| 土地管理措施对营养物质排放的影响 |
| 摘要点击 2056 全文点击 810 投稿时间：2008-12-10 修订日期：2009-02-05 |
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| 中文关键词 非点源污染 等高种植 营养物质 模拟 土地利用 |
| 英文关键词 non-point source pollution contour planting nutrients simulation land use |
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| 中文摘要 |
| 采用分布式的非点源污染模型SWAT（soil and water assessment tool），结合GIS技术，模拟了张家冲小流域化肥施用量变化、等高种植和退耕还林对营养物质氮磷排放的影响.结果表明，当农业用地的氮肥施用量由630 kg/hm2增加到955 kg/hm2，磷肥施用量由200 kg/hm2增加到300 kg/hm2时，氮、磷营养物质排放量也呈现增大的趋势.其中，硝态氮负荷达到了3 776.59 kg，增加了19.7%，变化率最大，变化率最小的为无机磷，仅增加了2.7%.采取等高种植的方式对氮、磷排放负荷的影响较小.当小流域内坡度＞25%的坡耕地全部退耕还林后，各种形态氮、磷排放负荷下降,其中有机态磷下降16.3%;有机氮、氨氮和无机磷与退耕还林前相比，分别降低了22.7%，25.4%和27.9%,在张家冲小流域，对坡度＞25%的坡耕地实行退耕还林、减少化肥施用量对减少氮磷负荷排放作用明显. |
| 英文摘要 |
| The SWAT model, coupled with a GIS, was applied to simulate the effects of fertilizer application, contour planting and returning land for farming to forestry on nutrients discharges. The results showed that when nitrogen fertilizer of agricultural land increased from 630 to 955 kg/hm2, and phosphorus fertilizer increased from 200 to 300 kg/hm2, nitrogen and phosphorus nutrient emissions have shown a growing trend. Nitrate nitrogen loads reached to 3 776.59 kg which increased 19.7% and the rate of changes was the largest. The change rate of inorganic phosphorus was the smallest which increased only 2.7%. The impact of emission loads on nitrogen and phosphorus was the smallest if contour planting was adopted. When slope farmland which slope is greater than 25% all returned land for farming to forestry, the emission loads of various forms of nitrogen and phosphorus decreased, organic phosphorus decreased 16.3% among them. Organic nitrogen, ammonia nitrogen and inorganic phosphorus compared with before returning land for farming to forestry, decreased 22.7%, 25.4% and 27.9% respectively. In small basin of Zhangjiachong, returning farmlands to forests and reducing the amount of chemical fertilizer on the slope farmlands which slopes are larger than 25% have played a prominent role. |
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