Phosphorus cycling characteristics and soil microbial responses in different uneven-aged mixed forests of Pinus massoniana

Among the mixed stands, PT showed relatively higher microbial biomass P (MBP) and P use efficiency (PUE), exerting a better effect on alleviating P limitation. Distinct differentiation was observed in the P cycling functional taxa among different stands. Acidoferrum acted as the core taxon for P cycling across all stands, while PT harbored a unique taxon, CAIMXF01, facilitating P uptake and transport.

Notably, Streptomyces predominantly mediated inorganic P solubilization, while Rhizobium regulated organic P mineralization. The co-occurrence network between P cycling functional taxa and genes was relatively intricate in PT, and exhibited relatively high synergistic efficiency. Uneven-aged mixing of P. massoniana influenced P cycling by regulating the differentiation of functional taxa and genes, as well as the structure of their co-occurrence networks, and PT was more effective in alleviating P limitation and enhancing P cycling efficiency.