水-土耦合的稻田磷素动态流失模型

Water-soil coupled phosphorus loss dynamic model for paddy fields

磷是湖泊富营养化的限制性因子,稻田排水损失是磷素的重要来源.为了精确计算稻田磷素损失量,从质量守衡原理出发,考虑土壤磷的矿化和固定、淋溶、水稻吸收等作用,结合土壤胶体对磷的吸附解吸速率公式,建立了水土耦合的稻田磷素动态模型,并采用田间实测数据对模型参数进行了率定和验证,同时还对关键参数进行了灵敏性分析.计算结果表明,模型能较好地模拟田面水及渗漏水中溶解态无机磷(DIP)浓度的动态变化.

Phosphorus is the restrictive factor of lake eutrophication, and the runoff loss of paddy fields is the main source of phosphorus pollution, so exact calculation of phosphorus loss is of great importance to remediation of non-point source pollution. A water-soil coupled phosphorus loss model for paddy fields was developed according to the principle of mass balance with consideration of mineralization, immobilization, eluviation, and rice absorption of phosphorus. In addition, a formula of adsorption-desorption rate of phosphorus was introduced into the model. The model was calibrated and verified with the measured data of water quality parameters of paddy fields. Furthermore, a sensitivity analysis was carried out on several key parameters. Calculated results show that the variation of dissolved inorganic phosphorus (DIP) in field surface water and leakage water can be simulated dynamically by the model.