Distinct bacterial community compositions in the Populus rhizosphere under three types of organic matter input across different soil types

Organic matter addition is an important management practice for maintaining soil fertility and the sustainability of artificial ecosystems. However, the effects of different types of organic matter on the microbial community in the perennial plant rhizosphere are not well understood. A pot experiment was conducted to study how soil type and organic inputs influence bacterial community composition in the Populus rhizosphere. Plants were grown in the common forest soil (COM) and the poplar forest soil (POP), and three types of organic matter were applied. The rhizosphere soils were sampled after four months growth and rhizobacterial community was analyzed by 16S rRNA high-throughput sequencing. Organic inputs increased the alpha diversity in COM but not in POP. Both the soil type and organic inputs significantly influenced community structures. The different types of organic matter jointly enriched Ramlibacter, Sphingomonas and Adhaeribacter OTUs in the Populus rhizosphere. Amendment with organic matter improved network complexity and stability but had little effect on the species composition of the rhizosphere network at the phylum level. Increased network stability was found in the Populus rhizosphere with organic amendments. These results highlight that organic matter input increased the diversity and network interactions in the Populus rhizosphere, indicated promoting species coexistence caused by resource availability improvement.