A community-level concept of controls on decomposition processes: Decomposition of barley straw by Phanerochaete chrysosporium or Phlebia radiata in pure or mixed culture

We tested the hypothesis that interactions among populations in communities of decomposer microbes integrate physicochemical and population-level factors to control decomposition. To this end, we measured the relationship between inoculation with Phanerochaete chrysosporium and Phlebia radiata and the evolution of CO2 from barley straw by decomposer communities. At 45° C, 80% as much CO2 was evolved from straw inoculated with P. chrysosporium in pure culture as from mixed cultures containing P. chrysosporium or P. radiata with indigenous barley straw and compost microflora. P. radiata in pure culture evolved less CO2 than all other tested inocula. At 20° C, P. radiata evolved 3-fold more CO2 in pure culture on barley straw over 42 days than did other tested inocula. Adding P. radiata to straw in co-culture with Trichoderma harzianum or indigenous barley straw microflora did not increase CO2 evolution, and by inference decomposition rate, compared to microcosms without added P. radiata. We conclude that community-level controls on decomposition dynamics integrate physicochemical and population-level controls, and therefore might facilitate extension to the environment.