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| Modeling Spatial and Temporal Variation of Nitrate Loss via Interflow in a Sloping Field of Purple Soil |
| Received:April 23, 2015 |
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| KeyWord:purple soil;fertilization method;nitrate leaching;numerical simulation |
| Author Name | Affiliation | | LONG Tian-yu | Key Laboratory of Eco-Environment of Three Gorges Region of Ministry of Education, Chongqing University, Chongqing 400045, China
National Centre for International Research of Low-carbon and Green Buildings, Chongqing University, Chongqing 400045, China | | LIU Xiang-zhang | Key Laboratory of Eco-Environment of Three Gorges Region of Ministry of Education, Chongqing University, Chongqing 400045, China | | LIU Jia | Key Laboratory of Eco-Environment of Three Gorges Region of Ministry of Education, Chongqing University, Chongqing 400045, China
National Centre for International Research of Low-carbon and Green Buildings, Chongqing University, Chongqing 400045, China |
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| Abstract: |
| A two-dimension convection-dispersion model was established to simulate the transport of nitrate in cultivated and non-cultivated layers in a sloping cropland of purple soil under broadcast incorporated and hole fertilization. Water transport in purple soil could be divided into saturation stage and interflow stage, and the interflow occurred during the middle and later period of rainfall when the soil was saturated. During the early period of rainfall, the loss of nitrate nitrogen was via downward infiltration under broadcast incorporated fertilization, while it was through diffusion from the holes under hole fertilization. During the later period of rainfall, however, losses of nitrate nitrogen were mainly via subsurface flow under both fertilization methods, with faster nitrate leaching in cultivated layer than in non-cultivated layer. At the same amount of fertilizer(150 kg·hm-2), soil nitrate nitrogen concentrations were 0.110~0.160 kg·m-3 under broadcast incorporated fertilization, but were 0.040~0.120 kg·m-3 under hole fertilization, at the end of raining. The present results indicate that cumulative nitrate nitrogen losses are greater under hole fertilization than under broadcast incorporated fertilization. |
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