Strip-till corn not only performs well compared to other tillage systems in both cool and dry years, but also maintains excellent residue on the surface of the soil, according to University of Minnesota Extension research.
Using strip-till and other tillage equipment owned by farmers, the University of Minnesota Extension compared four tillage systems for corn following soybeans on farm fields in 2004 and 2005. Corn grain yields were affected significantly by tillage treatments at six of the 10 sites in the cool growing season of 2004, according to Jodi DeJong-Hughes, University of Minnesota Extension strip-till expert and Jeffrey Vetsch, University of Minnesota Extension soil scientist.
Averaged across sites with the four similar tillage treatments, corn grain yields for each tillage system were:
strip-till, 174.6 bushels per acre
no -till with disk openers, 167.8 bushels per acre
no-till with hoe openers, 174.2 bushels per acre
chisel plow with hoe openers, 177.4 bushels per acre.
The strip-tilled fields had an average of 55% residue cover and the one-pass system had 30% residue cover.
In the warmer-than-normal 2005 growing season, corn yields were affected significantly by tillage treatments at only one of nine sites.
Strip-till, 202.2 bushels per acre;
no till with disk openers, 195.8 bushels per acre
no -till with hoe openers, 196.5 bushels per acre
chisel plow with hoe openers, 200.5 bushels per acre.
The trials in 2005 demonstrated that strip-till and no-till produced excellent corn yields, while maintaining adequate residue cover to protect the soil from erosion.
Continuous-corn systems produce higher residue levels requiring more precise management. The University of Minnesota began research in southern Minnesota in 2006 to study the effects of high-residue systems during several years. This research used moldboard plowing, disc ripping and strip-till on a continuous-corn field to study the effects of residue placement on seedling emergence, soil temperature and grain yield. The soil at the site is a heavy clay loam, with poor internal drainage and no tile drainage.
Strip-tilling left almost 50% residue, while moldboard plowing left 10% residue cover and disc ripping left 34%. In 2006, the yields were similar for all three tillage systems (Table 4).
In the fall of 2007, six more field trials were established using the same procedures described above. Researchers will continue to evaluate the residue buildup and its effects on yield.
Research that NDSU conducted in 2007 indicated similar corn yields with strip-till compared with conventional till and an advantage with strip-till yield compared with no-till. At NDSU’s research site near Carrington, corn was grown in 30-inch rows on a loam soil with adequate soil moisture during the reproductive stages. Plant emergence and silking were delayed 1 to 3 days with no-till, compared with strip-till. Corn was grown in 22-inch rows at the Red River Valley sites. At Fargo, the trial was conducted on a silty-clay loam soil. Nearly continuous rain from planting until mid-June reduced soil nitrogen and corn yields.
Table 4. Corn yields from various tillage systems in southern Minnesota.
Table 5. Corn yield with various tillage systems, 2007.
———————————— Corn Yields - bu/acre ————————————
1 Previous crop: Carrington = spring wheat; Fargo = sugar beets; Prosper and Moorhead = soybeans. 2 Not a significant yield difference.