Abstract: To understand the biogeochemical cycles in artificial forest ecosystem, fresh litter (leaf, twig, and fruit) of Quercus acutissima and Camptotheca acuminata in theQ. acutissima mixed plantation were monthly collected in the Rainy Zone of West China from November 2016 to October 2017. The changes in the concentrations of watersoluble carbon, nitrogen and phosphorus in the litter and their stoichiometry with the phenological rhythms (leaf sprouting stage, leaf expanding stage, frondent leaf stage, and senesced leaf stage) were investigated. Different trends of water-soluble carbon, nitrogen and phosphorus concentrations with phenological rhythms were observed in litter of Q. acutissima and C. acuminata, with different maximum and minimum values. Furthermore, the concentrations of water-soluble carbon, nitrogen, and phosphorus in leaf litter varied greatly with tree species and litter types. On the whole, the concentrations of water-soluble nitrogen and phosphorus in litter ranked as the order of fallen fruit>fallen leaf>fallen branch, while the concentration of water-soluble carbon in litter ranked as the order of fallen leaf>fallen fruit>fallen branch. The phenological rhythm significantly affected the stoichiometric ratios of water-soluble carbon, nitrogen, and phosphorus in the litter of both species, which varied greatly with tree species and litter types. Meanwhile, the interaction of tree species and phenological stages significantly affected the stoichiometric ratios. The results suggested that the phenological rhythm was a key factor affecting the concentrations and stoichiometric ratios of water-soluble carbon, nitrogen, and phosphorus in the litter of the Q. acutissima mixed plantation as well as tree species and litter types.

Key words: Soil bulk density, Soil water content, Split-root, Maize, Growth, Effect