| As a typical southern red soil erosion area of China,Changting County,Fujian Province has a long history and rich experience in soil and water conservation,and is a model of soil erosion control in the southern red soil erosion area of China.In the long-term management process in this region,different types of management measures have been summarized such as contour grass irrigation,replanting of broad-leaved forests,and grass planting in small holes,and so on.All of them have achieved good results,but the mechanism and effects were short of long-term positioning data support,and to some extent,the promotion of governance measures is limited.Therefore,this study takes Hetian Town’s intensity erosion control area as the research area,and selects different control measures with similar background for the past 2-3 years,10 years,and 30 years as typical sample areas,takes no governance plot and Fengahuilin(Local top communities)as a control to study the impact of different management measures on soil structure and physical and chemical properties.Simultaneously,observe the characteristics and laws of runoff and sediment changes with rainfall under different control measures,and discuss the runoff and sediment characteristics of the control measures of contour grass irrigation belt,replanting broad-leaved forest,replanting broad-leaved forest + small strip ditch sowing grass and small hole sowing grass.The aim of this research is that provide basic data and scientific basis for the comprehensive management of the eroded slopes of red soil in the south.main conclusion:(1)By analyzing the effects of different control measures on the physical and chemical properties of the soil,the results show that the four measures of contour grass irrigation belt(horizontal strip ditch preparation),replanting broad-leaved trees,replanting broad-leaved trees+ small strip ditch sowing grass and small hole sowing grass can improve the physical and chemical properties of the soil to a certain extent and effectively control soil degradation.However,the restoration of soil texture and soil layer structure is a long-term and long process.It takes many years of efforts to achieve the goals of controlling soil erosion,improving soil,and restoring biodiversity.(2)From the perspective of the changes in runoff and sediment yield of various measures in different years,the four control measures all have certain functions to maintain soil and water.The contour grass irrigation belt uses grass,irrigation and a combination of trees to produce less runoff and sediment in the community,and its control effect is the best;replanting broad-leaved forest + small strip ditch sowing grass and small hole sowing grass at the early stage of management,because Herbs have a faster growth rate and a shorter cycle,which can play a role in storing water and retaining sand faster;while replanting broad-leaved forest is not effective in the early stage of management,but this measure can also produce good water and sand retention in the later stage of management.(3)From the perspective of runoff and sediment characteristics of different measures under different rain intensities,in the early stage of each mode of governance,light rain intensity rainfall will produce a small amount of surface runoff.When the rainfall reaches more than 8 mm,each community will produce a small amount of soil erosion.It was found that the runoff and sediment yield of the small hole sowing plot was relatively small for moderate rain and below rainfall intensity,and the water retention and soil fixing function was relatively better when the heavy rain and above intensity were the contour grass irrigation zone;after 3 years of treatment,except outside the untreated area,each treatment measure area will not cause significant soil erosion below the moderate rain intensity,and the correlation between rain intensity and runoff and sediment yield will be significantly reduced. |
