A method of extracting earthworms from cores of soil with minimum damage to the soil

Lumbricid earthworms have often been shown to increase the growth of plants. The earthworms and plants were generally grown together in the same soil, although sometimes earthworms were reluctant to enter the soil. It was not possible to isolate the mechanism for the increased growth, as no method was available to extract the earthworms with no damage to the soil before the plants were grown. A method is described which enabled Aporrectodea caliginosa, but not A. trapezoides, to enter all cores, and which extracted A. caliginosa from the cores probably with minimum damage to the soil.