Influence of beech litter fragmentation and glucose concentration on the microbial biomass in three different litter layers of a beechwood

摘要

In February 1993 samples of litter from three different litter layers (upper, intermediate, and lower) were taken from a beechwood growing on basalt soil. Using the substrate-induced respiration method, we investigated the influence of fragmentation and glucose concentration on the maximum initial respiratory response. Glucose concentrations ranged between 0 and 160000 μg g-1dry weight. The initial respiratory response reached a maximum at 80000 μg glucose g-1dry weight. The addition of higher concentrations of glucose resulted in negligible changes in respiration. Litter materials of four different size classes (intact leaves, fragmented<100 mm2,<25 mm2, and<5 mm2) were amended with 80000 μg glucose g-1dry weight. Substrate-induced respiration was at a maximum in the size class<25 mm2. The addition of glucose to intact litter did not result in microbial growth. It is concluded that C is not the primary limiting element for the microflora in litter layers of the study site. Fragmentation of beech litter enabled the microorganisms to grow. Presumably, nutrients that limited microbial growth in intact litter were mobilized by the fragmentation procedure and enabled microorganisms to grow in fragmented litter materia