摘要
Litter is an important source of easily mineralizable C, N, and P for microbial metabolism in forest ecosystems;however, its decomposition is dependent upon a variety of biotic and abiotic factors, including litter chemical composition and plant specie, soil properties, and climate. We investigated C, N, and P mineralization patterns of pine litter, oak and a mixture of various species commonly found in wetland landscape position. Litter species were incubated (alone and with soils) under laboratory conditions in the dark for 120 days. Samples were leached weekly and the leachates were analyzed for pH, E4:E6 ratio, dissolved organic carbon (DOC), total N, NO3, NH4, soluble reactive P, and total P. CO2 effluxes during the 120-d incubation period were measure using NaOH traps. Carbon loss was calculated as the sum of DOC and CO2 effluxes. Results indicated that patterns of C and N release varied with litter species and soil type. Mix species treatment resulted in larger DOC and N pulses compared to pine and oak treatments. The majority of the DOC, N, and P leached was retained by the soils. When litters were added to the soils, a greater proportion of the C was lost as CO2, while litter incubated alone lost more C as DOC. This result demonstrated the importance of the soil microbial community affecting the patterns of litter mineralization. Total N concentration and C:N ratio of the litter species were significantly correlated to C loss.
Litter is an important source of easily mineralizable C, N, and P for microbial metabolism in forest ecosystems;however, its decomposition is dependent upon a variety of biotic and abiotic factors, including litter chemical composition and plant specie, soil properties, and climate. We investigated C, N, and P mineralization patterns of pine litter, oak and a mixture of various species commonly found in wetland landscape position. Litter species were incubated (alone and with soils) under laboratory conditions in the dark for 120 days. Samples were leached weekly and the leachates were analyzed for pH, E4:E6 ratio, dissolved organic carbon (DOC), total N, NO3, NH4, soluble reactive P, and total P. CO2 effluxes during the 120-d incubation period were measure using NaOH traps. Carbon loss was calculated as the sum of DOC and CO2 effluxes. Results indicated that patterns of C and N release varied with litter species and soil type. Mix species treatment resulted in larger DOC and N pulses compared to pine and oak treatments. The majority of the DOC, N, and P leached was retained by the soils. When litters were added to the soils, a greater proportion of the C was lost as CO2, while litter incubated alone lost more C as DOC. This result demonstrated the importance of the soil microbial community affecting the patterns of litter mineralization. Total N concentration and C:N ratio of the litter species were significantly correlated to C loss.
