Refined accounting method for irrigation water use of food crops in water-scarce regions and its application

Abstract

To precisely quantify deficit irrigation water use for food crops in water-scarce areas, this study proposes a method ological framework that starts from the crop's intrinsic growth water requirements and the physical mechanisms of irrigation process. It accounts for the dynamic variation of deficit irrigation patterns in response to precipitation, determines the net irrigation water use quota under different precipitation conditions during key growth stages, and incorporates the analysis of irrigation water use efficiency coefficients and cultivated areas across different irrigation method. This framework was applied to wheat in Qingdao City to calculate its irrigation water use from 2011 to 2022. The result show that the multi-year average net irrigation water use quota for wheat in Qingdao was 1 035 m³/hm²(2011-2022), with significant interannual fluctuations; the average annual irrigation water use was 207 million m³, exhibiting an initial decline followed by an increasing trend over time. Pingdu recorded the highest water use, while Chengyang had the lowest; the multi-year average gross irrigation water use quota was 1 575 m³/hm², which were approximately 70% of the local agricultural water demand quota standard. Pingdu and Laixi City showed higher gross water use quota. The findings indicate that precipitation during growth stages and water supply conditions are the primary factors influencing wheat irrigation water use in Qingdao. These result can serve as a reference for water use statistics verification and irrigation management in the study area.

Keywords

irrigation water use / insufficient irrigation / refined accounting method / water-scarce regions / food crops