Surface residue has value because it contains nutrients that eventually can be available to a crop and carbon for soil organic matter, catches snow that might otherwise blow off the field, moderates temperatures, helps reduce erosion and improves the infiltration rate of rainfall. However, too much surface residue makes planting difficult and keeps the soil cool in the spring. Residue management should focus on the balance of retaining sufficient cover to optimize the beneficial effects with the detrimental effects of too much residue.
On CRP fields with plant growth taller than 12 inches, cutting and removing plant materials may be necessary prior to planting or other tillage operations. Haying CRP prior to any management is one way to reduce residues and is recommended for no-till systems.
Although fire can be an effective means of removing excessive residues, it often is discouraged because it will result in N and S loss, as well as intermediately decomposed organic matter that would result in greater soil health, reducing issues with soil crusting, erosion, trafficability and fertilizer requirements. Ash following fire may be blown away, resulting in loss of minerals P and K, and further increasing the cost of subsequent crop inputs. Burning also may result in significant wind/water erosion, degrading the soil.. Furthermore, fire bans frequently make burning residues unfeasible.
Volunteer tree growth larger than 1 inch in diameter also should be removed prior to planting or tillage. Smaller trees can be mowed, while larger trees that later will interfere with tillage or harvesting equipment may require cutting with a dozer blade.
Some form of tillage with or without haying can reduce surface residues significantly. If the soil can be made fit for planting with as little tillage as possible, the soil will remain protected from loss and retain any fertility that is gained during the CRP years.
At a scale of most harmful to least, moldboard plowing is the most effective method of incorporating residues, but it leaves the soil completely exposed to wind and water erosion and, therefore, is not recommended. Similarly, deep chiseling will blacken the soil, and generally will need disking with a heavy disc, such as the Wishek Disc to bury enough residue that the deep chiseling will not plug. A deep chiseling probably is tied with plowing for harmfulness, due to its habit of bringing up degraded subsoil, resulting in higher surface lime, increasing the risk of wind erosion and soil loss.
Disking with a heavy discs, such as a Wishek, may be preferred as a tillage tool because if set correctly, it may leave some residue at the surface to slow erosion. A field cultivator would be useless in CRP as a primary tillage tool. A vertical tillage tool may be effective if enough residue were removed through haying.
If tillage is chosen as a seeding prep option, fall tillage is preferred to spring tillage. Fall tillage may be impossible in some drier or wetter years, necessitating early spring tillage. Aerator rollers also can be effective in preparing CRP fields for crop production or grazing because they cut plant material into short enough lengths, allowing no-till planters to function effectively. The aerator roller sufficiently smooths the soil surface to allow effective tractor and machinery operation.
Some aerator rollers have blades mounted on the rollers to cut the standing or matted residue into 10-inch sections, which allows for direct seeding with single-disc, no-till planters; other models use 1-inch tubes or rollers to penetrate the soil. Aerator rollers level mounds created in CRP fields by rodents and other animals or other uneven field conditions.
Aerator rollers can be used to cut residues into manageable lengths and flatten animal mounds prior to no-till planting.
Double-chisel plowing followed by disking or harrowing will prepare CRP fields effectively for seeders with hoe or disc openers. A single double-disc operation also is effective to smooth uneven field conditions and would be the only operation necessary to precede planting with no-till single-disc openers. These spring operations will significantly dry the soil, resulting in poor crop stands during dry springs.
When using row planters for corn or soybean, using row cleaners is necessary to move residue away from the planting disc. Failure to use these will result in planter plugging and hair-pinning of longer residue, interfering with placing seed at the appropriate depth and with subsequent germination and growth.
Strip tillage may be a viable option for fields when row crops will be planted subsequently. Strip tillage generally is performed in the fall and can reduce residues effectively in the tilled strip, thus improving early season stand establishment and vigor while leaving substantial residue between the rows to aid in soil conservations and rainfall infiltration.