Earthworm populations recover after potato cropping

Potato cropping in southern Australia can involve up to 30 passes with a tractor, with up to 15 cultivations and multiple applications of fertilisers, fungicides, herbicides and insecticides. This was expected to significantly affect earthworm activity. Earthworms from four pasture sites were compared with those from adjacent potato paddocks. In the year following potatoes, earthworm numbers were about half in the paddocks which had been cropped. When the same sites were again sampled in the following year, populations had recovered and, on one field, were significantly higher in the second year after potatoes than in the adjacent pasture. This relatively rapid recovery, following substantial soil disturbance, may have been associated with the increased pH with lime added to the cropped paddocks.