Abstract: To understand the relationship between soil arthropod and soil enzyme activity during litter decomposition, an experiment on decomposition of bamboo (Fargesia spathacea) leaf litter was conducted in a subalpine forest of western Sichuan. Soil arthropods were repelled by adding naphthalene to the forest floor. The effects of soil arthropod on the enzyme activities related to carbon, nitrogen and phosphorus transformation during litter decomposition were examined from April 2016 to April 2018. The results showed that the individual density and species richness of soil arthropod in litterbags were reduced by 49.7%-66.8% and 19.2%-46.3% with naphthalene addition, respectively. The enzyme activities related to carbon, nitrogen and phosphorus transformation in the treatment (naphthalene addition) and control (no naphthalene addition) litterbags showed similar dynamics. The presence of soil arthropod significantly increased the activities of invertase, β-glucosidase, cellobiohydrolase, polyphenol oxidase, peroxidase Nacetyl-β-D-glucosaminidase and acid phosphatase in decomposing bamboo leaf litter of the control litterbags. The contribution of soil arthropod to enzyme activity deceased rapidly after a peak value during litter decomposition. During the study period, soil temperature and species richness of soil arthropod showed positive correlations with invertase activity but negative correlation with the other enzymes. These results suggest that the stimulating effects of soil arthropods on enzyme activities differ with enzyme types and decomposition time, and have a close correlation with the soil arthropod community structure and decomposition environment.

Key words: Gynura bicolor, growth, secondary metabolites, light quality, stress treatment.