Effects of chemical composition on the rate and temporal pattern of decomposition in grassland species leaf litter

Abstract

We examined the effects of the chemical composition of leaf litter on the rate and temporal pattern of decomposition for 15 grassland plant species. Respiration rates (CO 2 flux) of soil treated with leaf sections of each species were measured periodically at 15 days, 30 days, 45 days and 60 days after incubation under laboratory conditions to monitor temporal changes in decomposition. Results showed that soil respiration rates of the plant species differed significantly at all four measurement times. The soil respiration rate at the earliest measurement (15 days) was positively correlated with the leaf N content, but the rates at the later measurements (30–60 days) were significantly correlated with the phenol : N ratios of litter types, indicating that contribution of litter chemicals changes with progression of decomposition processes. The one‐phase exponential decay curve well represented the temporal changes in the soil respiration rate. The relative rate of decline in soil respiration with time differed significantly among the plant species, and it was correlated significantly and positively with litter N content and negatively with the litter tannin content, indicating importance of litter chemical composition on temporal pattern of decomposition. These results indicate the importance of soil CO 2 flux measurements at temporal scale.