Effect of organic material addition on active soil organic carbon and microbial diversity: A meta-analysis

Organic materials are integral to the soil carbon cycle in agricultural ecosystems, yet their specific impacts on soil organic carbon (SOC) and microbial diversity are not fully understood. In this study, we analyzed 188 data pairs from 57 published papers to assess the effects of various organic materials on SOC composition and microbial diversity across different farmlands. Our findings indicate that the addition of organic materials consistently enhances SOC composition and promotes both bacterial and fungal diversity. Notably, the particulate organic carbon (POC) fraction exhibited the most significant increase (42.35%), suggesting that POC is the primary pathway for organic carbon accumulation. Our analysis also identified the type of organic material as the leading factor influencing soil active carbon fractions and microbial diversity, with compost emerging as the most effective material for boosting soil carbon sequestration and microbial richness. Interestingly, while both dissolved organic carbon (DOC) and microbial biomass carbon (MBC) increased with organic material addition, a negative correlation between these two components was observed. This study advances our understanding of the complex interactions between organic materials, SOC components, and microbial diversity, providing valuable insights for the development of sustainable soil management practices aimed at enhancing soil carbon storage and agroecosystem health. [Display omitted] •Organic material enhanced active SOC components and microbial diversity.•Material type is a key determinant of soil carbon composition.•The main factor of SOC increase was the accumulation of POC.•MBC has a potential competition with DOC.