For producers using conservation tillage or no-till, it's important that every field operation leaves the maximum amount of residue cover on the soil surface. As a reminder, conservation tillage is defined as any tillage practice that would leave a residue cover over the soil surface of at least 30 percent or more. Complete residue cover reduces erosion 95 to 98 percent, compared with unprotected soil depending on type of residue (see Iowa State University Extension publication PM 1901a, Residue Management and Cultural Practices - Resources Conservation Practices).