Vertical distribution characteristics of soil bacterial community
structure during vegetation restoration in red soil erosion area
Abstract
The vertical distribution of soil microorganisms in soil indicates the
restoration degree of degraded soil ecosystems. We took the untreated
bare land and vegetation restoration sample plot in the red soil erosion
area of southern China as the object of study; comparatively analysed
the soil bacterial community changes in the 0 to 10, 10 to 20, 20 to 30
and 30 to 40 cm soil layers; and explored the environmental factors
driving the change in the soil bacterial community. The poor nutrient
conditions created by soil erosion increased the competitiveness of
autotrophs and made Chloroflexi the dominant phylum of bacteria.
Soil erosion led to the gradual similarity of soil bacterial communities
in the 0 to 10, 10 to 20 and 20 to 30 cm soil layers. However, only the
relative abundance of Actinobacteria changed in different soil
layers in the erosion area, mainly due to the inconsistent distribution
of soil organic carbon caused by erosion affecting the change in the
Actinobacteria relative abundance in the soil layer. After
vegetation restoration, the soil properties of the eroded land were
obviously improved, and the dominant bacterial phylum changed from
autotrophic bacteria ( Chloroflexi) to heterotrophic bacteria (
Actinobacteria). The change in community structure existed only
in the 0 to 30 cm soil layer in the restoration area, while the
community structure changed to mainly Proteobacteria in the 30 to
40 cm soil layer. The change in the respective proportions of
Chloroflexi, Proteobacteria and Actinobacteria was
the main reason for the difference in soil bacterial community structure
among soil layers. The change in soil aggregates caused by vegetation
restoration was the main environmental factor driving the variation in
soil bacterial community structure, and the formation of aggregates was
closely related to soil organic carbon. The vertical distribution of
Actinobacteria in different soil layers can indicate the degree
of soil ecosystem restoration in the red soil erosion area of southern
China, and the relationship between Actinobacteria and soil
organic carbon was significant.