Microbial,chemical and physical changes during composting of a eucalyptus (Eucalyptus calophylla and Eucalyptus diversicolor) bark mix

Summary Physical, chemical, and population changes among microorganisms in a eucalyptus bark mix were examined during composting. The microbial succession was studied in detail by dilution plating. The CO₂ evolution corresponded to high microbial numbers. The pH increased rapidly, from 4 to 7.5, before stabilizing at approximately 6.5. Composting increased the availability of most nutrients. Initially, bacteria and filamentous fungi appeared to be the main decomposing organisms. With time, however, yeasts and actinomycetes increased in numbers. The numbers of spore-forming bacteria (Bacillus spp.) and pseudomonads also increased with time. The compost was initially phytotoxic, but ceased to be so within 76 days.