Effect Of Forestland Restoration On Soil Erosion And Soil Quality In Granite Red Soil Region

Vegetation restoration plays an important role in controlling soil erosion and improving soil quality.The risk of soil and water loss is high in the red soil hilly region of south China.Although artificial afforestation can reduce soil erosion in this region,the response of runoff and sediment of different young forestland to different rainfall,and the distribution of soil organic carbon and soil aggregates stability on the slope after many years of forestland restoration are not yet clear.Therefore,based on the observation data of runoff plots for many years,this study analyzed the relationship between runoff and sediment and rainfall in young forestland of granite red soil hilly region,compared the soil and water conservation benefits of different young forestland under the same rainfall conditions and discussed the influence of different vegetation types on the distribution of soil organic carbon and soil aggregates stability,in order to reveal the effect of forest vegetation and rainfall on the understory erosion and soil physical and chemical properties.It is expected that the research may serve as a scientific basis for improving soil nutrient and soil structure of forestland on slope in red soil hilly area.The conclusions were as follows:(1)Compared with the bare land and Eucalyptus plot without surface vegetation,the forestland plot with understory cover has stronger effect on reducing runoff and sediment.Moreover,the runoff and soil loss of the forestland plot with grass or cover are far less than those of the bare land and the forest plot without forest cover.Compared with the bare land,the runoff and soil erosion modulus of the Pinus elliottii in different rainfall range decreased by 11.23%?15.95%and 18.25%?31%,respectively.The runoff and soil erosion modulus of Schima superba decreased by 12.41%?19.63%and 19.13%?36.75%,respectively(3)In the runoff plot of forestland,with the deepening of the soil layer on the slope,the content of soil carbon and nitrogen gradually decreased,and the spatial distribution difference on the slope also decreased accordingly,indicating that the forestland was more conducive to the homogenization of soil organic carbon and nitrogen and the accumulation of organic carbon in the deep soil than the grassland.What's more,compared with the wasteland,the forestland with better understory vegetation can increase the homogenization distribution of soil fine particles on the surface of the slope,which was conducive to improving soil fertility and soil quality(4)The MWD of water stable aggregate of Schima superba forestland plot in the forest-grass model was 20.10%,19.58%and 23.20%higher than that in grassland,Eucalyptus and Pinus elliottii plot,respectively;the GMD was 20%,19.54%and 22.23%higher than that in grassland,Eucalyptus and Pinus elliottii plot,respectively.The results showed that the better spatial structure of forest and grass in granite erosion region is conducive to the stability of soil structure.