The Effect of Earthworm ( Lumbricus terrestris L.) Population Density and Soil Water Content Interactions on Nitrous Oxide Emissions from Agricultural Soils

Abstract

Earthworms may have an influence on the production of N 2 O , a greenhouse gas, as a result of the ideal environment contained in their gut and casts for denitrifier bacteria. The objective of this study was to determine the relationship between earthworm ( Lumbricus terrestris L.) population density, soil water content and N 2 O emissions in a controlled greenhouse experiment based on population densities (90 to 270 individuals m − 2 ) found at the Guelph Agroforestry Research Station (GARS) from 1997 to 1998. An experiment conducted at considerably higher than normal densities of earthworms revealed a significant relationship between earthworm density, soil water content and N 2 O emissions, with mean emissions increasing to 43.5 g ha − 1 day − 1 at 30 earthworms 0.0333 m − 2 at 35% soil water content. However, a second experiment, based on the density of earthworms at GARS, found no significant difference in N 2 O emissions (5.49 to 6.99 g ha − 1 day − 1 ) aa a result of density and 31% soil water content.