| 不同植被覆盖度对流域氮素径流流失的影响 |
| 摘要点击 3183 全文点击 3554 投稿时间：1999-12-21 |
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| 中文关键词 小流域模型 植被覆盖度 氮素流失 |
| 英文关键词 catchment model vegetation coverage nitrogen loss |
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| 中文摘要 |
| 以 8.27km2 纸坊沟流域 1∶400比例模型为研究对象 ,在人工控制条件下 ,模拟天然降雨 (降雨强度 2 mm/min,历时30 min) ,研究不同植被覆盖度对流域氮素流失的影响 ,揭示小流域土壤氮素随径流流失规律 .研究表明 :当流域植被覆盖度分别为 60%、40%、20%和 0%时 ,土壤铵态氮流失量分别为 87.08、44.31、25.16和 13.71 kg/ km2 ;硝态氮流失量分别为 85.50、74.05、63.95和 56.23kg/km2;而流域有机质流失量为 15.67、24.02、44.68和 164.87;全氮流失量为 0.81、1.18、1.98和7.51t/ km2.产流过程中径流及泥沙中氮素含量随产流时间的延长呈下降趋势 ,而流失累积量呈逐渐增大趋势 .植被覆盖虽能有效地减少土壤侵蚀和全氮的流失 ,却能增加土壤矿质氮的流失 . |
| 英文摘要 |
| The Zhifang gully catchment,which model was established by 1∶400 scales,has area of 8.27km2.Under controlling artificially rainfall with intensity of 2mm/min and lasting 30min,the soil erosion and N loss of catchment model was studied for revealing the catchment N loss in runoff and sediment as effected by vegetation coverage.The results show that loss amounts of runoff ammonium and nitrate were 87.08,44.31,25.16,13.71kg/km2 and 85.50,74.05,63.95,56.23kg/km2 respectively in vegetation cover ratios of 60%,40%,20% and 0%.The loss amounts of sediment organic matter and total N were 15.67,24.02,44.68,164.87t/km2 and 0.18,1.18,1.98,7.51t/km2 respectively.With delay of runoff-yield time,the nitrogen concentrations in runoff and sediment drop off,whereas,the accumulation amounts of nitrogen loss rise gradually.Vegetable cover on soil is an available method to control soil erosion and total N loss,nevertheless,it might enhance soil mineral nitrogen loss. |
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