科研之友
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摘要
Long-term studies of Common beech litter decomposition are scarce and the relationship of its limit values to nutrients/heavy metals dynamics has not been sufficiently studied. The present study is a rare case in which beech litter decomposes almost entirely and enables analyses of the impacts of nutrients and heavy metals on litter decomposition. The aim of the present paperis to (i) determine a decomposition pattern of leaf litter and estimate the limit values and to (ii) determine the dynamics of the main nutrients and heavy metals (concentration and net amounts, based on ash-free litter) in an unpolluted stand of Common beech. Common beech (Fagus sylvatica L) leaf litter was incubated in polyester litterbags (1.5 mm mesh size) and 41 samplings were made over a period of 6.5 years until a mass loss of 88.9% was achieved. Carbon (C) plus 12 more nutrients and heavy metals were analyzed. Mass losses of both whole litter and of C were used in order to estimate the limit values as well as to determine significant differences between the two approaches. An asymptotic function gave significant limit values that were close to 100% (p < 0.0001).These results were also supported by a single exponential p <0.0001). The initial increase in concentrations of nutrients was followed by a decrease of N, P, K, Ca, Na and Mn. A similar pattern was observed for some of the heavy metals (Cu, Cd and Fe) while Zn concentrations decreased continuously. A net release (e.g. a decrease in the net amounts) was observed for all nutrients and heavy metals except for Cd. The litter fraction did not leave any stable residues (i.e. limit values were close to 100%), which was at least partly due to the low initial N and very high Mn concentration (20 times higher than in other studies).
- 出版日期2014
