mann-Kendall trend test, Sen’s slope analysis, and spatial autocorrelation method. The results showed that the level of crop heat stress in Xinjiang had increased markedly, with AHSD, HSI, and HDD increasing at rates of 12.3 d·(10a)-1, 0.3 ℃·(10a)-1, and 60.2 ℃·d·(10a)-1 per decade, respectively. HSI and HDD in northern Xinjiang were higher than those in southern Xinjiang, whereas AHSD was longer in southern Xinjiang. Significant differences were observed in the spatial distribution of heat stress: the Turpan Region was the most severely affected by heat stress (with AHSD reaching 162.8 d and HDD reaching 710.6 ℃·d), whereas the Yili River Valley and Altay Region were the least affected (with AHSD ranging from 0.2 to 49.1 d and HDD ranging from 0.3 to 85.4 ℃·d). The impact intensity of heat stress was relatively high in cultivated area-concentrated regions, such as the border area between Shihezi City and Tacheng Region, the Turpan Basin, and the Hami Oasis, accompanied by a pronounced upward trend. The global Moran’s index indicated that heat stress exhibited a significant positive spatial correlation (P<0.001), showing agglomeration patterns of “high-high” and “low-low” heat stress values. This study can provide a scientific basis for Xinjiang’s agriculture to adapt to climate change, optimize crop layout, and formulate stress-resistant cultivation measures.