Krogh, P. H.5; Griffiths, B.3; Demsar, D.3; Bohanec, M.3; Debeljak, M.3; Andersen, M. N.3; Sausse, C.3; Birch, A. N. E.3; Caul, S.3; Holmstrup, M.6; Heckmann, Lars-Henrik5; Cortet, J.3
1 Department of Terrestrial Ecology, National Environmental Research Institute, Aarhus University, Aarhus University2 Department of Bioscience - Soil Fauna Ecology and Ecotoxicology, Department of Bioscience, Science and Technology, Aarhus University3 unknown4 Department of Bioscience - Arctic Research Centre, Silkeborg, Department of Bioscience, Science and Technology, Aarhus University5 Department of Bioscience - Soil Fauna Ecology and Ecotoxicology, Department of Bioscience, Science and Technology, Aarhus University6 Department of Bioscience - Arctic Research Centre, Silkeborg, Department of Bioscience, Science and Technology, Aarhus University
Genetically modified crops (GM) may affect earthworms either directly through the plant, its root exudates and litter, or indirectly through the agricultural management changes that are associated with GM plant production. In order to investigate such possible effects we established two field studies of Bt corn and a glufosinate ammonium tolerant corn and included a reduced tillage treatment (RT) and a conventional tillage treatment (CT) as examples of a likely concomitant change in the agricultural practise. At a French study site at Varois, (Bourgogne), a field grown with the Bt-toxin producing transgenic maize line MON810 was studied for 1 year. At a Danish study site, Foulum (Jutland), one year of Bt corn was followed by 2 years of herbicide tolerant corn. At the French study site the most prominent effects observed were due to the tillage method where RT significantly reduced the earthworm populations to levels about half of CT. At the Danish study site effects of CT complied with known reduction of anecic earthworms due to this technique and likewise effects of RT were observed for endogeic earthworms. Earthworm populations were dimin-ished with the herbicide tolerant crop, probably due to exposure to the herbicide Basta® during the two consecutive autumn seasons. This study confirms the importance of including the tillage tech-niques and pesticide usage when evaluating the environmental effects of new agricultural technologies.