However, that might not be such a good idea for farmers growing crops without irrigation in regions receiving less than 25 inches of precipitation annually, says Ann Kennedy, a USDA-Agricultural Research Service soil scientist and adjunct professor of crop and soil sciences at Washington State University.


“With cultivation, organic matter tends to decline in most places around the world,” she said. “In the more than 100 years that we have been cultivating soils in the Palouse,”—the wheat growing region of Eastern Washington, Northern Idaho and Northeast Oregon—“we have lost about half of the original organic matter.”

Ideally, according to Kennedy, soils in the Palouse should have about 3.5 percent organic content. In most farm fields, she said, it is now closer to 2 percent.