Effects of earthworms and straw-decomposing microbial inoculants on straw decomposition and soil mineral-associated organic carbon formation
To explore the impact of earthworms and straw-decomposing microbial inoculants on straw decomposition and the formation of soil mineral-associated organic carbon,we conducted an incubation experiment with four treatments,i.e.,soil+straw(CK),soil+straw+straw-decomposing microbial inoculant(SM),soil+straw+earthworms(SE)and soil+straw+straw-decomposing microbial inoculant+earthworms(SME),to investigate interactive effects of straw-de-composing microbial inoculants and earthworms on soil greenhouse gas emission,bacterial and fungal abundance,soil aggregate structure,metal ion content,particulate or-ganic carbon content and mineral-associated organic carbon content.The results indicated that compared with CK,SE and SME treatments significantly increased the straw de-composition rate and promoted the emission of CO2 and N2O in soil.In addition,SE and SM treatments significantly increased bacterial abundance compared with CK,while there was no significant difference in soil fungal abundance among treatments.Compared with CK,SE and SME treatments signif-icantly increased the contents of extractable calcium and magnesium in soil,and significantly facilitated the formation of mineral-associated organic carbon and Ca/Mg-associated carbon.But there were no significant differences in aggregate structure and the contents of non-crystalline Fe and Al,particulate organic carbon and Fe/Al-associated carbon among treatments.Linear correlation analysis showed that mineral-associated organic carbon formation and Ca/Mg-associated car-bon were positively related with bacterial gene copy number and content of soil extractable Ca and Mg,respectively.In con-clusion,earthworms dominated straw decomposition and mineral-associated organic carbon formation,and the interactions between earthworms and straw-decomposing microbial inoculants did not further promote the decomposition of straw into mineral-bound organic carbon.
万方数据
维普
