The influence of planting Carex praeclara and Leymus secalinus on soil properties and microbial community in a Zoige desertified alpine grassland

Abstract

Grassland degradation has seriously affected the stability and sustainable development of local ecosystem in Zoige. Carex praeclara and Leymus secalinus can grow on severely desertified soil, while previous research is scarce on the restoration of the sandy soil by planting them in phytoremediation. In this study, we analyzed the effects of planting C. praeclara and L. secalinus on soil physicochemical properties, microbial community and functional composition within the rhizosphere. Compared with the bare soil, planting C. praeclara and L. secalinus significantly increased soil fertility, including available potassium, available phosphorus, total nitrogen and organic carbon, but lowered soil pH in the rhizosphere. Metagenomic analysis showed that the microbiota composition demonstrated great variations between the rhizosphere and bare soil samples, with predominant taxa including Actinobacteria, Proteobacteria, Acidobacteria and Chloroflexi in all the samples. Genes being over-abundant included those implicated within nutrient acquisition, stress response, transposable element and plant growth promotion, suggesting interplays across microbes / plants and microbes /microbes are stronger within rhizosphere soil. Relative expression for key genes participating within microbial nitrogen (N) and phosphorus (P) transforming process were elevated within the rhizosphere, in comparison to bare soil, suggesting possible enhancing of soil N- and P-cycling potential within rhizosphere soil. In conclusion, planting C. praeclara and L. secalinus increased soil fertility, changed the structural and functional composition and enhanced N- and P-cycling potential of soil microbial communities, and thus benefited the restoration of desertified soil in alpine grassland.