Pecan plantation age influences the structures, ecological networks, and functions of soil microbial communities

Abstract Understanding the changes in microbial communities with increasing plantation age will benefit the maintenance of forest health and productivity and the sustainable development of forest ecosystems. It was not clear before this study whether the microbial communities of pecan ( Carya illinoinensis ) plantations would be affected by their age. Based on MiSeq sequencing, we studied the effects of pecan age on microbial communities in rhizosphere and bulk soils of pecan plantations for the first time. The results showed that the bacterial alpha diversity of bulk soil increased significantly with plantation age ( p < 0.05), while fungal alpha diversity was less influenced by pecan age in both rhizosphere soil and bulk soil. Pecan age significantly influenced bacterial and fungal community structure in both rhizosphere soil and bulk soil ( p < 0.01). The fungal community composition was significantly altered by pecan age as reflected by the increase (22% in bulk soil and 18.4% in rhizosphere soil) and decrease (25.4% in bulk soil and 22.7% in rhizosphere soil) in the relative abundances of Basidiomycetes and Ascomycota , respectively. The pH value and available phosphorus (AP) content drove microbial community structure and composition. The bacterial network was more complex than the fungal network, and simpler and more stable microbial network structures occurred in the rhizosphere soil than in the bulk soil. With increasing plantation age, the risk from plant pathogenic fungi increased, and the functional profile of the microbial community shifted from the nitrogen cycle to carbon utilization.