麦田在降雨入渗和排水条件下化肥流失的试验研究

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

Experimental Investigation of Nitrogen Losses in Effluent from Drained Field of Winter Wheat

In the humid plain areas in South China, a rotation cropping pattern of winter wheat paddy rice is widely applied. For control of water logging, pipe drainage were usually installed. For investigating nitrogen losses from drained lands and its impact on environment, field tests were carried out at Qingpu Irrigation and Drainage Experimental Station. The investigated data in growth season of winter wheat show that under conditions of shallow water table, content of nitrate nitrogen in soil profile below the water table is comparatively small. As a result, leaching losses of nitrogen constituted only a small part of the total nitrogen losses from the drained lands, although some peaks of concentration of nitrate and ammonium nitrogen were also observed together with peaks of drainage flow during rainfall events with high intensity.