Response of Forest Stand Types to Soil Stoichiometric Characteristics, Microorganisms and Their Seasonal Dynamics in Liziping Nature Reserve

Abstract

[Objective] To reveal the vertical distribution characteristics of soil organic carbon, nitrogen, and phosphorus content, soil stoichiometric characteristics (C/N, C/P, N/P), enzyme activity, microorganisms, and their seasonal responses of forest stand types in Liziping Nature Reserve. [Methods] The soils of Cyclobalanopsis and populus szechuanica broad-leaved mixed forest, Oriental oak deciduous broad-leaved forest, Fir-spruce coniferous mixed forest, and Yushania lineolata forest in the dry and rainy seasons were selected as the study objects to elucidate the effects of forest stand types on the stoichiometric characteristics of the soils, the enzyme activities, the microorganisms, and their seasonal dynamic response characteristics. [Results] (1) The soil physicochemical properties and enzyme activity of the four forest stand types are higher in the rainy season than in the dry season. (2) The soil C/N in the Cyclobalanopsis-populus szechuanica broad-leaved mixed forest is higher in the dry season than in the rainy season, while the other three stands show the opposite trend. Dry season's C/P are higher than the rainy season in Cyclobalanopsis and populus szechuanica broad-leaved mixed forest and Fir-spruce coniferous mixed forest, while the other two stands are the opposite. Dry season's N/P are higher than the rainy season in Oriental oak deciduous broad-leaved forest and Fir-spruce coniferous mixed forest, while the other two stands are the opposite. (3) Different forest types' value variation of soil C/N, C/P, and N/P are 17.00~37.33, 62.72~114.50, 3.09~5.18 in the dry season, and 17.72~39.16, 63.21~90.72, 2.39~5.80 in the rainy season. (4) The C/N and C/P values during the dry and rainy seasons are higher than the national average (11.90, 61.00), indicating that nitrogen is limited during nutrient cycling and the potential for releasing P is low; The N/P values for both seasons were lower than the national average soil level (5.20), indicating that the soil is more susceptible to N limitation; (5) The soil microbial activity of the four forest stand types is better in the rainy season than in the dry season, and the soil ecological stoichiometric characteristics are mainly influenced by enzyme activity and microorganisms. [Conclusion] The results of this study can provide important theoretical basis for exploring the seasonal response mechanisms of regional soil nutrient decomposition, supply and limitation, as well as nutrient cycling processes.

Keywords

• forest stand type
• stoichiometric characteristics
• enzyme activity
• microbial index
• seasonal dynamics