Microbial diversity in rhizosphere soil of soybean grass under different cultivation methods in an alpine region
Abstract Background A large number of studies have shown that soybean grass with mixed seeding cultivation can significantly improve the yield and quality of forage grass compared with clean culture cultivation.This study explores the differences in the characteristics of the composition and diversity of the microbial community in the rhizosphere of soybean grasses between clean culture and mixed seeding methods in an alpine region. We used high-throughput sequencing technology to determine the microbial diversity and analytical methods to determine the physicochemical characteristics of plant rhizosphere soil of Avena sativa L. and Vicia sativa L. Results There were no significant differences in pH, total nitrogen, total phosphorus, and total potassium in the rhizosphere soil samples of soybean grasses under the clean culture and mixed seeding methods, while there were significant differences in the available nitrogen, available phosphorus, available potassium, and organic matter content (P < 0.05). The bacterial diversity of the rhizosphere soil of Avena sativa L. was the highest under the clean culture method, and the fungal diversity of the rhizosphere soil of Vicia sativa L. was the highest under the clean culture method. Furthermore, the microbial diversity of the rhizosphere was significantly different under the different cultivation methods (P < 0.05). The differences between the microbial species in the rhizosphere of the treated soil were at three class level. The abundance of Alphaproteobacteria and Actinobacteria in the rhizosphere of Avena sativa L. and Vicia sativa L. under the mixed seeding method was conspicuously higher than that of Avena sativa L. and Vicia sativa L. under the clean culture method, while the abundance of Gemmatimonadetes, Nitrospira, and Acidimicrobiia were significantly lower than that obtained under the clean culture method. Regarding fungal predominance, Mortierellomycetes was the most abundant (32.66%) under the mixed seeding method, while the abundance of Sordariomycetes and Leotiomycetes were significantly lower than that under clean culture. The distribution of bacterial and fungal community species in the rhizosphere differed significantly between the treatments. The Kyoto Encyclopedia of Genes and Genomes metabolism analysis showed that the metabolic pathways of functional genes in the soil microbial communities were similar. Conclusions Mixed sowing changed the diversity of plant rhizosphere microbial community structure and promoted plant yield.