Title : Soil carbon, nitrogen and phosphorus stoichiometry and its influencing factors in Chinese fir plantations across subtropical China
The soil carbon (C), nitrogen (N) and phosphorus (P) stoichiometry are key indicators of soil interior nutrient cycling and plant nutrient supply that play important roles in improving our understanding of biogeochemical cycling, and providing valuable information for forest management. To date, lots of related information was obtained from local scales, while little were focused on regional or larger scales, especially for a single plantation tree species. In this study, surface soil samples (0-20 cm) of Chinese fir (Cunninghia lanceolata (Lamb.) Hook) plantations across subtropical China were collected, and the C, N and P contents were measured. Results showed that the range of C:N, C:P, and N:P ratios were 7.32-18.27, 20.15-230.48, and 2.11-15.05, with mean value of 13.22, 83.50, and 6.05, respectively. Well-constrained correlations were found for SOC and TN, as well as TN and TP. Soil TN and TP contents increased with increased altitude, whereas soil C:N, C:P and N:P ratios decreased. Soil TP content decreased, and C:P ratio increased with increased mean annual temperature (MAT) and annual total solar radiation (ATSR). Soil C:N, C:P and N:P ratios increased with increased mean annual precipitation (MAP) and annual evaporation (AE). Our findings suggest that soil nutrients were in the state of relatively adequate supply and healthy nutrient cycling. Altitude and water indicators (MAP and AE) were the major geographical and climatic variables influencing soil stoichiometry, respectively. Overall, the results could shed light on the nutrient cycling in soil and the effects of climate changes on soil to provide valuable information for plantation management.