Foliar Litter Decomposition: A Conceptual Model with Focus on Pine (Pinus) Litter—A Genus with Global Distribution
Figure 13
Oxidative enzyme activities (phenoloxidase and peroxidase) in white pine and pin oak foliar litter harvested during the first three years of a decomposition experiment. Values are given by treatment and averaged over sites and substrates. Statistical comparisons were only done for the 2- and 3-year harvests because of high numbers of zero values in prior harvests. An asterisk indicates that a particular treatment differed significantly from the control treatment at a particular harvest time. Values are means with standard error bars. Overall model R 2 values from 3-way analysis of variance (ANOVA) including treatment, site, and substrate as main effects were 0.34 and 0.24 for phenoloxidase and 0.22 and 0.23 after 2 and 3 years of decomposition, respectively. Control, carbon addition (25.5 g C m−2 y−1 as glucose), addition of inorganic N (10 g N m−2 y−1 as NH4NO3), addition of carbon (25.5 g C m−2 y−1 as glucose) and inorganic N (10 N m−2 y−1 as NH4NO3), long-term N additions (10 g N m−2 y−1 as NH4NO3 since 1999), (6) addition of non-N nutrients (P, K, Ca, Mg, S, Fe), (7) addition of organic N (10 g N m−2 y−1 as amino acids). From [77].
