Dew worms can tunnel as deep as five feet. In other words, they mix the upper soil layers, much like a mouldboard plow. As well, earthworms drag crop residues and plant debris from the soil surface down into the burrows. On soils with good earthworm numbers, it's a key reason why soybean leaves disappear so quickly after leaf drop, Fox explains. Fortunately, no-till is inherently kind to earthworms.
Crop residues provide food and keep the soil surface cool and moist.
Growers may wonder whether, by eating residues and organic matter, earthworms rob the crop of a source of nutrients. Instead, says Fox, earthworms process organic matter together with soil, making nutrients such as nitrogen and phosphorus more available to the crop. Earthworms are most active in spring and fall when soil temperatures range from eight to about 18C. As summer approaches and the soil turns droughty and hot, earthworms will burrow deep into the soil, wrap themselves into a tight ball and go into aestivation, similar to hibernation. Fox tells growers to use her earthworm findings with caution. It isn't as simple as that.