暗管排水稻田中氮素淋失动态混合模型及应用

Application of nitrogen leaching losses mixed simulative model in tile effluent from the drained paddy rice field.

为研究淹灌稻田在排水条件下的氮素淋失规律，根据势能理论及溶质运移理论提出了流网法与动力学方法相结合的田间水氮动态混合模拟模型该模型在暗管排水出流计算中采用叠加原理，将ＳＰＡＣ系统中异常复杂的二维水氮运移问题的求解简化为对多个流带中一维问题的求解，方法简单、实用对方法及模型的正确性进行了田间试验验证，结果表明，水稻生长期间，试验田块中氮肥淋失量为４ｋｇＮ／ｈｍ２，占总施氮量的１．３％．氮肥淋失量与农田排水条件有关，地下排水强度增大，会增加氮肥淋失量。因此，应合理进行水位管理。

In order to study the law of nitrogen leaching losses from the ponded paddy rice field under the conditions of drainage, based on the theories of potential energy and solute transposition a dynamic mixed simulative model for water and nitrogen in the field is suggested in this paper with combining the me'thods of stream-web and dynamics. During the computing of drainage, super-position principle is used to simplify the very complex resolvent for two-dimension problem of water and nitrogen transportation in SPAC system to several one-dimension Problems. The solution method is easy and practical. Some field experiments have also been carried out to demonstrate the validity of the model. The result shows that during the growing Period of paddy rice, the nitrogen leaching loss is 4kgN/hm2 in the experimental site, occupying 1 .3% of the total nitrogen used. The nitrogen leaching is related with the clrainage conditions in fields. With the increase of drainage strength, the nitrogen leaching loss also increases. Therefore, it is necessary to control the water level properly.