BARLEY STRAW DECOMPOSITION WITH VARIED LEVELS OF MICROBIAL GRAZING BY FOLSOMIA-FIMETARIA (L) (COLLEMBOLA, ISOTOMIDAE)

Folsomia fimetaria (L.) were added (0, 5, 10, 20 animals) to 0.100 g barley straw which had been inoculated 10 days (244 h) earlier with a natural soil microflora. Respiration (CO2 evolution) was monitored continuously. Mass loss, fungal standing crop (total and FDA-active), bacterial and protozoan biomass were estimated 42 days (1,000 h) after microbial inoculation. The degree of surface cover by hyphae was surveyed at regular intervals. No significant differences (P > 0.05) were found in respiration, mass loss or microbial biomass, but the density of surface hyphae were reduced by addition of Collembola. Fungal production was low, less than 5% of the estimated microbial production, and could not account for all collembolan growth during incubation. F. fimetaria appeared to consume mainly bacteria and protozoa, and had little impact on carbon mineralization.