Dan Gillespie wonders if long-time no-tillers are taking full advantage of the improvements in their soils. Gillespie, a continuous no-tiller in Meadow Grove, Neb., for the past 15 years, is putting his own soils to the test and sharing his answers.

He no-tills a corn and soybean rotation on 720 acres of silty clay loam soils that usually get 25 to 28 inches of rain a year. Fifty-five percent of the land is irrigated. He started farming in 1974, became a no-tiller in 1987 and moved into continuous no-tilling in 1989. He also works part-time for the Natural Resources Conservation Service.

Gillespie notes that no-tilling increases soil organic matter by approximately a tenth of a percent each year. “After 15 years, that’s a significant 1.5 percent increase,” he says.

Counting Carbon

Just 1 percent of organic matter equals 20,000 pounds per acre and offers a wealth of crop nutrients, he adds, including 10,000 pounds of carbon. “Only about 1 percent of that is available in any given year, but it’s out there for us to use,” he says.

That 1 percent also offers 67 to 200 pounds of phosphorus, 250 to 300 pounds of calcium, 110 to133 pounds of magnesium and 123 to 145 pounds of sulfur. “Those are important nutrients and micronutrients. Are we taking advantage of them?,” he asks.

That’s what Gillespie hoped to do when, in 2002, he cut back his nitrogen applications from the standard 1.2 pounds per bushel of corn yield goal and relied on…