Individual study: Earthworm populations in conventional and integrated farming systems in the LIFE Project (SW England) in 1990-2000
Hutcheon J.A., Iles D.R. & Kendall D.A. (2001) Earthworm populations in conventional and integrated farming systems in the LIFE Project (SW England) in 1990-2000. Annals of Applied Biology, 139, 361-372
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A replicated, controlled, randomized study of conventional and non-inversion tillage in six fields in Somerset, UK (Hutcheon et al. 2001) found that earthworm (Lumbricidae) abundance and species diversity were higher in non-inversion regimes using a Dutzi machine than in either non-inversion farming using a Vaderstad drill or conventional ploughing and drilling. From 1990-1994 there was no significant difference between density in Dutzi non-inversion plots (65/m²) and conventional plots (64/m²), but biomass was significantly greater in Dutzi plots in 1993 and 1994 (23-40 vs 13-16 g/m²). From 1995-2000, worm density was significantly greater in Dutzi plots than conventional plots in 1995, 1999 and 2000 (72-155 vs 38-66/m²); Vaderstad non-inversion plots did not differ from conventional plots (62-72 vs 38-66/m²). Biomass was significantly greater in Dutzi than conventional plots in all but one year (35-68 vs 16-31 g/m²); biomass in Vaderstad plots was only greater than conventional plots in two years (33-42 vs 16-19 g/m²). Thirteen species were recorded from 1995 to 2000, four of which were significantly more abundant in Dutzi than conventional plots; densities in Vaderstad plots were intermediate. There was no significant effect of treatment on the other six common species, although densities of four tended to be higher in Dutzi than conventional plots. Fields were divided into four plots (1 ha) which were assigned randomly to treatments. In autumn 1994-2000, an additional non-inversion tillage regime was included, using a Vaderstad disc coulter drill. Fertilizers and pesticides were also reduced (25-40% and 30-90% respectively) in non-inversion tillage regimes compared to conventional farming. Earthworms were sampled over one hour using diluted formalin on the soil in three quadrats (0.25 m²) placed at random/plot in March-April and September-October each year.