While leafing through a Plow & Hearth catalog a few days ago, I spotted a unique product that made me think of the many benefits of no-tilling.
In this catalog for backyard gardeners, environmentally friendly “red wiggler earthworms” were being sold for $29.95 per pound. The sales copy indicated these worms could increase the amount of aeration and productivity of a compost pile, garden soil or raised vegetable beds.
This got me to thinking about the tremendous value of the earthworms in no-tilled fields.
I contacted Ray Weil, the University of Maryland researcher who spoke about earthworms and soil quality at last winter’s 19th annual National No-Tillage Conference.
I asked him to estimate how many pounds of earthworms there might be with various forms of tillage.
Depending on soil texture, crop rotation, the use of cover crops and climate, he said high-quality soils no-tilled for more than 20 years likely contain 2,000 pounds of earthworms.
By comparison, heavily tilled soils might contain only 200 pounds of earthworms per acre.
Doing the math based on the catalog price of $29.95 for a pound of “red wigglers,” the worms in the no-till field would be valued at $59,900.
Worms in the moldboard-plowed field would be worth only $5,990.
For a grower with 900 acres of no-tilled crops, a ton of the worms per acre, at those prices, is worth an amazing $5.4 million!
Worms Do Your Plowing
As no-tillers know, the number of earthworms in your fields is the best indicator of soil life.
In The Farmer’s Earthworm Handbook, Purdue University soil management specialist Eileen Kladivko points out that the feeding, casting and burrowing action of earthworms is similar to plowing. The worms do underground plowing by stirring the soil and mixing crop residue, air and water into the soil profile.
An acre of no-tilled ground containing 2,000 pounds of worms would equal about 25 earthworms per square foot. Each year, this ton of worms would produce 100 tons of castings — the equivalent of spreading two-thirds of an inch of manure on the surface.
Illinois crop consultant Bill Becker has analyzed the nutrients that a ton of worms typically add to an acre of no-tilled soil each year.
His results showed the worms produced 4 pounds of nitrogen, 30 pounds of phosphorus, 72 pounds of potash, 90 pounds of magnesium and 500 pounds of calcium.
Researchers have found no-till crop rotations and cover crops definitely boost earthworm numbers. Soil researchers say the key is to offer a smorgasbord of crop residue to choose from, with different types of leaves and root structures.
Research in North Dakota shows earthworm numbers increased by 51% when the amount of surface residue in no-tilled fields went from 45% to 90%.
And earthworm numbers really tend to increase after the fourth or fifth year of no-tilling.
If you wanted to buy some worms, what would be the best way of seeding them in your no-till fields? Kladivko suggests placing 4 or 5 worms under some kind of mulch every 30 to 40 feet, preferably on a cloudy, wet, cool day.
Banking Worm Value
But at $29.95 per pound for “red wigglers,” it’s much cheaper for farmers to switch to no-till to get the full benefits from these underground profit-builders.
And when you have a talk with your banker about financing next year’s cropping operation, don’t be afraid to drop that $59,900 worm value per acre figure onto your balance sheet. If nothing else, it will draw his attention to the many benefits for no-tilling.