Field scouting usually happens in broad daylight. But to scout for one indicator of the vitality of your no-till fields, it’s best to step out after dark, or dusk at earliest. Then look for earthworms.

David Graham steps out of his red pickup truck and into the barren field. He pulls out his pocketknife, digs into the corn stalks and within 2 minutes uncovers two slugs — one brown and another one black. The slimy creatures slither up the silver blade of his knife.