生物炭调控土壤细菌群落结构影响磷有效性的作用机制

Biochar regulates the soil bacterial community structure to affect phosphorus availability

摘要:

目的 探究生物炭通过改变土壤细菌群落结构进而影响土壤磷有效性的作用机制。方法 运用宏基因组学技术研究不同剂量生物炭(CK：0 kg/hm²；T1：300 kg/hm²；T2：600 kg/hm²；T3：900 kg/hm²)处理下土壤细菌群落及磷循环相关功能基因的变化。结果 施加生物炭显著提高土壤无机磷(inorganic phosphorus, IP)、微生物量磷(microbial biomass phosphorus, MBP)含量和碱性磷酸酶(alkaline phosphatase, ALP)活性，其中T2处理下的增幅分别为21.75%、699.39%、34.00%。施用生物炭改变了土壤细菌的多样性与丰富度，显著富集了放线菌门(Actinobacteriota)、酸杆菌门(Acidobacteria)、绿屈挠菌门(Chloroflexota)、热假单胞菌门(Thermoproteota)、芽单胞菌门(Gemmatimonadota)、类诺卡氏属(Nocardioides)以及鞘脂菌属(Sphingobium)。土壤pH、含水量、有机质(soil organic matter, SOM)、IP、MBP和速效磷(available phosphorus, AP)是影响细菌群落的关键因子。在磷循环功能基因方面，施用生物炭显著提高了有机磷矿化基因phoD的丰度，T2处理较CK处理增加9.28%，且phoD的丰度与全磷(total phosphorus, TP)、AP及MBP含量显著相关。结论 生物炭通过调控土壤细菌群落结构提升磷有效性，为生物炭在农田磷素管理中的应用提供了理论依据。

Abstract:

Objective To explore the mechanism by which biochar alters the soil bacterial community structure and thereby affects the availability of soil phosphorus.Methods This study employed metagenomic techniques to investigate the soil bacterial communities and microbial functional genes involved in the phosphorus cycle after the application of biochar at different doses (CK: 0 kg/hm², T1: 300 kg/hm², T2: 600 kg/hm², and T3: 900 kg/hm²).Results The application of biochar significantly increased inorganic phosphorus, microbial biomass phosphorus, and alkaline phosphatase activity, which showed the increases of 21.75%, 699.39%, and 34.00%, respectively, under T2 treatment. Furthermore, the application of biochar changed the diversity and richness of soil microorganisms, especially bacteria, mainly enriching Actinobacteriota, Acidobacteria, Chloroflexota, Thermoproteota, Gemmatimonadota, Nocardioides, and Sphingobium. Soil pH, water content, organic matter, inorganic phosphorus, microbial biomass phosphorus, and available phosphorus were important factors influencing soil microbial communities. In addition, biochar significantly increased the abundance of the organic phosphorus mineralization-associated gene phoD, T2 increased by 9.28% compared with CK, and the abundance of phoD was significantly affected by total phosphorus, available phosphorus, and microbial biomass phosphorus content in the soil.Conclusion The application of biochar can enhance phosphorus availability by regulating soil bacterial community structure. The findings provide a theoretical basis for the application of biochar in improving phosphorus availability in farmland soil.