Effect of earthworm and loach on Typha augustifolia aboveground and root litter residue in an integrated vertical subsurface flow constructed wetland

Abstract

A litterbag experiment was undertaken over 299 days (January to November, 2015) to investigate how earthworm and loaches affect aboveground and root litter residues of Typha augustifolia. An integrated vertical subsurface flow constructed wetland (IVFCW), for use in the experiment, was designed and built in a screen house at Nanjing University of Information Science and Technology. Results showed that the addition of earthworms and loaches into IVFCW significantly increased T. augustifolia aboveground and root litter N content in the influent chamber and effluent chamber at decomposition 299 days (p < 0.05). Similarly, addition of earthworms into IVFCW significantly increased P content of aboveground litter of T. augustifolia in the influent chamber at decomposition 213 days, and in root litter in influent chamber at decomposition 120 days (p < 0.05). With the addition of both earthworms and loaches, the T. augustifolia aboveground litter residual rate was negatively correlated with litter N and P content (p < 0.01), but a significant positive correlation between aboveground litter and C/N and C/P was evident (p < 0.01). Results suggest that earthworms and loaches in IVFCW may stimulate T. augustifolia aboveground and root litter decomposition, and decrease the accumulation T. augustifolia litter.