Temporal-Spatial Variation Characteristics of Soil Erosion in the Pisha Sandstone Area, Loess Plateau, China

Soil erosion in the Pisha sandstone area of the Loess Plateau in China has become a severe environment issue that has raised concerns globally. The projects of ecological restoration in this area and their impact on soil erosion have been analyzed using the unmanned aerial vehicle remote sensing system (UAVRSS) and the revised universal soil loss equation (RUSLE) in the Two-Tiger Valley Basin in 2013 and 2015. Our findings show that: 1) The volume of soil erosion and average soil erosion modulus decreased from 126.24 t year(-1) and 6465.295 t km(-2) year(-1) to 114.7 t year(-1) and 6333.19 t km(-2) year(-1) between 2013 and 2015, respectively. 2) Spatial-temporal variations of soil erosion are extremely significant. All erosion grades recorded different degrees of decline across the study period, except for the level of severe erosion. 3) There is a significant positive correlation between slope degree and soil erosion. When the slope degree was <5 degrees, the soil erosion modulus was 51.355 t km(-2) year(-1), accounting for only 0.87 % of total erosion in this area. When the slope degree was >35 degrees, the soil erosion modulus attained 2574.413 t km(-2) year(-1), and the erosion amount accounted for 43.52% of total erosion. Although anti-erosion and the promotion of plant growth measures have achieved noticeable ecological benefits, the present situation of preventing and controlling soil and water loss is still severe.