Vertical tillage is tillage
Just one pass with a vertical tillage tool can improve planting conditions while still maintaining surface residue. However, aggressive use of the tools, or using it on more than one pass, will decrease the conservation benefits
Vertical tillage tool utilization prior to planting has been increasing. The need to manage corn stalks in a no-till system is one reason. Others include the incorporation of manure, lime or fertilizer into the soil as well as conditioning the seedbed prior to planting. But can this tool improve planting conditions and provide the conservation benefits of no-till?
University of Wisconsin’s Kevan Klingberg and Dennis Frame, in cooperation with Discovery Farms’ Curt Weisenbeck, looked at the impact of shallow vertical tillage on soil disturbance and crop residue. They found that just one pass with a vertical tillage tool will leave 70 to 80 percent of previous corn residue in place and 80 percent of last year’s corn roots. More aggressive tillage may eject more corn roots and leave more soil exposed. (Understanding Shallow Vertical Tillage Use and Soil Disturbance Fall 2011.) The tools evaluated in the study were equipped with wavy or straight coulters mounted on straight tool bars. This is a less aggressive setup than the concave disks mounted an angled tool bars. The authors concluded that “conservative and shallow are key phrases when considering the use of these implements on cropland with high soil loss potential.”
Although these tools are often used just ahead of planting to improve the seedbed, they should not be used on wet soil. DeAnn Presley, soil specialist with K-State Research and Extension says that vertical tillage should only be used when the soil is dry enough to shatter; otherwise, it may create shallow compaction. (K-State Agronomist Discusses Vertical Tillage – What It Is and How it Works.)
A single pass will size corn stalk residue to about 12-inch pieces and bury pieces smaller than 2 inches. This sizing allows better operation of planting equipment and improves seed placement. Studies in Michigan in 2010 and 2011 showed an increase in soybean yield in 2010 when the Case Turbo Till was used, but when results were combined over two years, there was no significant difference. It was also observed that the incidence of white mold was greater in the vertical tillage treatment than in the no-till at one field site. (A summary of tillage effects on soybean yields in Michigan 2010 and 2011.)
It is always a good idea to talk with the local NRCS office staff to be certain changes in your tillage system are an acceptable practice within a particular Farm Bill Conservation program. Vertical tillage is typically referred to as a mulch tillage practice.
Just one pass can maintain conservation benefits of residue and size residue so that it is more manageable at planting time. However, it is not clear if the improved planting conditions will result in an increase in yield.