A new conceptual model for the fate of lignin in decomposing plant litter

摘要: Lignin is a main component of plant litter. Its degradation thought to be critical for litter decomposition rates and the build-up soil organic matter. We studied relationships between lignin production dissolved carbon (DOC) CO2 during decomposition. Needle or leaf five species (Norway spruce, Scots pine, mountain ash, European beech, sycamore maple) different stage (freshly fallen up 27 months field exposure) was incubated in laboratory two years. followed with CuO method. Strong occurred first 200 incubation days, as revealed by decreasing yields lignin-derived phenols. Thereafter leveled off. This pattern similar fresh decomposed litter, it stands contrast common view limited Dissolved also peaked period but were not interrelated. In later phase incubation, positively correlated DOC amounts, suggesting that bioavailable, soluble compounds became limiting factor production. only when high, bioavailable carbon. Thus availability most important control on degradation. turn, could explain differences over study period. Our results challenge traditional regarding fate role controlled easily decomposable sources. Consequently, occurs particularly initial hampered at stages if resources decline.