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| Effects of contour hedgerow on soil physical properties in the Three gorges reservoir area |
| Cheng Dongbing,Li Zhaoxia,Cai Chongfa,Peng Yanping |
| College of Resource and Environment,Huazhong Agricultural University,430070,Wuhan,China |
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Abstract Contour hedgerow is a very common and effective technique around the world,which is employed to revegetate on cultivated slope land and conserve water and soil resources.Contour hedgerow is considered an effective way of sustainable development of agroecosystem in the Three gorges reservoir area.Alluvial soils in front of hedges(Leucaena leucocephala and Vitex negundo) were taken as the objects,to evaluate the effects on soil water and physical properties from different distances to hedgerows(ridge) at different soil depths by contour hedgerow agriculture compound planting on slope land.The results showed that non-capillary porosity of soil,saturated hydraulic conductivity,saturated water content and natural water content in the hedgerows treatments were higher than in the rocky ridge terrace treatment,while the soil bulk density and field capacity in the hedgerows treatments were lower than in the rocky ridge terrace treatment,which reflected that the effects on water and soil conservation by hedgerows are significant,especially in the top and second layer.Based on the same depth, with the extending of the distance to hedgerows(ridge),in the hedgerows treatments soil bulk density and natural water content increased gradually,and noncapillary porosity of soil,saturated hydraulic conductivity and saturated water content decreased gradually,while no apparent change in the rocky ridge terrace treatment.With the deepening of the soil layer,in each treatment soil bulk density and natural water content increased gradually,and non-capillary porosity of soil,saturated hydraulic conductivity and saturated water content decreased gradually accordingly,and their differences among treatments were also lessened gradually.The distance to hedgerow(ridge) reflected the degree of effects on soil water and physical properties by hedgerow indirectly.The closer to hedgerow is,the greater the effects are.Comparing treatments of Leucaena leucocephala and Vitex negundo,their effects were equivalent.
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Received: 26 September 2007
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