Whether you till or not, did you have earthworms that aid your soil in developing root channels to loosen the soil and aid natural soil drainage? Maybe you no-till, maybe you don't. Maybe you no-till soybeans but then run a vertical tillage tool ahead of corn, or maybe you chisel plow after corn. Perhaps you run a field cultivator over soybean stubble before planting corn each spring.
Tillage methods can affect earthworm populations. Studies by Eileen Kladivko, Purdue University, have shown that to be true over the years.
What really matters is do you have earthworms or not? If you don't, would it be worth adjusting tillage practices to encourage more worm activity? Hay and pasture rotations are also good for encouraging earthworms to proper if they are in your field to begin with.
"The first step is to look for middens," says Roger Wenning, Greensburg. He's no-tilled for several years with very limited tillage in a few fields, and also uses cover crops. Recently he took a spade and went looking for earthworms.
"See the middens," he emphasizes. "There are earthworms under there that are pulling food into the center so they can drag pieces of it down their burrows. The food source is crop residue in this case. Since I leave as much residue on the surface as possible, there's a big supply of residue for them to work with."
Next Wenning took the spade and gently dug under the midden, lifting it up. Sure enough, at first he spotted an earthworm, then another, and then another. And he was only an inch or so below the surface in about a 6 inch by 6 inch area.
He says he finds a variety of types of worms, primarily nightcrawlers and redworms. He believes it's important to have the worms in the field do that they help improve soil tilth.