ECOLOGICAL STOICHIOMETRIC CHARACTERISTICS OF LEAF, LITTER, AND SOIL IN EUCALYPTUS PLANTATIONS WITH DIFFERENT AGES IN SUBTROPICAL, SOUTH CHINA
Chuan-Gui Xu, C. HU, Zhonghua Zhang, Xueli Peng, Gang Hu
Abstract
Understanding the ecological stoichiometry in the growth of different stand ages of Eucalyptus plantations is essential to evaluate the effects of management practices on biogeochemical cycling in plantation forest ecosystems.The study examined the relationship between leaf, litter, and soil stoichiometry on 3-, 6-, 9-and 12-year-old Eucalyptus grandis x urophylla plantations in subtropical China.Results showed that (1) With increased stand age, the concentrations of TN (total nitrogen) and TP (total phosphorus) in leaf and litter increased gradually.Leaf TC (total carbon) concentration decreased gradually, litter TC concentration initially increased and then decreased, and the concentrations of TC and TN in soil were opposite.Soil TC and TN concentrations decreased with increasing soil depth.(2) The ratios of C:N, C:P, N:P were litter > leaf > soil.With increasing stand age, C:N and C:P of leaf and litter decreased gradually, while the ratios of C:N, C:P, N:P of soil fluctuated greatly.(3) There were significant negative correlations between the C, N of soil and litter P and significant positive correlation was between the leaf C:N and litter C:P.The main limiting element was P. The results of this study can provide a scientific basis for the management of Eucalyptus grandis x urophylla plantations.