Figure 6. Classification
statistics of soil erosion area of LULC in Jiuyuangou watershed in 2010,
2015, and 2020.
We considered the conversion of cropland to other land use types in the
land use space transfer as ‘gain’, and the conversion of other land use
types to cropland as ‘loss’. For changes in the spatial pattern of soil
erosion, we considered the increase in soil erosion grade as ‘loss’, and
the decrease in soil erosion grade as ‘gain’. Therefore, we plotted a
bivariate choropleth map (Figure 7) to understand spatial patterns and
the association between gain, loss, and no change in soil erosion and
LULCC. During the study period, some areas of the watershed were covered
by ‘no change’ between LULCC and soil erosion change, mainly
concentrated near roads, residential areas, cultivated land, and
perennial forest land in the eastern part of the watershed.
Significantly, the northeast of the watershed showed a common ‘loss’
between soil erosion change and LULCC, and cropland near residential
areas in the central and southwest of the watershed showed a common
‘gain’ between soil erosion change and LULCC. At the same time, we also
observed a ‘gain’ in soil erosion change with ‘no change’ in LULCC in
the central and southwestern watersheds. In addition, the soil erosion
level in the central and southwest part of the watershed declined, and
the land use pattern followed a trend of transforming cropland into
forest and grassland. Therefore, ‘gain’ was detected for both LULCC and
soil erosion change in the central and southwest part of the watershed,
with a high spatial correlation between LULCC and soil erosion change.