Abstract: I compared the differences in the contents and stoichiometry of soil organic carbon (C), total nitrogen (N), total phosphorus (P), total potassium (K), available nitrogen (AN), available phosphorus (AP), and available potassium (AK) in Pinus yunnanensis secondary forest along an elevation gradient in northeast Yunnan. Results showed that (1) the concentrations of C, N, P, K, AN, AP, AK among elevations ranged 7.85-31.61 g·kg^-1, 1.08-2.11 g·kg^-1, 0.19-1.41 g·kg^-1, 3.65-15.10 g·kg^-1, 51.33-144.35 mg·kg^-1, 0.56-2.42 mg·kg^-1, 0.03-0.35 g·kg^-1, respectively; (2) with increases in elevation, soil C, N, P,P∶K, C∶N showed a trend of first increasing and then decreasing, whereas C∶P and N∶P showed an opposite trend; (3) Soil C content was positively correlated with N, AN, AP, AK,C∶N, C∶P, C∶K, N∶K or P∶K, but negatively correlated with K. These results suggest that the main soil nutrients and their stoichiometric characteristics of P. yunnanensis forest in this area varied obviously with altitude, with poor nitrogen and phosphorus status. Nutrient rich soil was found in the middle elevation, which is consistent with the growth performance of P. yunnanensis. Results from this study provide insights for understanding the growth and distribution of P. yunnanensis.

Key words: soil nutrient, ecological stoichiometry, elevation, Pinus yunnanensis.