Analysis of temporal and spatial changes of soil erosion under LULCC
based on CSLE in the typical watershed on the Loess Plateau
Abstract
Extreme meteorological events occur frequently, and changes in the
spatial pattern of land use have greatly affected the soil erosion
process in the hilly and gully region of the Loess Plateau. As a typical
governance watershed in the hilly and gully area of the Loess Plateau,
the Jiuyuangou watershed has experienced significant changes in land use
and land cover (LULCC) in the past ten years due to the conversion of
farmland to forests, economic construction, and abandonment of
cultivated land. However, the evolution process of soil erosion under
LULCC in the watershed is unclear. This study uses satellite images to
extract information on LULCC in the watershed and the Chinese soil loss
equation (CSLE) model to evaluate the temporal and spatial evolution of
soil erosion in the watershed from 2010 to 2020. The main results showed
that: (1) The continuous vegetation restoration project in the watershed
reduced soil erosion from 2010 to 2015; however, the frequency of
extreme rainfall events after 2015 reduced its impact. The annual
average soil erosion modulus decreased from 10.85 t ha
–1 yr –1 in 2010 to 8.03 t ha
–1 yr –1 in 2015, but then
increased to 10.57 t ha –1 yr –1in
2020; (2) The main LULC type in the Jiuyuangou watershed is grassland,
accounting for 62.23% of the total area of the watershed, followed by
forest land (28.41%), cropland (6.77%), building (2.49%), and water
(0.09%). The multi-year average soil erosion modulus for land use type
is cropland > grassland > building
> forest land; (3) Significant spatial correlations between
soil erosion change and LULCC for common ‘no change’ and common ‘gain’
occurred in the settlements, roads, valleys, and areas near the human
influences with good soil and water conservation, but not other regions
due to the influence of climatic factors (heavy rain events). This study
provides a scientific reference for planning and managing water and soil
conservation and ecological environment construction in the basin.