Microbial community alteration driven by labile organic carbon enhances phosphorus availability under different tillage regimes

期刊论文
发表日期：

2024年10月23日

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Jiao Yang,
Xiuli Xin,
Xianfeng Zhang,
Xinyue Zhong,
Wenliang Yang,
Anning Zhu

摘要

Purpose

Organic carbon (C) application can improve soil C sequestration, but little is known about the impact of organic C-driven microbial community alteration on phosphorus (P) availability in soils with different tillage regimes.

Materials and methods

A 30-day incubation experiment was carried out in this study to explore the response of labile inorganic P content, organic P fraction, phosphatase activity, and phoD-harboring bacterial and fungal community structure and co-occurrence network to glucose (500 mg C kg⁻¹ dry soil) addition in 13-year continuous-tilled (CT) and no-tilled (NT) soils.

Results

The results showed that glucose addition significantly decreased the labile inorganic P content to the lowest value on Day 3 and then gradually increased by 13.1% and 25.9% in CT and NT from Day 3 to Day 30, respectively. On Day 30, the labile inorganic P content in CT was notably lower than that in NT, mainly due to the lower pH and higher phosphatase activity in NT. The labile organic C input shifted phoD-harboring bacteria from Actinobacteria (oligotrophic) to Proteobacteria (copiotrophic) and phoD-harboring fungi from Ascomycota to Basidiomycota. After glucose addition, Ensifer and Bradyrhizobium emerged as the dominant bacterial species in CT and NT soils, respectively, while Solicoccozyma became the dominant fungal species in both CT and NT soils. Regarding the combined bacterial and fungal co-occurrence network, stronger positive interactions among phosphate solubilizing microorganisms (PSMs), especially between bacteria and fungi, were detected in the glucose-amended treatment. This phenomenon was more evident in NT than in CT.

Conclusion

Overall, incorporating exogenous labile organic C could affect P availability by altering soil pH, phosphatase activity and the microbial community composition, and increasing the complexity of co-occurrence network topological patterns; more importantly, NT was more sensitive to labile organic C addition than CT.