Biochar application under low phosphorus input promotes soil organic phosphorus mineralization by shifting bacterial phoD gene community composition

• Published in: The Science of the total environment Vol. 779; p. 146556
• Main Authors: Tian, Jihui, Kuang, Xizhi, Tang, Mengtian, Chen, Xiaodong, Huang, Fei, Cai, Yixia, Cai, Kunzheng
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 20.07.2021
• Subjects: C:P stoichiometry; Phosphatase encoding gene; Phosphodiesterase; Phosphomonoesterase; Phosphorus fractions; Phosphorus fractions; Phosphomonoesterase; Phosphatase encoding gene; C:P stoichiometry; Phosphodiesterase
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2021.146556

Biochar has the potential to enhance microbial-mediated phosphorus (P) cycling in soils, but the underlying mechanisms remain largely unknown. We hypothesized that biochar amendment could enhance the production of acid and alkaline phosphomonoesterase, phosphodiesterase and P mineralization, which may vary depending on the P input. To test this hypothesis, we assessed the impacts of rice straw biochar application (0 and 4%) under different P-input rates (0, 30 and 90 kg P ha−1) on the relationships among P fractions, phosphatase activities and alkaline phosphomonoesterase-encoding bacterial (phoD gene) communities in an acidic soil. Biochar application under low P input (< 30 kg P ha−1) significantly increased the activities of phosphodiesterase and alkaline phosphomonoesterase but not that of acid phosphomonoesterase and depleted organic P. The results from the structural equation model revealed a dominant role of alkaline phosphomonoesterase in P mineralization. The increase in alkaline phosphomonoesterase activity was not related to an increase in phoD gene abundance but was due to a shift in community composition, which was primarily driven by the soil C:P ratio. Microbial network analysis demonstrated a more complex phoD gene community with more functionally interrelated groups as a result of biochar application under low P input than under high P input. Moreover, the specific enrichment of Micromonosporaceae under C-rich and P-poor conditions may play a critical role in alkaline phosphomonoesterase production and potential P mineralization. In conclusion, we demonstrated that biochar application under low P input supports a more organized phoD gene community and preferentially enriches taxa in terms of their capacity for P mineralization, which in turn may enhance P bioavailability and plant P acquisition. [Display omitted] •We investigated how biochar with different P inputs affect biochemical P cycling.•Biochar application at low P input increases microbial-mediated P mineralization.•Alkaline phosphomonoesterase (AlP) activity is not related to phoD gene abundance.•Shift in phoD community composition driven by C:P is correlated with AlP activity.•Enrichment of Micromonosporaceae at high C:P ratio contributes to P mineralization.