Effects of different management measures on soil conservation and the influence of environmental conditions: a case study involving UAV remote sensing on the Loess Plateau

Abstract

To curb further deterioration due to soil erosion, the Chinese government has successively implemented a series of ecological improvement projects across the Loess Plateau (LP). This study used unmanned aerial vehicle remote sensing combined with the revised universal soil loss equation to quantitatively evaluate the soil conservation rate (SR) under 10 management measures and further incorporated the topographic slope into the analysis to describe the impacts of terrain changes. The results showed that the average SR of plots under artificial management measures was 61.24 ± 0.004% (P < 0.01), whereas that under non-artificial measures was 47.90 ± 0.007% (P < 0.01), which showed that human activities on the LP beneficially improved the SR. In addition, benefiting from the Grain to Green Project, cultivated fields, and economic forests exist only in areas with gentle slopes, and both these areas experience almost no threat of soil loss. A terraced structure exerts an obvious effect on extremely steep slopes (>40°), and a greater slope is associated with a more evident effect. However, the risk of structural failure also increases. In addition, due to restricted water conditions, the effects of existing soil and water conservation measures that use tree planting as the main method have the characteristics of horizontal and vertical zonation differentiation. Valley bottom and semi-humid areas are more profitable, and other areas are more suitable for planting drought-tolerant shrubs. In addition to guiding the deployment of future soil and water conservation measures, this study can provide a theoretical basis for adjusting the existing low-efficiency measures.