Study of the relationship of nutrients dynamics and chemical composition of litter with decomposition rate in late decomposition stages

The late stage of decomposition process identified by that when decomposition and degradation of lignin had been occurred, i.e. at about 1 year after the incubation. The regulating factors for degradation of lignin, and thus of litter, in late decomposition stages are little known and we know very little about how they vary among litter species and sites with different climatic and edaphic conditions. Therefore, this study was done inorder to determine whether the control of lignin decay, and thus of litter mass-loss rate, by N, Ca and Mn in leaf litters of Norway spruce (Picea abies (L) Karst), Alder (Alnus subcordata C.A.Meyer) and Maple (Acer velutinum Boiss.) in pure and mixed Norway spruce sites after 400 day in lajim region. The results showed that decomposition rates of litter species exclusive of Maple, in mixed Norway spruce site were significantly higher than pure Norway spruce site. In the pure Norway spruce site decomposition rates of litter species were positively and significantly correlated with Mn and Ca concentrations, but had not significant correlation between Mn and Ca concentrations with lignin concentration. In the mixed Norway spruce site decomposition rates of litter species had significantly positively and negatively correlated with N and lignin concentrations respectively. Also in this site, there was negatively and significantly correlation between Ca and lignin concentrations. In relation with litter type, exclusive of needle litter, that Nitrogen amount is important regulating factor, nor of descriptive and qualitative factors (N, lignin, Mn, Ca) had not effect on the decomposition in late stage.