VARIATION CHARACTERISTICS OF FOREST SOIL NUTRIENTS AND THEIR ECOLOGICAL STOICHIOMETRY IN SEJILA MOUNTAINS OF SOUTHEAST TIBET, CHINA

Carbon, Nitrogen, Phosphorus, and other nutrient contents and their ecological stoichiometric characteristics of forest soil are helpful to understand soil nutrient cycling pattern in alpine region. The soil samples of six consecutive altitudinal gradients (3800, 3900, 4000, 4100, 4200, and 4300 m) in the northern and southern slopes of Sejila Mountain in southeast Tibet (PR China) was collected in July 2021. The contents of total organic carbon (TOC), total nitrogen (TN), and total phosphorus (TP) were measured, and the ecological stoichiometric values were also calculated. Results showed that altitude had significant effects on N, P, and C/N (P < 0.05), slope aspect had extremely significant effects on C, P, C/N, and C/P (P < 0.01). Pearson analysis results showed that TOC was significantly positively correlated with TN, N/P, and C/P in the North slope. In the south slope, C/N was negatively correlated with TN and TP. TOC, NiN, and S were positively correlated with soil stoichiometric characteristics. TOC, TN, TP, NiN and slope aspect were the main controlling factors of soil stoichiometric characteristics. The results can provide a theoretical reference for the study of soil nutrient supply and interaction in alpine forest ecosystems.