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. Based
on MiSeq sequencing, we carried out the first study on the effects of
stand age on microbial communities in rhizosphere and bulk soils of
pecan plantation. The results suggested that soil bacterial alpha
diversity increased significantly with plantation age, while fungal
alpha diversity was less influenced. Bacterial and fungal biomarkers
differed by age group. The fungal community composition was
significantly altered by plantation age as reflected by the increase and
decrease in the relative abundances of Basidiomycetes and Ascomycota,
respectively. The pH and AP and TK contents 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.