Patterns of Mass loss,Nutrient Accumulation and Release of Leaf Litter in the Moso(Phyllostachys pubescens) Stands

Decomposition of leaf litter originating from Moso bamboo stands in five stand structure treatments with different stand density and different species component was measured at two trial sites over 104 weeks during 1993 to 1995.The mass loss rate can be expressed as the exponential function of decomposing time.The trial treatments have marked influences on the mass loss rate, which was higher in bamboo oak mixed stands and in pure bamboo stands of density 3015 culms·ha-1than in bamboo stands with other treatments.Patterns of N concentration change in decomposing leaf litter is very similar to that of P. They both increased during the whole decomposing process, by contraries, concentration of K、Ca and Mg decreased.No obvious effect of the different treatments was gotten on the dynamics of concentration of N、K and Mg.N was initially accumulated and lately released, while K、Ca and Mg were released from the decomposing leaf litter during the whole observation period.The release of N and P during the late stage was mainly caused by mass loss, but to K and Ca release, leaching is more important than mass loss, especially in the early stage of the decomposition.