| 引用本文: | 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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| 摘要: |
| 【目的】针对不同农业区冻土融化过程中水和污染物析出入河特性及其影响因素开展研究。【方法】在吉林省黑顶子河小流域开展了三年的现场实验，选择以稻田和玉米田为主的封闭汇流区，于冻土融化期测定了汇流区内土壤水分和氨氮（NH4+-N）、硝酸盐氮（NO3--N）、和可溶性磷（SP）浓度，汇流区河道流量和污染物浓度，基于相对浓度对土壤水流和污染物析出过程进行了特征。【结果】结果表明：相比融化层土壤，河道中的NH4+-N, NO3--N和SP浓度显著减小，水流运动和污染物迁移不同步，河道中的污染物浓度相比土壤具有更大的变异性；在冻土开始融化阶段，析出水量对污染物析出量的影响最为显著，析出水量达到峰值后，土壤污染无浓度对析出量的贡献率随着析出水量减小表现出先增加后减小的趋势，随着析出水量的显著降低，污染物在土壤中的迁移能力对析出过程的影响起主要作用；析出水量和土壤中的污染物浓度分别是稻田和玉米田中影响污染物析出的主要因素；污染物相对浓度的均值和变化范围随着析出水量减小而增大；土壤近饱和的情况下，进入土壤中的能量主要用于冻土的融化的潜热消耗，且污染物在土壤中的迁移能力随能量的增加而增大，土壤含水率降低后，则用于土壤温度能加显热消耗的能量增加，土壤中污染物转化量增大，进而影响冻土中污染物的析出过程。【结论】稻田和玉米田中，控制土壤含水率和降低土壤污染物浓度对降低冻土融化期土壤中染物析出入河通量的效果最为显著。 |
| 关键词: 冻土融化期；农田面源污染物；析出通量和过程；相对浓度 |
| DOI： |
| 分类号:X592 |
| 基金项目:国家自然科学基金项目（面上项目，重点项目，重大项目） |
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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 |
