Soil And Water Conservation Ecological Benefits Of Different Treatment Measures In The Red Soil Region Of Northern Jiangxi

Jiangxi is the central region of the red soil in China.Due to the influence of natural and human factors,serious soil erosion occurred in the area and a vicious circle of ecological environment emerged.In response to this environmental problem,Chinese scholars have put forward many prevention and control measures,the comprehensive treatment of small watersheds as a unit is a very effective measure to control soil and water erosion and improve the ecological environment in recent years.This study selected the Changling small watershed in Xingzi County as the study area.Through cell data monitoring,on-site investigation and indoor experiments,analyze the benefits of runoff and sediment reduction and improving soil environmental quality compared with the four measures of Camellia oleifera,Taxus chinensis,Soil conservation forest,and Closed forest in the basin.Finally,using entropy weight synthesis method to compare and analyze the ecological benefit scores of different treatment measures.Conclusions are as follows.(1)Through the observation data of the community in 2016-2017,the amount of sediment and runoff for different treatment measures is approximately the same as the rainfall during the year.Seasonal scale mainly distributed in spring and summer.On the monthly scale,the rainy season is mainly distributed during March-September.Compared with the control grounds,the efficiency of runoff and sediment reduction has been improved in all governance measures.And the benefits of reducing flow are all lower than those of sediment reduction.The efficiency of runoff and sediment reduction between different treatment measures are as follows: Closed forest>Taxus chinensis>Soil conservation forest>Camellia oleifera>Leisurely.(2)Compared with the control,these four measures can improve the physical and chemical properties of the soil in general,and the effects of the measures on soil physical and chemical properties in different soil layers are different(p<0.05).The soil moisture content,grain composition,bulk density,and pH value in different physical and chemical indicators of different soil layers increase as soil depth deepens,and the change of porosity is the opposite.There is no obvious regularity in the change of soil water holding capacity and temperature with soil depth.The physical and chemical properties of soil with different types of measures vary with the change of slope position.Soil moisture content,bulk density and porosity are the highest under the slope,the temperature is the higher on the slope,and the pH value is higher in the slope.(3)Compared with the control,the four measures increased the average content of soil available nutrients in the 0-40 cm soil layer.However,according to the standard of soil nutrient classification,the soil nutrient contents of these measures are all in the middle and low level,and lack of soil nutrients.The measures for Soil conservation forest between organic matter and available phosphorus content increased significantly(p<0.05),And Taxus significantly increased the available nitrogen and available potassium(p<0.05).In the different soil layers,the soil surface nutrient content is higher than the subsurface soil.From the scale of the whole sampling area,it is known that the soil nutrient average content change trend is higher on the slope and in the middle of the slope than the slope down,but the soil nutrients with different treatment measures do not change significantly with slope position.(4)Compared with the control,these four measures can increase the ability of the soil to resist the erosion of the external forces and reduce the K value of soil erodibility,and the K value of 0-20 cm soil layer is less than 20-40 cm soil layer.Different soil layers have different rules for the distribution of soil K values,and the overall Closed forest is more resistant to soil erosion.Compared with the control,all the control measures can effectively improve the quality of the soil.(5)Compared with the control,these four measures can all improve the soil quality grade of 0-40 cm soil layer,among which Taxus chinensis has the best improvement effect on soil quality,and the soil quality is higher(Grade II),followed by banned forest and water conservation.Lin and Camellia,the soil quality is moderate(Grade III).In different soil layers,the soil quality improvement effect of each measure on 20-40 cm soil layer was higher than 0-20 cm soil layer as a whole.(6)Comprehensive evaluation of eco-efficiency of soil and water conservation under the five different measures of Camellia oleifera,Taxus chinensis,Closed forest,Soil conservation forest and Leisurely in changling small watershed using entropy weight comprehensive index method.The order of the composite index is: Closed forest>Soil conservation forest>Taxus chinensis>Camellia oleifera>Leisurely.The overall performance is that the ecological benefits of Closed forest and Soil conservation forest are better,and the ecological benefits of economic forests are slightly lower.This shows that in the stage of ecological benefits,the implementation of banned measures and the planting of Soil conservation forest are ideal management methods.