[Effects of Reseeding and Fertilization on Bacterial Communities in Rhizosphere Soil of Alpine Degraded Grassland]

Abstract

Reseeding and fertilization are common ecological restoration measures in the Qinghai-Tibet Plateau Region for degraded grasslands, yet their impacts on rhizospheric bacterial communities remain unclear. This study utilized high-throughput sequencing technology to systematically investigate the characteristics of rhizospheric soil bacterial communities in degraded high-altitude grasslands managed with reseeding and fertilization. The results indicated a significant decrease in the Shannon and Simpson indices with fertilization treatment, while the reseeding + fertilization treatment exhibited the most pronounced impact on community structure. Actinomycetota, Pseudomonadota, and Acidobacteriota were the dominant phyla in the rhizosphere bacterial community. There was a decrease in network complexity and an increase in stability within bacterial communities with the reseeding, fertilization, and fertilization + reseeding treatments. The networks were predominantly characterized by positive correlations after fertilization, reseeding, and fertilization + reseeding treatments, involving key species like Pseudomonadota, Actinomycetota, and Acidobacteriota. Mantel tests revealed that soil total nitrogen （TN）, total phosphorus （TP）, available potassium （AK）, and nitrate nitrogen （NO₃^--N） were the key environmental factors in driving bacterial community composition. The study of the rhizosphere soil bacterial community in alpine degraded grassland can provide a theoretical basis for tailored management strategies in the restoration of degraded high-altitude grasslands and lays a scientific foundation for their conservation.

Keywords: degraded alpine grasslands; fertilization; molecular ecological networks; reseeding; rhizospheric bacterial community.