Study On Ecological Benefit Evaluation Of Soil And Water Conservation In Rocky Desertification Small Watershed

The rocky desertification area has the characteristics of thin soil and poor soil.And the loss and destruction of water and soil resources has turned into an important problem to limit the economic development of Guangxi.The focus of ecological management and evaluation in Guangxi area is to protect the soil resources,analyze the soil nutrient status and evaluate its contribution to the ecological benefits.In this paper,the soil nutrients were analyzed and evaluated at first,and the model is constructed through the establishment of evaluation index system of rocky desertification.By comparing the results of the model evaluation with the actual effect,the results can reflect the importance of soil nutrient index in the evaluation of the ecological benefits.It has great significance to carry out the work of ecological benefits in Guangxi area.The results can also provide scientific reference for the optimization of ecological control measures and ecological environment protection.The main results are as follows:(1)Analysis of nutrients in typical small watershed in rocky desertification area.In this study,we carried out fixed sampling in three typical small watersheds in Guangxi area,through laboratory analysis,4 indexes which can reflect the characteristics of soil nutrient are selected.The overall level of each nutrient index is calculated under different governance measures.As well as their characteristics of watersheds and slope scale have been discussed and analyzed.At the same time,the soil conservation benefits of the basin are estimated by the available data.The results showed that the order of soil fertility on the scale of small watershed is Longwoba>Changmo>Zheteng.The ranking of the effects of control measures on soil nutrients is soil and water conservation forest>enclosure forest>slope ladder>security forest.(2)Estimation of ecological benefits value in rocky desertification area.Based on the theory of equivalent factor of ecosystem service value,this paper estimates the value of ecological benefit in the study area by using the data of local grain yield and land use area.The results showed that some of the higher values of ecosystem services were soil formation and conservation,gas regulation and water conservation.Land use types in woodland dominated watershed ecological benefit value is higher,the ecological value of small watershed volume from high to low:the Longwoba,Changmo,Zheteng,are 31 million 300 thousand yuan,24 million 140 thousand yuan,20 million 550 thousand yuan,the results are consistent with the results of soil conservation benefit estimation.During the period of treatment,the rocky desertification land in the study area has been well managed,and the land has been fully utilized.At the same time,the area of grassland and forest land has increased greatly,and the land use degree has been improved.(3)Establishment of evaluation index system of ecological benefit in rocky desertification area.This study is based on field investigation and historical data integration,and each indicator in each principal component is analyzed,through the PCA dimension reduction method.Finally,the index system is more comprehensive coverage,and the overlap of the index information is reduced and the representative is stronger.The index system of soil and water conservation effect is formed by 5 reduce rocky desertification and erosion indicators,2 conservation of water source indicators,5 soil improvement indicators,3 ecological stability indicators and 1 flood control and mitigation indicator.The final index system of this study provides a necessary technical support for further discussion on the compensation mechanism of ecological effects and also gives a scientific basis for optimizing the ecological management work in Guangxi rocky desertification region.(4)Construction of ecological benefit evaluation model in rocky desertification area.Based on the initial evaluation index system,combined with subjective and objective factors,using AHP method to determine the weights of model(improved soil erosion reduction layer accounted for 0.4959,accounted for 0.1569,ecological stability layer accounted for 0.1569,accounted for 0.1306,water conservation,mitigation benefits,accounting for 0.0597).The overall ecological benefit evaluation score from high to low in turn is:Longwoba,Changmo,Zheteng.The evaluation results are consistent with the previous value and the actual results.Among them,the evaluation value of the soil conservation benefit is the highest among the categories of the evaluation results,which shows the importance of soil quality in the ecological management of Guangxi rocky desertification area.