Suppressed phosphorus-mineralizing bacteria after three decades of fertilization

Phosphorus (P) mineralization from organic matter is one of the most important microbially-driven soil processes in natural ecosystems. However, little is known about how long-term fertilization affect the abundance, diversity and community composition of these important organisms in croplands wherein P is directly supply via fertilizers. Here, we investigated the fate of phosphorus-mineralizing bacteria in a citrus plantation chronosequence (5-30 years) including information on management practices (no covering, straw covering and peanut covering after 15 years). We found that the diversity and abundance of phoD-harboring bacteria and the activity of phosphatase was largely suppressed after 30 years of fertilization. Moreover, long-term fertilization altered the bacterial community associated with P mineralization, decreasing the relative abundance of Methylobacterium, Aquabacterium and Rhizobacter in comparison with adjacent natural forests. Remarkably, land management practices associated with land covering helped to increase the diversity of phoD-harboring bacteria, after 15 years of experiment. This result is likely associated with the entrance of organic matter to the system. Our results provide new evidence that long-term fertilization drastically suppressed the abundance and diversity of bacteria associated with P mineralization, with implications for soil health and sustainability.