How does phosphorus fertilizer improve the stability of soil aggregates? Evidence from a decade fertilization experiment

Phosphorus (P) fertilizer inputs can increase soil P availability, which improves soil carbon (C) cycling and microbial community structure. However, the potential mechanisms via which P drives soil organic carbon (SOC) and microbial regulation of aggregates formation and stabilization are still unclear. A 10-year field experiment was conducted, including (1) CK, no fertilization; (2) NK, N and K fertilizer addition; (3) NP1K and (4) NP2K, NK with 28 and 56 kg P ha−1 addition, respectively. Relative to NK treatment, long-term P fertilizer application significantly increased the proportion of >0.25 mm aggregates and mean weight diameter (MWD), which were increased by 16.4