CRM Legacy Data
National Crop Residue Management Survey (CRM)
Since 1982, the Conservation Technology Information Center’s (CTIC) National Crop Residue Management Survey (CRM) is the only survey in the U.S. designed to measure and track the type of tillage used by crop at the county level through personal observation of field conditions at mile or half mile intervals. Funding for the full national survey ended in 2004, though some states have continued to submit their own data since then.
Today, CTIC continues to offer public access to similar cropland management data for 2005 and beyond through the Operational Tillage Information System (OpTIS).
The CRM Survey reports tillage practices using the following categories
No-till
The survey reports a range from the absence of any tillage pass to practices causing minimal soil disturbance as "No-till". Residue levels range from 30 to 90% depending on previous crop.
Ridge-till
4 to 6 inch high ridges are built during row cultivation, with 1 to 2 inches scraped off the ridge during planting.
Mulch-till
Full-width tillage (100% of the soil surface is disturbed) that leaves more than 30% residue coverage after planting, often using implements such as chisel plows, discs, field cultivators, or combination tools.
Reduced-till
Similar to mulch-till leaving 15 to 30% of the soil surface covered by residue after planting.
Conventional tillage
Full-width tillage usually involving multiple tillage passes leaving less than 15% of the soil surface covered by residue after planting. Moldboard plows, discs, field cultivators, and combination tools may be used.