Extraction of Crop Structure and Analysis of Water Supply and Demand in Irrigation Area of Yellow River Diversion Based on Sentinel-2 Image
Under the background of strict control of water consumption index in the Yellow River Basin,taking Kenli District of Dongying City,Shandong Province as an example,NDVI time series of crop growth period was built by using Sentinel-2 remote sensing images in 2022,and the crop planting structure in the irrigation area was extracted by decision tree classification method.Based on the meteorological data of Kenli Station and Penman-Monteith formula,the water demand characteristics of each crop during 1973 to 2022 were analyzed,and the area results of each crop interpreted by remote sensing images were used as the base.The total irrigation water demand of crops in 2022 under different precipitation guarantee rates(5%,25%,50%,75%and 95%)was calculated,and the balance between supply and demand of irrigation water resources was explored combined with the irrigation water index allocated to crops in 2023.The results show that the deci-sion tree classification method based on NDVI time series can effectively extract the planting structure of crops,the overall classification ac-curacy is 85.07%,and the Kappa coefficient is 0.819,which can meet the research of crop irrigation water requirement.The net irrigation water requirement of crops is fluctuated greatly from year to year,and the supplementary irrigation amount of rice and winter wheat ranked first and second among all crops,with an average of 913 mm and 410 mm respectively.For summer corn and summer soybean growing in rainy season,the amount of supplementary irrigation is smaller and the average irrigation demand is lower.The irrigation water deficit alloca-ted in the study area in 2023 is 2.355 million m3 at 50%guarantee rate,and 17.545 million and 22.615 million m3 at 75%and 95%guaran-tee rates.
Sentinel-2 imageplanting structurewater demand characteristicsirrigation water supply and demandYellow River diversion irrigation area
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