| The effects of a temperate intercropping system on spatial and temporal distribution of earthworms (Lumbricidae) over five sampling periods, from 1997 to 1998, were investigated at the University of Guelph Agroforestry Research Station and on a private farm in Ailsa Craig, Ontario, Canada.; Earthworm density and biomass were highest closer to the tree rows, however, variations occurred seasonally or as a result of tree species treatments. The highest total earthworm density across all positions, 394 individuals, was observed in spring 1997 under the poplar treatment. White ash and silver maple treatments had 379 and 257 individuals in the spring 1997 period, respectively. The highest spring period total earthworm biomass was observed under the white ash treatment, 735 g, followed by the poplar and silver maple treatments with 457 and 440 g, respectively.; At Ailsa Craig, the asparagus field had the largest change in total earthworm density. In the spring 175 individuals were observed as compared to 8 individuals in the summer. The tree-based land use systems had total earthworm densities ranging from 225--600 individuals in the spring and 80--285 individuals in the summer.; These studies indicate that tree-based cropping systems are more successful in maintaining high earthworm populations. |
