Effects Of Several Fungal Communities On Litter Decomposition And Nutrient Cycling

Litter decomposition is the major course of the material cycling and energy flow in forest ecosystem and it plays an important role in improving stand nutrition, improving forest productivity, maintaining the balance of ecosystem. Microbial disintegrators have a significant impact on litter decomposition through their own growth activities and the secretion of related enzymes. To explore the effects of the fungal communities on decomposition rate and nutrients circulation in the process of litter decomposition, three strains of fungus, Irpex lacteus, Collybia subnuda and Trametes hirsuta, separated and purified from Chinese Pine (Pinus tabulaeformis) plantations were as the tested strains, which combined to form 7 kinds of fungal communities. Chinese pine needles and Mongolian oak broad-leaved litter and their mixture (1:1) to form three types of medium. The experiment was carried out under the condition of same decomposition environment in the laboratory through the method of pure fermentation. The dynamics of mass loss, content of C、N、P、K, ration of C/N、C/P、N/P and activity of laccase and carboxymethyl cellulase (CMCase) were tested in the process. Results showed:(1) Irpex lacteus、Collybia subnuda and Trametes hirsuta had effects on litter decomposition rate, the degradation capacity were positively correlated with the activity of laccase and carboxymethyl cellulase, for Trametes hirsuta> Irpex lacteus> Collybia subnuda; the fungal communities,which has two or three kinds of fungal.degradation ability greater than or equal to the single fungi community. It was showed that fungal diversity improved the performance of the fungal community significantly.(2) Fungal communities had significant effects on the nutrient cycling (C, N, P, K,) in the litter decomposition process. Irpex lacteus and Trametes hirsuta were beneficial to nutrients release and increasing fungal diversity was conducive to the nutrients release in decomposition process.(3) Litter properties significantly affected decomposition rate and the release of nutrients (C, N, P, K.), for broad-leaved> mixed> needles.(4) A non-additive effect existed in the decomposition process when the two kinds of litter were mixed. For broad-leaved litter, the maximum increase of weight loss rate was 50%. For coniferous litter, the maximum increase of release of N, P and K was 130%,163% and 122%, respectively.