Revegetation by reseeding perennial grass has proven to be a highly effective way for restoration of degraded grassland. This process can directly or indirectly impact the biological characteristics of the soil, especially the soil microbes, which has certain functions in regulating many key ecological processes of grassland. A long-term restoration experiment established (since 2014) on degraded sandy grassland to address the soil improvement progress, located in northwestern part of Beijing. Smooth brome (SB) and Medicago sativa (AF) were used as reseeding restoration method (each has 9 plots), and natural recovery site(CK, 9 plots) as control. Plants and soil cores were collected to analysis the vegetation and soil properties, soil samples were taken at 0-10cm, 10-20cm, and 20-30cm depths, all soil microbial communities were characterized by using the Illumina MiSeq standard protocol for DNA sequencing. Soil bacterial and fungal abundance and diversity were calculated based on OTUs.
Results/Conclusions
Our results showed that both soil microbial biomass C and N in revegetation plots increased significantly compared to the natural recovery treat (P<0.05). The OTUs and diversity index of AF and SB showed a significant higher than that of CK at the very second year of the restoration. Soil microbial abundance has a significant positive correlation with litter biomass and SOM. Bacteria and fungi were mainly present in the 0-10cm depths, significantly higher than other layers. We found that the plant species diversity of SB was significantly lower than that of CK and AF (P<0.01), however, there was no distinct similar difference in the diversity of microbial communities was observed, this suggesting that the decreased plant diversity caused by one increasing dominant species such as smooth brome could not be consist with the belowground communities. In contrast, different dominant plant species (SB, AF) could alter the relative abundances of specific bacteria and fungi at phylum level in this research.
Current findings indicate that dynamics of soil microbial communities may differ across revegetated species, ongoing work of soil microbial communities by Q-PCR and PLFA may further explore the response mechanism to revegetation.