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 commun ities of decomposer microbes integrate physicochemical and population- level factors to control decomposition. To this end, we measured the r elationship between inoculation with Phanerochaete chrysosporium and P hlebia radiata and the evolution of CO2 from barley straw by decompose r communities. At 45-degrees-C, 80% as much CO2 was evolved from straw inoculated with P. chrysosporium in pure culture as from mixed cultur es containing P. chrysosporium or P. radiata with indigenous barley st raw and compost microflora. P. radiata in pure culture evolved less CO 2 than all other tested inocula. At 20-degrees-C, P. radiata evolved 3 -fold more CO2 in pure culture on barley straw over 42 days than did o ther tested inocula. Adding P. radiata to straw in co-culture with Tri choderma harzianum or indigenous barley straw microflora did not incre ase CO2 evolution, and by inference decomposition rate, compared to mi crocosms without added P. radiata. We conclude that community-level co ntrols on decomposition dynamics integrate physicochemical and populat ion-level controls, and therefore might facilitate extension to the en vironment.