为获得适用于淮北平原农作物生长期有效降水量估算的方法，利用五道沟实验站地下水位控制埋深为1.0 m、1.5 m和2.0 m，测筒面积为2.0 m2和4.0 m2，土样为原状砂姜黑土的6套大型地中蒸渗仪，以小麦、夏玉米为对象，分别设计3个水平、6个处理，开展为期3年的有效降水量观测试验研究。利用长系列资料，获得地下水位控制埋深为1.0 m、1.5 m及2.0 m共3个水平在3种实测典型年，即p为5.1％、48.7％和94.9％的有效降水量及其有效降水系数分析结果，计算出不同时段，即月、季或年的有效降水量。
In order to get an estimation method for the effective precipitation in Huaibei plain during the crop growth period, an experiment lasting for three years was designed based on three levels and six processing according to the survey of the effective precipitation. In the experiment, wheat and summer maize were taken as objective, and the area of the six set measurement tubes of the earth lysimeter were 2.0 m2 and 4.0 m2 whose buried depth under control of the groundwater are 1.0 m, 1.5 m and 2.0 m in Wudaogou Key Laboratory of Water Resources. The soil sample is lime concretion black soil. Based on a long series document, the analysis of the effective precipitation and the effective precipitation coefficient in different groundwater burying depth (1.0 m, 1.5 m and 2.0 m)were gotten at three kinds of typical annuals (5.1％, 48.7％ and 94.9％), and the effective precipitation at different time, that is, month, quaternary and year was estimated.