三峡库区秭归县退耕还林工程水土保持效益研究

 为揭示退耕还林工程实施后对环境的改善程度,促进我国退耕还林工程的可持续发展,以三峡库区秭归县退耕还林工程为例,在野外调查和定位观测的基础上,对秭归县8种主要退耕还林模式的水土保持效益进行定量分析,并在不考虑土壤类型和坡度变化的前提下,对全县2000年退耕还林地的水土保持效益进行评估。结果表明:1)退耕还林对遏制水土流失有明显的作用,与坡耕地相比,退耕还林后地表径流量平均减少75.25%～85.21%,土壤侵蚀量减少1676.08～1876.66t/（km2.a）,减少幅度为85.4%～95.6%;2)退耕还林工程每年防止土壤流失量为5.49万t,减少河流泥沙淤积量为1.27万t,减少土壤中有机质和全N、全P、全K流失量分别为652、32、82和871t。

Effects of soil and water conservation of the conversion of farmland to forest in Zigui County of the Three Gorges Reservoir Region

To show the effect to implementation to the environment improvement,and promote the sustainable development of the project of conversion of farmland,taking the project of Zigui as an example,the effects of soil and water conservation of the project was analysed,based on the investigation in the field and observation on located experimental plots.The result showed: 1) the effect is visible to control soil erosion,the surface runoff of the forest land was reduced from 75.25%-85.21%,and the soil erosion reduced 85.4%-95.6% comparing with the farmland every year;2) the project reduced soil erosion 54 900 t per year,and reduced the amount of sediment of river 12 700 t,and the loss amount of soil organic matter,N,P,K decreased 652 t,32 t,82 t and 871 t respectively.