Effect of Trichoderma on the Mineralization of Organic Carbon in Soil Aggregates

Propose  To investigate the effect of Trichoderma on mineralization of soil aggregate organic carbon, providing scientific evidence for carbon transformation in different aggregates.

Methods An indoor constant temperature incubation experiment with or without Trichoderma was conducted. Changes of the mineralization process of organic carbon and microbial community structure in bulk soil (BS), large macro-aggregates (LM), macro-aggregates (MA), and micro-aggregates (MI) were determined.

Results The application of Trichoderma had a significant impact on the mineralization of organic carbon and microbial abundance in different particle size aggregates. After Trichoderma addition, organic carbon in MA showed a positive priming effect , with an accumulated mineralization amount of 1587.67 mg/kg; while a negative stimulating effect was observed in MI, and Trichoderma promoted the turnover of organic carbon in MI, with an accumulated mineralization amount of 1778.33 mg/kg. The addition of Trichoderma could increase the relative abundance of Proteobacteria, which reduced the positive priming effect of organic carbon to some extent. The application of Trichoderma mainly changed the relative abundance of soil Ascomycota and Basidiomycota, thereby affecting the stability of organic carbon.

Conclusion Trichoderma can enhance the retention of carbon in micro-aggregates and affect the relative abundance of Proteobacteria, Ascomycota and Basidiomycota in the soil.