Earthworms and grassland productivity: impact of the New Zealand flatworm and slurry

摘要

Earthworms are the major component of the soil fauna in European temperate grassland. Their feeding and burrowing activities recycle nutrients, aerate and drain the soil: ultimately, improving soil fertility and grass yield. In Northern Ireland, concerns have been raised about the impact of New Zealand flatworm (Arthurdendyus triangulatus) predation and the effects of continual livestock slurry applications on earthworm populations. In a manipulative field experiment, A. triangulatus density of 0.8 m~(-2) reduced overall earthworm biomass by 20% but large anecic species of earthworm suffered a reduction in biomass of c. 74%. A reduction of this magnitude could reduce ryegrass above-ground herbage production by 6-7%. Application of cattle slurry, onthe other hand, largely benefitted earthworms, with epigeic species such as Lumbricus rubellus responding most positively.