水稻灌区农业面源污染物迁移转化规律模拟研究

发布时间：2018-11-10 23:35

【摘要】：模拟水稻灌区中非自然水文过程及其驱动下的面源污染物迁移转化过程对了解水稻灌区面源污染形成机理以及污染控制具有重要的意义。将水稻灌区水文过程分为陆面水文过程和排水沟道水文过程,采用均衡法模拟陆面水文过程中稻田深层渗漏水量以及氨氮(NH4~+)、硝氮(NO_3~-)和磷酸根(PO_4~(3-))的渗漏通量,在此基础上,基于非稳定饱和渗流方程计算稻田深层渗漏过程所形成的侧向排水过程,作为排水沟道水文过程的输入项,基于动力波方程和一阶动力学方程描述了水稻灌区排水网络下的面源污染物运移和转化过程,提出了水稻灌区农业面源污染物迁移转化模型。根据前郭灌区2008—2009年的监测数据对模型渗流过程、主要面源污染物迁移转化过程参数进行率定,采用2010年的监测资料对模拟结果进行了验证。结果表明,基于所提出的方法模拟了稻田和排水沟道2个水文过程中NH4~+,NO_3~-和PO_4~(3-)的质量浓度峰值过程的差异,实现了水稻灌区陆面水文和排水沟水文过程的耦合。稻田水层中模拟NH4~+,NO_3~-和PO_4~(3-)的Nash-Sutcliffe系数分别为0.772、0.758和0.709,相对均方根误差(RMSE)分别为0.042、0.050和0.071,排水系统中模拟NH4~+、NO_3~-和PO_4~(3-)污染物的Nash-Sutcliffe系数分别为0.645、0.704和0.854,相对均方根误差(r RMSE)分别为0.072、0.060和0.031。所提出的方法可有效地模拟稻田渗流过程和排水过程中的面源污染物迁移转化过程。
[Abstract]:It is important to simulate the unnatural hydrological process and the transport and transformation of non-point source pollutants driven by rice irrigation area in order to understand the formation mechanism and pollution control of non-point source pollution in rice irrigation area. The hydrological process of rice irrigated area was divided into land surface hydrological process and drainage channel hydrological process. The equilibrium method was used to simulate the water leakage and ammonia nitrogen (NH4~) in the deep layer of paddy field during the land surface hydrological process. The leakage fluxes of nitrate (NO_3~-) and phosphate (PO_4~ (3-) were calculated based on the unsteady saturated seepage equation. As the input of drainage channel hydrological process, based on the dynamic wave equation and the first order dynamic equation, the transport and transformation process of non-point source pollutants under drainage network in rice irrigation area were described, and the model of agricultural non-point source pollutant migration and transformation in rice irrigation area was put forward. According to the monitoring data of Qianguo Irrigation District from 2008 to 2009, the model seepage process and the parameters of the main non-point source pollutant migration and transformation process were determined, and the simulation results were verified by the monitoring data in 2010. The results show that the difference of peak mass concentration of NH4~, NO_3~- and PO_4~ (3-) in two hydrological processes of paddy field and drainage channel is simulated based on the proposed method. The coupling of land surface hydrology and drainage ditch hydrology was realized in rice irrigation area. The Nash-Sutcliffe coefficients of simulated NH4~, NO_3~- and PO_4~ (3-) in paddy water layer were 0.758 and 0.709, respectively. The relative root mean square error (RMSE) of simulated NH4~, NO_3~- and PO_4~ (3-) were 0.042 ~ 0.050 and 0.071, respectively. The Nash-Sutcliffe coefficients of NO_3~- and PO_4~ (3-) pollutants were 0.645-0.704 and 0.854, respectively, and the relative root mean square error (r RMSE) were 0.072 ~ 0.060 and 0.031, respectively. The proposed method can effectively simulate the seepage process of paddy field and the process of transport and transformation of non-point source pollutants in drainage process.
【作者单位】：西藏农牧学院;
【基金】：西藏自治区科技厅农牧业科技成果转化与示范项目;西藏自治区科技厅科技重大专项(Z2016C01G01/07) 国家重点研发项目(2016YFC0402405) 国家自然科学基金项目(51379152,91647109,51679257)
【分类号】：X52;X71

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