| 非饱和坡面水分与氮素迁移耦合模型与应用 |
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| 引用本文： | 朱焱,刘琨,刘昭,毛威,杨金忠,伍靖伟.非饱和坡面水分与氮素迁移耦合模型与应用[J].农业工程学报,2020,36(3):126-134. |
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| 作者姓名： | 朱焱 刘琨 刘昭 毛威 杨金忠 伍靖伟 |
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| 作者单位： | 江西省水土保持科学研究院江西省土壤侵蚀与防治重点实验室,南昌 330029;武汉大学水资源与水电工程科学国家重点实验室,武汉 430072;湖北省水利水电规划勘测设计院,武汉,430072;江西省水土保持科学研究院江西省土壤侵蚀与防治重点实验室,南昌,330029;武汉大学水资源与水电工程科学国家重点实验室,武汉,430072 |
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| 基金项目： | 国家重点研发计划课题（2018YFC0407602）；江西省自然科学基金（20192BAB213022）；江西省土壤侵蚀与防治重点实验室开放基金（KFJJ201801） |
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| 摘 要： | 目前对坡面径流氮素流失的研究以解析方法为主,难以描述坡面不同位置水分及氮素的变化情况,且较少关注水分入渗造成的氮素迁移。为了描述非饱和坡面上的降雨-径流-入渗及氮素迁移过程,该文构建了坡面尺度数值模拟模型。对于水分入渗,采用运动波方程描述坡面产流过程,采用Green-Ampt公式描述坡面入渗过程。对于氮素迁移,将研究区离散,采用混合层理论对每个离散区域建立质量平衡方程。通过与坡面水分、氮素运移试验数据的对比验证了本模型的正确性。开展室内土槽坡面径流试验,观测数据与数值模拟结果的对比表明,本模型水分、铵态氮、硝态氮计算相对误差分别小于15%、5.5%和32%,质量误差均小于0.02%,验证了本模型较好的计算精度和质量误差控制。
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| 关 键 词： | 氮 土壤 模型 混合层理论 地表径流 |
| 收稿时间： | 2019/11/28 0:00:00 |
| 修稿时间： | 2020/1/3 0:00:00 |
Coupling model for moisture and nitrogen transport on unsaturated slope and its application |
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| Zhu Yan,Liu Kun,Liu Zhao,Mao Wei,Yang Jinzhong and Wu Jingwei.Coupling model for moisture and nitrogen transport on unsaturated slope and its application[J].Transactions of the Chinese Society of Agricultural Engineering,2020,36(3):126-134. |
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| Authors: | Zhu Yan Liu Kun Liu Zhao Mao Wei Yang Jinzhong and Wu Jingwei |
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| Institution: | 1. Jiangxi Provincial Key Laboratory of Soil Erosion and Prevention, Jiangxi Institute of Soil and Water Conservation, Nanchang 330029, China; 2. The State Key Laboratory of Water Resource and Hydropower Engineering Science, Wuhan University, Wuhan 430072, China;,3. Hubei Provincial Water Resources and Hydropower Planning Survey and Design Institute, Wuhan 430064, China;,1. Jiangxi Provincial Key Laboratory of Soil Erosion and Prevention, Jiangxi Institute of Soil and Water Conservation, Nanchang 330029, China;,2. The State Key Laboratory of Water Resource and Hydropower Engineering Science, Wuhan University, Wuhan 430072, China;,2. The State Key Laboratory of Water Resource and Hydropower Engineering Science, Wuhan University, Wuhan 430072, China; and 2. The State Key Laboratory of Water Resource and Hydropower Engineering Science, Wuhan University, Wuhan 430072, China; |
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| Abstract: | The major methods to describe the nitrogen loss caused by slope runoff were based on the analytical method, which failed to describe the difference in moisture and nitrogen transport processes at different points of the slope. Moreover, the previous researchers kept the focus on the nitrogen loss by the slope runoff and focused less on the nitrogen along with the infiltration. To overcome the disadvantages, a slope scale numerical model was developed to describe the slope rainfall-runoff-infiltration processes and the nitrogen transport processes in this study. For the water movement module, the one-dimensional kinematic wave equation described the slope runoff process, while the Green-Ampt equation described the infiltration process. The Preissmann weighted implicit four-point scheme solved the water movement governing equations numerically. For the solute transport module, the study region was divided into a series of sub-regions and the mass balance equations developed for each sub-region based on the mixing layer theory. Both the mass balance equations for NH+ 4-N and NO- 3-N was formed and the nitration process, denitrification process, loss caused by slope runoff and infiltration was considered for NH+ 4-N, while only the nitration process, loss caused by slope runoff and infiltration was considered for NO- 3-N. Two published experiments were used to evaluate the performance of the developed model. The results demonstrated that the developed model had a satisfactory calculation accuracy and kept an excellent mass balance budget. Moreover, two indoor soil tank modeling experiments with the unsaturated initial conditions were carried out. The two indoor soil tanks had different slope angles, one was 8.85° and the other was 7.55°. Both the experimental results and the numerical calculation results analyzed the water movement and the nitrogen transport processes. The RMSE value and ARE value of the slope runoff for the first soil tank were 5.3×10-7 m2/s and 11.6%, while the RMSE value and ARE value of the slope runoff for the second soil tank were 8.6×10-7 m2/s and 15.0%. The mass balance error of the water balance module for the first soil tank and the second soil tank were 1.87×10-2 % and 7.22×10-3 %, respectively. The results indicated that the satisfactory performance of the water movement module. The RMSE value and ARE value of the concentration of NH+ 4-N and NO- 3-N in runoff for the first soil tank were 0.016 mg/L and 5.5%, and 1.41 mg/L and 31.9%, while the RMSE value and ARE value of the concentration of NH+ 4-N and NO- 3-N in runoff for the second soil tank were 0.010 mg/L and 3.5%, and 0.23 mg/L and 10.6%. The mass balance error of the NH+ 4-N and NO- 3-N for the first soil tank were 4.99×10-4 % and 4.53×10-4%, while the mass balance error of the NH+ 4-N and NO- 3-N for the second soil tank were 4.55×10-4 % and 1.25×10-3%. The results indicated that the nitrogen transport module also had satisfactory performance. Besides, the unsaturated hydraulic conductivity had a great influence on the infiltration quantity. Moreover, the NH+ 4-N had a strong adsorption capacity, which led to an increase of the concentration of NH+ 4-N in the mixing layer, while the NO- 3-N had a weak adsorption capacity and the concentration of NO- 3-N in the mixing layer decreased obviously under the effect of runoff and infiltration processes. |
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| Keywords: | nitrogen soils model mixing layer theory surface runoff |
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