Changes in the Microbial Biomass and Metabolic Quotient During Leaf Litter Succession in Some New Zealand Forest and Scrubland Ecosystems

The soil microbial biomass and microbial metabolic quotient (respiration: biomass ratio) was measured in 16 forest and scrubland ecosystems throughout New Zealand, on materials representing successional stages of plant litter and its subsequent incorporation into the F-H and mineral soil layers. Microbial biomass usually peaked in the L 1 layer and then declined. The microbial carbon:organic carbon ratio decreased sharply between the F-H layer and the underlying mineral layer, indicating that a stress factor (possibly pH) reduced the proportion of organic matter immobilized in the microbial biomass at this stage. The microbial respiration: biomass ratio declined between the L 1 and F-H stages