库区坡面植被水土保持生态建设模式

The Ecosystem Development Mode of Slope Vegetation for Water and Soil Conservancy in Three Gorges Region

通过对坡面产沙、植被水土保持机理以及库区坡面植被水土保持生态建设模式的研究,结果表明:减小水流拖拽力、水流上举力以及增大土壤的黏聚力都有利于水土保持;植被冠层及枝干的水土保持作用主要体现在植被冠层的水分截留、削弱降雨的溅蚀功能以及抑制地表径流等几个方面;而根系的水土保持作用主要体现在菌根及分泌物能降低土层重度、增加土层的黏聚力,根系能增加土体的有效孔隙度、改善土体的渗透性能。库区坡面有效的水土保持栽植模式应该是:在坡顶,以封山育林为主;在坡面,应垄沟结合,辅以坡改梯等配套工程措施,种植附加值较高的经济作物。

After studying the mechanism of slope sediment yield and the principle of using vegetation for water and soil conservancy as well as the application of this ecosystem development mode in Three Gorges region,it comes to following conclusions： it is beneficial for water and soil conservancy to reduce the pulling and unlift forces of flows,or to increase the cohesion of soil;the main effects of canopy and branches are moisture closure,reduction of rain splash-erosion and restraint of surface runoff etc;as to roots,mycorrhiza and secretion can reduce the bulk density and increase the cohesion of soil stratas;the roots could increase effective porosity and improve permeability.So the valid planting mode in Three Gorges region is closed forest on the top of the slopes and to combine ridge and furrow on slope sides,planting economic fores with high-attached value and assisted by engineering measures such as terracing of sloping fields.