Modelling the crop water-satisfied degree on the grid scale: A CropWRA model and the case study of Hanjiang River Basin, China

Abstract

An assessment model for the satisfied degree of crop water requirements (CWR) on the grid scale, the CropWRA model, is developed to support precise management of agricultural water resources. On the grid scale, we urge that the CWR satisfied degree is not only rested with the abundance of water resources in a region, but also related to crop types, growing periods, water accessibility, etc. The CropWRA model also consists of corresponding indexes such as the CWR characteristics, crop planting combination and proportion, available water of agricultural production, water accessibility, etc. In this case study, the CWR satisfied degree of main food crops is evaluated with DEM data, hydrological data, meteorological and climate data, crop experiment and observation data, and statistical data in Hanjiang River Basin, China. In general, the results show that agricultural water resources can satisfy the CWR but the spatial differences are profoundly remarkable. The CropWRA index varies from -20% to 200%, and this difference is the comprehensive effects caused by the topography, river system, crop planting combination, land use, and water resources composition, etc. CropWRA model reveals the spatial differences in the relationships of CWR supply and demand and can provide the data support for precise water resource allocation.