4 Discussion
Based on analysis of microbial biomass C and N in H. rhamnoidespure forest (shady slope), H. rhamnoides pure forest (sunny
slope), H. rhamnoides and Chinese arborvitae mixed forest, andH. rhamnoides and Pinus tabulaeformis mixed forest, we
examined the driving capacity of the soil carbon (C) cycle and the
mineralization and fixation of soil microorganisms on nitrogen (N). The
soil microbial C and N analysis showed that soil microbial biomass N and
N in different forest layers exhibited a trend of a small change with
increasing soil layers; that is, as the soil depth increased, the soil
microbial activity weakened gradually. A one-way ANOVA analysis of the
soil microbial community showed that the difference in the soil
microbial communities among different forests in the study area was
smaller than was that in different soil layers. Gracilibacteria,
Gemmatimonadetes, Nitrospirae, Parcubacteria, and Actinobacteria are
highly correlated with most of the soil environmental factors, and
Ichthyosporea and Ciliophora in fungi are correlated strongly with most
of the environmental factors and are affected greatly by them. Compared
with the bacterial community, the Pearson correlation between the fungal
community and soil environmental factors is lower; that is,
environmental factors have a greater effect on bacteria than on fungi.
Conversely, the study found more species of bacteria than of fungi in
the soil under the H. rhamnoides forest, which may be why there
are more bacteria in the bacterial community that are significantly
related to environmental factors.
Restoration mainly affects the quantity and community of soil
microorganisms by affecting the litter, root morphology and secretion,
and the material and energy transformation process in the whole
ecosystem. To better analyze the mechanism of influence of vegetation on
microorganisms and the influence of site conditions and environmental
factors on soil microbial community diversity, the litter and root
exudates under various H. rhamnoides forests can be studied
further.
This study only addressed the soil microbial characteristics of H
rhamnoides forest in the process of revegetation in Wuqi, Shaanxi
Province. To better analyze the microbial characteristics of H.
rhamnoides forest under the effect of revegetation in the Loess
Plateau, similar studies can be conducted in other areas of the Loess
Plateau. The results of these experiments can be analyzed to better
explore the soil under H. rhamnoides forest in the process of
vegetation diversity of soil microbial community and is expected to
provide some data supporting the study of revegetation in the Loess
Plateau.