INFLUENCE OF BEECH LITTER FRAGMENTATION AND GLUCOSE-CONCENTRATION ON THE MICROBIAL BIOMASS IN 3 DIFFERENT LITTER LAYERS OF A BEECHWOOD

In February 1993 samples of litter from three different litter layers (upper, intermediate, and lower) were taken from a beechwood growing o n basalt soil. Using the substrate-induced respiration method, we inve stigated the influence of fragmentation and glucose concentration on t he maximum initial respiratory response. Glucose concentrations ranged between 0 and 160 000 mu g g(-1) dry weight. The initial respiratory response reached a maximum at 80 000 mu g glucose g(-1) dry weight. Th e addition of higher concentrations of glucose resulted in negligible changes in respiration, Litter materials of four different size classe s (intact leaves, fragmented<100mm(2) <25 mm(2), and <5 mm(2)) were am ended with 80 000 mu g glucose g(-1) dry weight. Substrate-induced res piration was at a maximum in the size class < 25 mm(2). The addition o f glucose to intact litter did not result in microbial growth. It is c oncluded that C is not the primary limiting element for the microflora in litter layers of the study site. Fragmentation of beech litter ena bled the microorganisms to grow. Presumably, nutrients that limited mi crobial growth in intact litter were mobilized by the fragmentation pr ocedure and enabled microorganisms to grow in fragmented litter materi als.