淹灌稻田的暗管排水中氮素流失的试验研究

为研究淹水稻田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。试验资料分析表明，在淹水层中施肥后氮素（ＮＨ＋４ － Ｎ 或ＮＯ－３ － Ｎ）浓度衰减呈指数消退。在稻、麦连作田块，水稻生长期内，氮的挥发损失较大，而通过暗管排水流失的氮素占全部损失量比例较小。当控制沟水位及田面水层的水位差，合理控制稻田渗漏量时，可减少氮肥流失量

Experimental Study of Leaching Losses of Nitrogen in Effluent from Drained Paddy Rice Field

For developing pattern of nitrogen loss in drainage effluent from paddy rice field, experiments were carried out at Qingpu Irrigation and Drainage Experimental Station. The variations of ammonium nitrogen and nitrate nitrogen concentrations in the water logged layer and in the drainage effluents show that content of nitrogen in the water logged layer decline exponentially with time after a fertilizing event, and nitrogen losses in drainage effluents are closely correlative to total drainage outflow, seepage rate and applied nitrogen fertilizer amount. In areas with silty clay soils, leaching losses of nitration from drainage effluent account for only a small part of the total nitrogen losses.