Date of this Version
Conservation Tillage, Conservation Technology Information Center, 1992.
Cultivation, a proven weed control methods, should be used primarily to control weeds, rebuild ridges, or aerate poorly drained or crusted soils. Cultivating just to stir the soil usually dries the soil and can result in lower yields during drier cropping conditions. For example, cultivating during warm and windy conditions can result in ¼ to ¾ inches of soil moisture loss.
The main difference between a conservation tillage cultivator and a conventional cultivator is the ability to handle residue and penetrate the soil. By definition, conservation tillage should leave at least 30 percent of the soil surface covered with crop residue after planting. Conservation tillage includes several tillage systems that have preplant tillage operations to loosen the soil as well as no-till and ridge plant systems.
Conservation tillage cultivators look much like conventional cultivators. However, the three to five shovels per row of a conventional cultivator generally are reduced to a single shank having a wide sweep or horizontal disk. To allow residue to flow past this shank, a coulter is usually mounted in front of it to cut the residue.
Shovel located adjacent to the rows on a conventional cultivator have been replaced with barring-off disks. These disks cut residue and can be set to move soil either toward or away from the row and control weeds in areas not undercut by the wide sweep. Some manufacturers use an extra wide sweep to eliminate the need of barring- off disks.
The point of the weep must be operated below the soil surface at a depth sufficient to keep soil moving over the sweep. This helps avoid plugging because the residue is carried by the soil through the cultivator. However, excessive depth can cause soil slabbing and poor weed control because weeds are still rooted in chunks of soil.
Soil penetration must be considered when electing a cultivator for no-till and ridge plant system. The cultivator must carry enough weight to penetrate untilled oil and to cut large amounts of residue. Manufacturers often make this weight available with heavier and stronger shanks, frame members and tool bars. Down pressure springs are often used to transfer weight from the tool bar to the individual row units.