随着降水量的变化,农业用水量变化差异较大,而如何确定不同降水频率之间农业用水量的关系一直是难点之一。结合降水及单位灌溉面积用水量的实际数据,将全国划分6个区,计算出各个区域农田单位灌溉面积用水量不同频率与多年平均相对应的调节系数。选取江苏省作为案例进行应用,根据江苏省的农业发展、现状水资源概况确定农田单位灌溉面积用水量不同频率与多年平均的调节系数,其中降水频率70%~80%时的调节系数最大,为1.12;95%下的调节系数最小,为0.81;结合相关规划预测2020年降水频率75%下农田单位灌溉面积用水量7 210 m³/ hm²,95%下农田单位灌溉面积用水量5 197 m³/ hm²。研究成果可为不同水平年农业用水的计算提供参考依据。

Agricultural water consumption varies drastically with the change of precipitation. Determining the relation among agricultural water consumption in different precipitation years has always been a difficulty. In this article, according to the actual data of precipitation and irrigation water consumption per unit hectare, the ratio of irrigation water consumption at a given precipitation frequency to multi-year average irrigation water consumption (defined as regulation coefficient)is calculated for six irrigation regions. Furthermore, according to the status quo of agricultural development and water resources in Jiangsu Province, the values of regulation coefficient at different precipitation frequencies are obtained. Results show that the maximum regulation coefficient is 1.12 at 70%-80% precipitation frequency, and the minimum regulation coefficient is 0.81 at 95% precipitation frequency;according to planning, the irrigation water consumption in 2020 at 75% precipitation frequency is estimated to be 7 210 m³/hm², and 5 197 m³/hm² at 95% precipitation frequency.