Legume residue is also a preferred food source for earthworms. The presence of earthworms is an outward sign of a healthy soil, although their effect on crop production is indirect and long term. 2 Earthworms help increase pasture production. As a result animals return more manure to the soil which, in turn, also supports earthworms. No-till soils have both types, particularly nightcrawlers which use the duff layer for food.
Nightcrawlers form large, permanent burrows into the root zone.
The burrows improve drainage and increase soil aeration. Plant roots proliferate through the soil using the burrows as easy passage. Earthworm castings cling to the walls of burrows and provide nutrients to plants. No-till soils support several times more earthworms than conventionally tilled soils. Low soil disturbance keeps the worm burrows intact, and the duff layer provides food and protection from temperature extremes.