BEECH LEAF-LITTER LIGNIN DEGRADATION AND TRANSFORMATION AS INFLUENCEDBY MINERAL PHASES

To investigate whether lignin transformations are influenced by minera l phases, an incubation experiment with mixtures of beech leaf litter and Fe oxide, Al hydroxide, or birnessite was conducted. Fe oxide redu ced lignin decomposition to 39% of the lignin initially present as com pared to 50% in the control, whereas in the Al hydroxide experiment on ly 11% of the lignin was degraded. Lignin side chain oxidation was enh anced in the presence of Fe oxide and birnessite. The most important p roperties of the mineral phases, with respect to their influence on li gnin transformations, are their effect on microbial availability of or ganic matter and their ability to oxidize organic compounds. (C) 1998 Elsevier Science Ltd. All rights reserved.