Date of this Version
FIELD CROPS I G-20, Cropping Practices Issued June 1990, 15,000
Crop residue left on the soil surface is one of the easiest and most cost-effective methods of reducing soil erosion. ~ Research in Nebraska and other Midwestern states shows ' that leaving as little as 20 percent of the soil surface covered with crop residue can reduce soil erosion by as much as one half of what it would be from residue-free conditions. Greater amounts of residue cover further limit soil erosion, Figure 1.
Residue reduces erosion in two ways. First, the residue dissipates raindrop impact energy, reducing the amount of soil that is detached. Residue also forms a series of intricate obstructions or small darns that slows any flowing water. This reduces the amount of soil that can be transported. (Refer to NebGuide G8I-544, Residue Management for Soil Erosion Control, for further details on the erosion process and the benefits of residue cover.)
Historically, the term "conservation tillage" was used to describe any tillage and planting system that did not use a moldboard plow.
The current definition of conservation tillage that has been adopted by the Soil Conservation Service specifies that at least 30 percent of the soil surface must be covered with crop residue following planting to reduce soil erosion by water. So when a Conservation Plan indicates conservation tillage will be practiced, the producer has agreed to leave a minimum of a 30 percent cover after all tillage and planting operations have been completed.
Many Conservation Plans specify that crop residue cover left after planting will be the primary erosion control method. The required amount of cover ranges from 30 percent (conservation tillage) to as much as 85 percent