Characteristics of Soil <scp><i>phoD</i></scp>‐Harboring Bacteria and Phosphorus Availability in Subtropical Chinese Fir Plantations

ABSTRACT Phosphorus (P) availability constrains plant productivity in forest ecosystems, with soil functional genes involved in P cycling playing a pivotal role in regulating its availability. However, the effects of climatic gradients on P availability and functional genes remain unclear. We collected 90 soil samples from subtropical Chinese fir plantations along a north‐to‐south gradient to evaluate the impact of soil phoD ‐harboring bacteria on P availability, employing high‐throughput sequencing and a biologically based approach. The lowest organic P was observed in mid subtropical (0.35–1.48 mg kg −1 ) region compared to south (1.27–2.69 mg kg −1 ) and north (0.81–2.34 mg kg −1 ), with inconsistent trends in inorganic P. Lower diversity and stronger competition of phoD in south and north subtropics, and higher diversity and stronger collaboration in mid subtropics. Actinobacteria positively correlated with organic P and was its strongest predictor (Increase in mean squared error = 17.63%). Mechanistic modelling indicated that variations in soil nutrients and pH from north to south altered competition among phoD and dominant species, thereby enhancing acid phosphatase activity and shifting organic P mineralization. Our findings highlight that increased competition among phoD may enhance P availability in P‐poor soils under climate warming. Collectively, this study offers novel insights into how climate impacts soil P availability in Chinese fir plantation soils.