Effect of the soil separation technique in potato fields on earthworm population

In a 2-year study effects of a special soil tillage on earthworms were investigated in potatoes. Soil separation is a tillage method mainly in potatoe production seperating stones and large soil particles from fine earth. The earthworms were sampled before and twice after soil tillage with the combined method of extraction and hand sorting. The initial status of earthworm populations was evenly distributed on a high level (167 g *m-2, 243 individuals m-2).<br>The abundance and biomass of earthworms were more reduced in the separated than in the traditional soil treatment (rotary harrow). One year after the tillage treatment the abundance was 20 % and the biomass 45 % less than in the traditional treatment. Nicodrilus longus, N. caliginosus, Allobophora rosea were most affected by soil treatments, no negative effects on Lumbricus terrestris and A. chlorotica were observed.