Table 3. The relationships between relative abundances of microbial functional genes involved in carbon and nitrogen cycling and soil carbon or nitrogen components and enzyme activity by Mantel-test.

Soil carbon parameters	Microbial relative abundance	R value	P
Soil organic carbon	Carbon cycling genes	0.389	0.039
Oxidizable organic carbon	Oxidizable organic carbon degradation genes(Cellulose, Hemicellulose, Starch)	0.403	0.046
Water dissolved organic carbon	Carbon cycling genes	0.114	0.216
Soil microbial biomass carbon	Carbon cycling genes	0.500	0.020
Total soil nitrogen	Nitrogen cycling genes	0.382	0.050
NH4 +-N	Ammonification genes	0.296	0.089
No3 –N	Nitrification genes	0.302	0.079
Cellulase activity	Cellulase genes	0.342	0.046
Glucanase activity	Endo- and exoglucanase genes	0.351	0.022
Polyphenol oxidase activity	Polyphenol oxidase genes	0.046	0.626
Amylase activity	Amylase genes	0.358	0.027