Earthworm communities in conventional wheat monocropping and low-input wheat-clover intercropping systems

A comparative study was conducted on earthworm communities in a conventiona l winter wheat monocropping system and a low-input intercropping system in which successive crops of winter wheat were direct-drilled into a permanent white clover sward. Earthworm abundance, biomass and species composition u nder the two cropping systems in the second and third years of successive c ropping were assessed each spring and autumn in farm-scale field plots at f our sites using formalin and electrical extraction methods. The wheat-clove r cropping system supported larger earthworm communities (overall mean abun dance 548 individuals m(-2), 137 g biomass m(-2)) than conventional wheat m onocropping (194 individuals m(-2), 36 g biomass m(-2)). Between one and fi ve more earthworm species were recorded in the wheat-clover system than in the wheat system at three out of the four study sites. Wheat-clover croppin g especially favoured species belonging to the epigeic and epigeic/anecic e cological groups such as Lumbricus castaneus, L. festivus, L. rubellus, juv enile Lumbricus and Satchellius mammalis. Earthworm communities in the whea t-clover cropping system were comparable in size and species composition to communities normally found in perennial grassland-type habitats such as pa stures and grass-legume leys.