Guan'gai paishui xuebao (Jun 2021)
Spatial Pattern of Irrigation Water Demand Based on GF-1 Satellite Data and P-M Method
Abstract
【Objective】 Analyzing the temporal and spatial distribution of crop water demand and irrigation water demand.This study provides basic data and technical support for irrigation water management and the implementation of the strictest water resources management system in Xinjiang. 【Method】 We constructe the NDVI multi temporal sequence was based on the GF-1 satellite data. Used the supervised classification method to extract the crop planting structure in Aksu River Oasis. Combined with penman Monteith formula and GIS spatial analysis function, the temporal and spatial distribution characteristics of crop water demand and gross irrigation water demand in Oasis were analyzed. 【Result】 Under the multi temporal NDVI sequence, the maximum likelihood method was the best, with an overall accuracy of 93.08% and Kappa coefficient of 0.913, which could meet the requirements of large area classification. The results showed that the grain crops (rice, corn, wheat) were mainly distributed in Wushi and Wensu in the upper reaches of the basin, economic crops (cotton) were mainly distributed in Aksu, Alar and some farms of the first agricultural division, and fruit trees were mainly distributed in Aksu and Awati. The temporal and spatial distribution of crop water requirement and irrigation amount in the watershed is quite different. In terms of time, the water demand in spring and summer accounted for about 70% of the annual water demand; in terms of space, the water demand and irrigation amount in the area near Wensu county were significantly higher than those in other areas. At the same time, the water demand of the same crop is also different in different regions. The range of water demand of cotton is 704.4～808.8 mm, and the difference of water demand in different regions is about 100 mm in crops. 【Conclusion】 The method of combining multi temporal NDVI and supervised classification based on GF-1 data can realize the extraction of crop planting structure in large area. There are obvious differences in crop irrigation requirement in space and time in oasis area of Aksu basin. The spatial distribution map of crop water demand and irrigation amount can provide reference for the formulation of irrigation schedule and the optimization of agricultural water resources pattern.
Keywords
