ObjectTo study the role of soil enzyme activity and its ecological stoichiometry in limiting soil microbial nutrients and indicating soil nutrient availability.

Method Soil enzyme activity and its ecological stoichiometry, along with soil physical and chemical properties, were measured in Metasequoia glyptostroboides, Cryptomeria japonica var. sinensis, Larix gmelinii and Pinus armandii forests in Shennongjia National Nature Reserve.

Result The soil β-glucosidase (BG) activity in C. japonica, P. armandii and L. gmelinii forests was significantly higher than that in M. glyptostroboides forest. The soil β-acetylglucosidase (NAG) activity in L. gmelinii forest was significantly higher than that in other forests. There was no significant difference in soil acid phosphatase (AP) activity among the four types of forest stands. Soil BG∶NAG and BG∶AP in M. glyptostroboides forest were significantly lower than that in other forests. Soil BG∶NAG in L. gmelinii forest was also significantly lower than that in C. japonica and P. armandii forests. Soil NAG∶AP in L. gmelinii forest was significantly higher than that in other forests. Soil NAG∶AP (1.01±0.22) in the region indicated the soil microbes were limited by soil nitrogen. Redundancy analysis showed that soil organic carbon and pH value were important factors influencing soil enzyme activity.

Conclusion Forest stand is an important factor influencing soil enzyme activity and the ecological stoichiometry of soil enzyme. The effect on soil organic C and pH is the key factor regulating soil enzyme activity.