We used a litterbag method to investigate litter decomposition and related soil degradative enzyme activities across four seasons in a broad-leaved forest and a coniferous forest on Zijin Mountain in sub-tropical China.Across four seasons, we quantified litter mass losses,soil pH values, and related soil degradative enzyme activities.Litter decomposition rates differed significantly by season.Litter decomposition rates of broadleaf forest leaves were higher than for coniferous forests needles across four seasons, and maximal differences in litter decomposition rates between the two litter types were found in spring.Obvious differences in litter decomposition rates of the two litter types were found in winter, which were similar to rates in spring.Litter decomposition rates of the two litter types in autumn were significantly higher than in spring.Soil degradative enzyme activities were lowest in winter and highest in summer in most cases across four seasons.
WANG Cong-yanLü Yan-naWANG LeiLIU Xue-yanTIAN Xingjun
Aims With the continuing increase in the impact of human activities on ecosystems,ecologists are increasingly interested in understanding the effects of high temperature on litter decomposition since litter decomposition and the accompanying release of nutrients and carbon dioxide are key processes in ecosystem nutrient cycling and carbon flux.This study was conducted to evaluate the temperature sensitivity of forest litter decomposition and soil enzymes during litter decomposition in subtropical forest in China.Methods Two dominant litter types were chosen from Zijin Mountain in China:Quercus acutissima leaves from a broadleaf forest(BF)and Pinus massoniana needles from a coniferous forest(CF).The litter samples were incubated in soil microcosms at ambient control temperature(20 C)and 10 C warmer.During a 5-month incubation,chemical composition of litter samples,litter mass losses,and related soil enzyme activities were determined.Important Findings Three main results were found:(i)high temperature accelerated decomposition rates of both litter types,and the temperature sensitivities of litter decomposition for BF leaves and that for CF needles are equivalent basically,(ii)high temperature enhanced soil enzyme activities in the two forest types,and the temperature sensitivities of polyphenol oxidase were significantly higher than those of the other soil enzymes and(iii)the temperature sensitivities of nitrate reductase were significantly higher in the CF soil than in the BF soil,while there was no significant difference in the temperature sensitivities of the other soil enzymes between BF and CF.As a long-term consequence,the high-temperature-induced acceleration of litter decomposition rates in these subtropical forests may cause carbon stored belowground to be transferred in the atmosphere,which may alter the balance between carbon uptake and release,and then alter the global carbon cycle in the coming decades.
