Interaction between dissolved organic matter structure diversity and phosphorus forms in phosphogypsum tailings under...

Exogenous organic input impacts soil phosphorus transformation. Meanwhile, dissolved organic matter (DOM) is crucial for biogeochemical functions. Nevertheless, the interaction between the structural composition of DOM and phosphorus during the soil formation process of phosphogypsum (PG) remains unknown. This study explores the interaction between the structural composition of DOM and phosphorus in enhanced PG under the participation of fungal microorganisms through different application amounts of exogenous organic matter and culture time. Results show that application of exogenous organic matter led to varying degrees of increase in dissolved organic carbon (DOC) concentration and humification extent in the soil-like substrate. Additionally, the relative abundance of protein-like component C3 exhibited a trend of initial increase followed by decline over time. The contents of available phosphorus (AP), microbial biomass phosphorus (MBP), and active phosphorus pools (Active-P) in the soil-like substrate are all enhanced overall. Furthermore, a significant correlation exists between DOC and AP as well as MBP. This suggests that DOM is a crucial factor in enhancing the phosphorus availability of the soil-like substrate. The enrichment of known phosphate-solubilizing fungi in culturing favors the decomposition, activation and utilization of hard-to-mineralize phosphorus components in the soil-like substrate. These findings help understand DOM's biogeochemical behavior and offer insights into PG utilization and the sustainable development of China's phosphorus industry.