Examining Soil Erosion Responses to Grassland Conversation Policy in Three-River Headwaters, China

Yuting Zhao,Huilong Lin,Yanfei Pu,Rong Tang

doi:10.3390/su13052702

Yuting Zhao, Huilong Lin + Show 2 more

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https://doi.org/10.3390/su13052702

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Abstract

Soil erosion in the Three-River Headwaters (TRH) region has continued to intensify in recent decades due to human activities and climate change. To reverse this situation, the Chinese central government has launched the Subsidy and Incentive System for Grassland Conservation (SISGC). As a sign of the effectiveness of SISGC implementation, the dynamic changes of soil erosion can provide timely feedback for decision makers and managers. The Revised Universal Soil Loss Equation (RUSLE) model was used to simulate the spatial distribution of soil erosion before and after SISGC implementation, and Mann–Kendall (MK) test to reveal the effect of policy implementation. The results showed that: (1) the soil erosion in the TRH was mainly mild (83.83% of the total eroded area), and the average soil erosion rate and the total erosion were 13.63 t ha−1 y−1 and 323.58 × 106 t y−1 respectively before SISGC implementation; (2) SISGC implementation has curbed soil erosion. After SISGC implementation, the total soil erosion decreased by 3.80%, which showed obvious differences between grassland types; (3) The influences of SISGC were mainly because it has increased vegetation cover, further decreasing soil erosion. However, soil erosion in Alpine grassland has deteriorated, indicating direct targeted policymaking should be on the agenda. Furthermore, SISGC should be continued and grassland-type-oriented to restore the grassland ecosystem.

Highlights

Soil erosion is a complex process, affected by the interaction of multiple factors such as rainfall erosivity, soil texture, slope, vegetation coverage, freezing and thawing, human activity, etc. [1,2], and these factors generally have obvious spatial differences [3]
The Revised Universal Soil Loss Equation (RUSLE) model is a linear equation to quantify soil erosion according to the followThe RUSLE model is a linear equation to quantify soil erosion according to the ing equation [13,48]: following equation [13,48]: A = R × K × LS × C × P
As for grassland types, the amount of soil erosion in Alpine meadow increased by 0.12%, while in other types they declined

Summary

Introduction

Soil erosion is a complex process, affected by the interaction of multiple factors such as rainfall erosivity, soil texture, slope, vegetation coverage, freezing and thawing, human activity, etc. [1,2], and these factors generally have obvious spatial differences [3]. Soil erosion studies generally use the runoff plot method, isotope tracer method, and model simulation [4,5,6]. The runoff plot method and isotope tracing method are suitable for small-scale research such as patch scale and slope scale [2], but are inefficient and expensive for large-scale quantitative research. The use of modeling is a critical mothed to assess soil erosion. Several models have been developed around the world for the assessment of water erosion, ranging from physical model and empirical model. The physical models include the Water Erosion Prediction Project (WEPP) [7,8], The European Soil Erosion Model (EUROSEM) [9,10], the Limburg Soil Erosion Model (LISEM) [11], and the Soil Erosion

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