| Cite this article: | 黎曙,王鹏翔,周祖昊.冻土融化过程中农田污染物析出入河特性研究[J].灌溉排水学报,0,():-. |
| Li Shu,Wang Pengxiang,zuhao_zhou@sina.com.冻土融化过程中农田污染物析出入河特性研究[J].灌溉排水学报,0,():-. |
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| Characterization of the discharging processes of agricultural non point source pollutants from soil entering rivers during the soil thawing period |
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Li Shu1, Wang Pengxiang2, zuhao_zhou@sina.com2
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1.Xining Division of Hydrology and Water Resource, the Yellow River Water Resource Conservancy Commission;2.State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin, China Institute of Water Resources and Hydropower
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| Abstract: |
| 【Objective】The objective of this study is to characterize the processes of water flow and pollutant fluxes that enter rivers from soil in the catchments with different underlying surface conditions during the thawing period. 【Method】Through 3 y of in-site experiments conducted in the small river basin of Heidingzi, changchun, we measured water content and soluble pollutions (i.e., NH4+-N, NO3--N and SP) concentrations in soil and flow rates and pollutions fluxes at the outlet of the catchments. The contribution of the water and pollutants in the various soil depths and positions in the catchment to the river fluxes were analyzed using the isotope. 【Result】Result showed that, in the catchment in which maize cultivation fields were dominant, the discharged soil water reached peak in the beginning of the soil melt. As peak water flow occurred and the pollutants transported into the rivers simultaneously formed the peak pollutant flux, the fluxes of NH4+-N, NO3--N, and SP were primarily affected by the soil water flow movement, The discharged soil water and pollutants rapidly decreased after the peak exudation of soil water flow. In the catchment in which paddy fields were dominant, the relative concentrations (i.e., ratio of river pollutant concentration to mean concentration in the thawed soil) of NH4+-N and NO3--N showed a decreasing trend while the SP relative concentrations maintained stable. Then the relative concentrations increased as the exudation water increased until the water flow exudation reached its peak,. after the soil water exudation peak, the water and pollutant exudation significantly decreased. Furthermore, as the water exudation decreased, the differences in relative concentrations between different pollutants increased. In the paddy fields, the impacts of input energy on the water export was dominant. The migration capacity of NH4+-N and NO3--N in the soil also increases with the input energy. In corn fields, the impacts of input of energy on the pollution transformation capacity was more significantly. In all catchments, the variation range of soil pollutant concentrations exceeded that of river pollutant concentrations. During thawing period, the source regions of water and different pollutants that entered the rivers as well as the water content and pollutants that entered the rivers from different soil depths were different. Controlling of water export is a suitable method to reduce pollution export since pollution export increased nonlinearly with water export in both paddy and corn field.【Conclusion】Controlling the soil water content and the of pollutants concentration have the most significant effects on reducing the exported pollutions from the thawing soils into the river in the paddy and corn fields, respectively. |
| Key words: Thawing period; Agricultural non point source pollutions;; Exclude process of water and pollution from soil to stream. relative concentration |
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