稻田中氮素流失的田间试验与数值模拟研究

Research of Field Test and Mathematical Simulation on Nitrogen Losses in Paddy Rice Fields

在上海青浦农田水利试验站进行田间试验，研究了淹灌稻田在排水条件下的氮素流失规律。在试验的基础上提出了氮素运移与转化的数学模型，对氮素的淋失动态进行了模拟研究。分析表明， 淹灌稻田的淹水层和剖面土壤溶液中氮素的主要形态为ＮＨ４＋ － Ｎ； 施肥后淹水层中氮素浓度衰减呈指数消退； 水稻生长期间， 氮肥损失的主要途径是气体损失，而淋失量相对较小。氮素损失与农田灌溉排水条件有关，因此应合理进行水位管理与调控。

In order to study the loss law of drowned paddy rice field under drainage situation, field tests have been conducted in farm water conservancy test station in Qing Pu, Shang Hai. On the experimental data, a mathematical model of nitrogen transport-transformation is presented to simulate dynamic situation of nitrogen leaching losses. The study shows that the main form of nitrogen in drowned water of drowned paddy rice field and soil solution of profile is NH 4+-N; while after fertilizing, the nitrogen concentration in drowned layer is dropped down in index. During the growth period, the main losses of nitrogen are gas losses, while the leaching losses are relative smaller. Nitrogen losses are connected with the irrigation and drainage condition in farmland, therefore, something must be done to manage and adjust the groundwater table.