3.7 PLS-PM analysis
To better integrate the interrelationships among N application, tillage practices, microbial communities, soil enzyme activities, soil microbial CUEC:N, POC, and MAOC, we constructed a partial least squares path model (Fig. 9). The indirect effect of tillage treatments (0.38) on soil microbial CUEC:N was larger than that of N application (0.13). We further found that tillage management and N application affected microbial CUEC:N through changing soil bacterial diversity, fungal community structure, and fungus diversity more than bacterial and fungal biomass. The responses of microbial CUEC:N to bacterial and fungal diversity were also different (Fig. 9). Moreover, the results showed that microbial CUEC:N and soil enzyme activities had a direct effect on soil POC.