click image to zoom This new equipment varies by manufacturer, but in a basic configuration consists of coulters, disks, and a subsurface knife for injecting fertilizer. Strip-tillage can be performed in the fall or spring before planting. Tillage equipment must be designed to match planting equipment because consistent seed placement within the tilled area is critical to gain the benefit of the tilled strip.
Strip-till performance is still being evaluated as the practice is fairly new. In the upper Midwest, some research shows continuous corn production using strip-till has improved over no-till (Table 1). As predicted, crop emergence has improved, with more uniform stands and better seedling vigor. In the same study, however, little response to tillage was seen in corn rotated with soybean.
click image to zoom Grain yields in strip-till have shown a limited advantage over no-till, varying with annual weather conditions. In a recent study conducted in Iowa, fall strip-till and fall chisel plow showed the only significant tillage effect on corn production in only 1 of 4 site-years (Table 2). Even with this limited success of corn in strip-till, interest in use of strip-till has expanded into other crops.
Strip-till as a Transitional Tool
Most strip-till implements have a fertilizer shank that allows placement of fertilizer at depth within the tilled zone. Some irrigated corn producers in western Kansas now use strip-till to help manage fertilizer applications in continuous corn systems. In these high-yielding environments, continuous high-residue levels limit adoption of no-till. Most producers apply nitrogen in the fall as anhydrous ammonia. The strip-till implement provides an opportunity to retain a large amount of residue, while still clearing a path for planting and putting down more than half of the annual nitrogen requirement for corn. These Kansas irrigators have adopted this tillage tool as a transitional tool. Without the use of strip-till, the majority of these producers would use some form of complete tillage to reduce residue in order to stay in a continuous corn system. Using strip-till provides a way to manage within high-residue systems. Since two-thirds of the field retains residue in strip-till, the overall effect will be to improve soil and water conservation.
The lesson to learn from the irrigators is that strip-till can be used to help transition traditional tillage systems into less tillage intensive systems. For dryland production, most no-tillers would argue that a strip-till machine isn’t necessary. They are comfortable planting through high-residue fields and managing weed and disease pressure through crop rotations. Still, many traditional producers are reluctant to try no-till. Either they lack the proper planting equipment, or feel they don’t have enough information to properly manage this new system. This tool may help them move to high-residue crop production systems.