Variations in Ecological Stoichiometry Characteristics of C, N and P in Soils Beneath an Abies fanjingshanensis Forest

Spatiotemporal changes in the ecological stoichiometry characteristics of soils beneath an Abies fanjingshanensis forest and their driving factors were investigated to provide essential data for the conservation of this species. The soil physical and chemical indices beneath an A. fanjingshanensis forest in different years were studied. Specifically, the ecological stoichiometric characteristics of soils in 1980, 2000, and 2020 were compared through field sampling and laboratory analysis. The organic matter content in different years was 2020>2000>1980. In general, soil pH, soil organic matter, total nitrogen and available phosphorus displayed an increasing trend, while total phosphorus, total potassium and available potassium contents did not change significantly, and the alkali hydrolysable nitrogen content showed a gradual increasing trend. Specifically, C/P and N/P ratios in the 0-20 cm soil layer maintained an upwards trend, but the variation of C/N in soils was insignificant. Over time, the content of soil sand increased, whereas the clay contents decreased; moreover, the content of cations was much lower than the average value in Chinesee soil. Among the variety of influencing factors, soil silt was significantly negatively associated with pH. Sand was significantly positively associated with available P, while clay particles were significantly negatively associated with available P. In summary, P in soil is the principal factor restricting the growth of A. fanjingshanensis.