Abstract:

The current research focuses on soil particle separate and total organic carbon and nitrogen in Quercus aquifolioides forest in Balangshan, Wolong Natural Reserve, Sichuan, and their correlation at tree altitudinal gradient. The result shows that: The soil particle separate of Q.quifolioides forest is mainly of silts, and the soil texture is medium textured soils; The contents of soil total organic carbon content and nitrogen content in 0-15 cm layer are higher than that in 15-30 cm layer in different attitude gradients; the total organic carbon content in the topsoil shows a low-high-low tendency at different altitudinal gradients, whereas that of the subsoil shows a growing tendency; The C/N ratio of Q.aquifolioides forest is relatively small, with an average of 12.77; The correlation analysis between the soil total organic carbon and nitrogen content and soil particle separate respectively tells us: contents of soil organic carbon is very significantly positively correlated with total nitrogen in the two soil layers (P<0.01) at 3 549 m, no correlation at 2 551 m; the contents of total organic carbon and nitrogen are very significantly positively respective respectively with coarse silt content in 0-15 cm and 15-30 cm soil layers (P<0.05), but negatively with clay in different layers (P<0.05) in 0-15 cm soil layer at 3 549 m, significantly positively (P<0.05) and very significantly positively correlated (P<0.01) respectively with coarse silt content in different soil layers at 3 091 m, very significantly and significantly positively correlated respectively with fine sand content in different soil layers at 2 551 m, but negatively with fine silt content in 15-30 cm soil layer. Finally, in this paper the results presented that relationships among soil particle separate and total organic carbon and nitrogen content are quite complications in Q.aquifolioides forest at different altitudinal gradient.

Key words: Quercus aquifolioides, altitudinal gradient, soil particle, soil total organic carbon, total nitrogen, correlation analysis