Mapping irrigation area of winter wheat farmland in North China Plain using MODIS remote sensing data

Abstract

North China Plain was the most important cropping region in China with severe challenges of water shortage. Cropping in the plain required large amount of irrigation water to support harvest. However, water resource was very limited due to high evaporation and unbalanced precipitation. Both surface and underground water resources in the region had been over-extracted. Since agriculture consists of the largest component of water uses, mapping irrigation area for estimation of agricultural water demand was urgently required to improve the administration of water resource for effective utilization in the region. We presented our systematic investigation of mapping the irrigation area in the plain using MODIS remote sensing data. Winter wheat had been identified as the main cropping systems requiring intensive irrigation during the growing season from March to early June. The normalized difference of vegetation index (NDVI) had been used to identify winter wheat and forest, which could then be used as the input for irrigation mapping. Then Vegetation supply water index (VSWI) had been used for identifying irrigated area in winter wheat field, which combined the information of temperature and growing condition of vegetation together. According to our study in North China plain, irrigation area could be properly mapped for estimation of agricultural water demand using the MODIS data. Total irrigation area of the region was about 5.9 million ha in 2006. The results indicated that the spatial variation of irrigation area was very obvious in the region. More intensive irrigation could be observed in southern Hebei and northeast Henan of the region. Irrigation percentage in these areas might reach up to 70% for winter wheat in 2006. Therefore, our study demonstrated that MODIS data could be useful for irrigation mapping in regional scale.