| Abstrakt: |
Spatio-temporal analysis of crop water requirement and crop irrigation water requirement is crucial to the optimal allocation of water resources and the formulation of irrigation systems. The objective of this study is to understand the spatio-temporal characteristics and influencing factors of the water requirement during the growth period and irrigation water requirement of the main crops in Xinjiang, cotton, spring wheat, winter wheat, and corn. Based on the daily meteorological observation data from 1960 to 2020, the Penman-Monteith formula and the single crop coefficient method were adopted in this study, and Mann-Kendall (TFPW-MK) of Detrended Preset White (TFPW) was used to study the changing characteristics of water requirement of four crops. The temporal and spatial evolution trend of crop water requirement and irrigation water requirement were predicted by rescaled range (R/S) analysis. Using the principle of important covariate feature identification of the random forest model, the importance ranking of meteorological factors and crop water requirement was analyzed, and the causes of changes in crop water requirement were explored. The results show that: 1) the water requirement of major crops in Xinjiang had generally shown a trend of "increase first, then decrease and then increase" for 61 year. The order of crop water demand and irrigation water requirement from large to small was: cotton > corn > winter wheat > spring wheat. In terms of space, there was a spatial distribution of "Southern Xinjiang>Northern Xinjiang, Southeast>Northwest, East>Western". The variation range of water requirement for major crops was: cotton 381.20-991.20 mm (mean 654.94 mm), corn 350.26-924.48 mm (mean 607.98 mm), spring wheat 361.96-709.69 mm (average 464.89 mm), winter wheat 266.47-753.62 mm (average 495.7 0 mm). The range of irrigation water requirement was: cotton 49.49-975.88 mm (average 563.19 mm), corn 52.47-910.85 mm (average 530.18 mm), spring wheat 42.58-701.29 mm (average 409.28 mm), winter wheat 21.94-741.77 mm (average 418.26 mm). Since the middle and late 1980s, irrigation water requirement decreased more than water requirement. 2) According to the TFPW-MK analysis, in the past 61 years, the water requirement of 12 stations mainly distributed in the northern edge of the Tarim Basin, including Shaya and Aksu, and Baekol in the eastern Xinjiang, showed an upward trend. The water requirement of 27 stations in Karamay in Xinjiang and Artux in southern Xinjiang gradually decreased; the rest of the stations fluctuated up and down. 3) In the prediction of future water demand using the R/S method, four crop water demand and irrigation water demand at Tacheng, Toli, Fuyun and Urumqi stations in northern Xinjiang, Baekol in eastern Xinjiang, and Shaya, Wuqia, Tazhong, Qiemo and Kalpin stations in southern Xinjiang will decrease in the future, while spring and winter wheat water demand at Hongliuhe, Baekol and Bayanbulak in eastern Xinjiang will show an increasing trend in the future. 4) During the crop growth period, wind speed and temperature were the most important factors affecting the water requirement of major crops in Xinjiang, while precipitation was the least important factor for the water requirement of major crops in Xinjiang. This research comprehensively provides decision-making and basis for the formulation of high-efficiency agricultural water use and irrigation measures in Xinjiang. [ABSTRACT FROM AUTHOR] |
