An Analytical Study on the Measurement of Agricultural Net Irrigation Water Requirements

Abstract

The net irrigation water requirement (NIWR) in the irrigated area is the “terminal” of water-use efficiency and the basis for implementing quota management and water-saving incentives. Also, it is significant for farmland water management and water conservation in irrigated areas. In light of the average water consumption per mu and the crop area, which are two key indicators of the NIWR, this paper adopts the field selection measurement method and the statistical method based on the image patches achieved by China’s third national land survey to acquire the data of water consumptions and crop areas. In this case, four principles of field selection are proposed, including “basic requirements”, “moderate size”, “controllable water inflow”, and “measurement practicality”, in an attempt to increase the number of fields selected for analysis. In addition, based on the image patches, the “complete investigation” and the “typical investigation” are suggested for irrigated areas at different scales to determine the crop areas, which are proven practicable and available for evaluating the water-use efficiency of irrigated areas at different scales.