在南方渍害田地区，通常是稻麦连作区，为研究这些地区在排水条件下的氮肥流失规律，在上海青浦农田水利试验站进行了田间试验。试验表明，在小麦生长期，地下水埋深较小时，氮素在土壤中，在地下水位以下土壤剖面上的硝态氮含量很小，排水农田中氮自排水暗管流失量仅占总损失量中较小部分。表明地下水中氮素大部分以Ｎ２Ｏ 和Ｎ２ 形态散失。这些试验结果将为排水条件下氮素运移转化模拟计算提供依据 In the southern China, the field of paddy fields, usually the rice-wheat continuous cropping area, was studied in order to study the law of nitrogen loss under drainage conditions in these areas. Field experiments were carried out in Shanghai Qingpu farmland water conservancy experimental station. The results showed that in the wheat growing season, when the groundwater depth is small, the content of nitrate nitrogen in the soil and the soil profile below the groundwater level is very small. The loss of nitrogen from the drained farmland in the drainage farmland accounts for only the total loss In the smaller part. It indicates that most of the nitrogen in groundwater is lost in the form of N2O and N2. These test results will provide the basis for the simulation calculation of nitrogen migration and transformation under the conditions of drainage