Effects of Soil and Water Conservation Measures on Runoff and Sediment Yield in Red Soil Slope Farmland under Natural Rainfall

Xiaoan Chen,Ziwei Liang,Zhanyu Zhang,Long Zhang

doi:10.3390/su12083417

Xiaoan Chen, Ziwei Liang + Show 2 more

Open Access

https://doi.org/10.3390/su12083417

Copy DOI

Abstract

This paper analyzes the relationship between runoff, soil erosion, sediment particles, and natural rainfall characteristics on sloping farmland in the red soil region of southern China. The surface runoff and soil loss data were measured on runoff plots during 66 natural rainfall events from 2015 to 2018 in Jiangxi Province. The results show that the maximum 30-min rainfall intensity (I30) is positively related to the runoff depth, soil erosion modulus, and sediment mean weight diameter (MWD). With the increase in I30 during rainfall, the coarse sand content increases, and the fine sand content decreases. The average annual runoff of slope tillage, hedgerows with slope tillage, straw mulching with conventional tillage, and contour tillage decreased by 32.56%, 65.87%, 83.99%, and 87.30%, respectively, compared with that of bare land. Soil and water conservation measures can significantly reduce slope runoff. The flow-reduction effect of contour tillage and straw mulching with conventional tillage increases as I30 increases, and the flow-reduction effect of hedgerows with slope tillage first increases and then decreases as I30 increases. The coefficients of variation and standard deviations of the flow-reduction effects of different soil and water conservation measures decrease with increasing I30. The average annual soil erosion moduli of slope tillage, hedgerows with slope tillage, contour tillage, and straw mulching with conventional tillage decreased by 59.33%, 91.29%, 97.17%, and 98.45%, respectively, compared with that of bare land. Soil and water conservation measures can significantly reduce the sediment yield on slopes. The flow-reduction effects of hedgerows with slope tillage, contour tillage, and straw mulching with conventional tillage all increase with I30, and their coefficients of variation and standard deviations decrease with I30. The average single rainfall erosion sediment MWD of decreased by 5.91%, 8.33%, 9.69%, and 13.32%, respectively, compared with that of bare land. Straw mulching with conventional tillage can significantly reduce the MWD of erosion sediment, effectively reduce the content of coarse sand, and increase the content of fine sand. Straw mulching with conventional tillage is a very good soil and water conservation measure for sloping farmland. It not only has the best effect on reducing flow and sediment, but also can effectively intercept coarse sand and reduce the MWD of erosion sediment.

Highlights

Accelerated soil erosion has been an enduring problem since agriculture began, and is considered one of the major threats to soil ecosystem services [1,2]
We investigated surface runoff and soil loss during rainfall events from 2015 to 2018, using five measures in the red soil region
It can be seen that the rainfall characteristic indicators are the maximum 5-min rain intensity I5, the maximum 10-min rain intensity I10, the maximum 30-min rain intensity I30, and the maximum 60-min rain intensity I60, which are significantly related to the depth of the secondary rainfall runoff and the soil loss Ms This indicates that the maximum period rain intensity is the key rainfall characteristic value that affects the sloping farmland runoff and sand production

Summary

Introduction

Accelerated soil erosion has been an enduring problem since agriculture began, and is considered one of the major threats to soil ecosystem services [1,2]. Soil erosion is a serious problem in a variety of climatic areas, but especially in the semi-arid and semi-humid areas of the world [3], such as Europe [4], central Asia [5], and China [6]. Red soil is a kind of soil developed in subtropical dry and wet seasons, with distinct areas and well-drained terrain. This soil can form from iron-rich sediments or the compounds may develop in the soil as it weathers; it contains more iron and aluminum oxides, and has a coarse texture, low fertility, and strong acidity. The sloping croplands are the main source of a large amount of the sediment in rivers, accounting for 6.7% of the total soil erosion in the country [12]. Rainfall on the slope causes rain and runoff to destroy the soil structure, resulting in the separation, handling, and deposition of soil particles [13]

Objectives

Results

Conclusion