Effects Of Snow Storm On Soil Carbon And Nitrogen In Phyllostachys Edulis And Pinus Taiwanensis Forests In The Wuyi Mountains

Snow storm, as a significant natural disturbance, is one of the major drivers of ecosystem structure and function. We selected the Moso bamboo and Pinus taiwanensssis forests disturbed by snow storm in 2008 as sites in the Wuyi Mountains. The effects of this snow storm on the dynamics of soil labile organic carbon, available nitrogen under Moso bamboo and Pinus taiwanensis forests in different soil layers and decomposition of bamboo leaf litter were studied. The results showed that:(1) Moso bamboo forest mass loss rate was very quick firstly, then slow down. Leaf decomposition rates increased with increasing damaged level.(2) The annual mean concentrations of soil labile organic carbon (MBC, WSOC and ROC) in the Moso bamboo significantly increased with increasing damaged level in three soil layers. The annual mean concentrations of soil labile organic carbon(MBC and WSOC) in Pinus taiwanensis forest after the snow storm were significantly higher than those of the Pinus taiwanensis forest befor the snow storm in three soil layers.However, the annual mean concentrations of soil ROC not have significant difference in Pinus taiwanensis forest befor and after the snow storm.(3) Nitrate was the main form of soil total water soluble nitrogen in different damaged level Moso bamboo forest. The annual mean concentrations of soil available nitrogen(MBN, WSON and NO3--N) significantly increased with increasing damaged level in three soil layers. Ammonium was the main form of soil inorganic nitrogen in Pinus taiwanensis forest before and after the snow storm. The annual mean concentration of soil ammonium in Pinus taiwanensis forest after the snow storm was significantly higher than that befor the snow storm, but the annual mean concentration of soil nitrate not have significant difference in Pinus taiwanensis forest befor and after the snow storm.(4) There were significant seasonal dynamics of soil labile organic carbon and available nitrogen in different damaged level Moso bamboo forest and Pinus taiwanensis forest befor and after the snow storm. Generally, the concentrations of soil labile organic carbon and available nitrogen in spring and autumn were higher than those in summer and winter, or which in spring and summer were higher than those in autumn and winter.(5) The concentrations of soil labile organic carbon and available nitrogen decreased with soil depth in different damaged level Moso bamboo forest and Pinus taiwanensis forest befor and after the snow storm.The input of litter, the changes of environmental factors (the increase of soil temperature and moisture) caused by snow storm and the interaction of them made the significant increase of soil labile organic carbon and available nitrogen. So the increase of soil microbial biomass carbon or microbial biomass nitrogen could be the main adaptation response of holding soil nutrient in Moso bamboo forest and Pinus taiwanensis forest disturbed by snow storm. At the same time, owing to the death or reduced activity of vegetations caused by the snow storm, the fixation of soil labile organnic carbon and available nitrogen by vegetable roots decreased. Soil nutrient produntion might exceed the vegetable fixation after the immobilization of soil microorganisms. The soil carbon and nitrogen in the Moso bamboo forest could be lost from the ecosystem in the form of WSOC, WSON and NO3--N. The soil carbon and nitrogen in Pinus taiwanensis forest could be lost from the ecosystem in the form of WSOC and NH4+-N.