U of M research helps growers narrow yield gap for corn
ST. PAUL -- With high production costs for corn, growers must focus their management on factors that have the greatest potential to increase yield. Prerequisites for high-yield corn include favorable weather and adequate levels of drainage, soil fertility and pest management.
Recent research by University of Minnesota Extension has focused on discovering how additional agronomic factors could be modified to narrow the gap between actual and potential corn yields. This research found that decisions related to hybrid selection are among the most important.
In corn hybrid trials from 2007 to 2010 near Rochester, with 98 to 153 hybrids evaluated each year, the highest yielding hybrid yielded 37 to 64 percent more than the lowest yielding hybrid. Hybrid relative maturity was less important in these trials, with hybrids of 98- to 102-day relative maturity yielding just 2 percent more than those in the 93- to 97-day range.
Another important factor influencing corn yield is crop rotation. In long-term experiments conducted by land-grant universities in Wisconsin and Indiana, corn yielded 5 to 19 percent higher when following soybean or alfalfa rather than corn, with the smallest yield increases occurring in years with favorable weather and high yields.
In these trials, conservation tillage systems such as strip-till and disk-till worked well on silt loam soils when corn followed soybean or alfalfa, but a more aggressive tillage system was needed to optimize yield of corn following corn, especially on heavy soils.
Uniform stand establishment is also critical for corn, as research at Lamberton found that a plant just one leaf stage behind early in the season yielded 20 percent less. Additional research by University of Minnesota Extension that was funded by the Minnesota Corn Growers Association found that a delay in planting from late April to mid-May reduced corn yield by 2 percent. However, planting in late May rather than late April reduced yield by 15 percent.
In these trials, increasing the final stand from 30,000 to 34,000 plants per acre increased corn yield by 1 to 2 percent, while planting in narrow or twin rows increased yield by 0 to 3 percent. In northwestern Minnesota, however, yield increases with high plant populations and narrow rows have been much greater.
These results demonstrate that the easiest options for increasing corn yield are related to hybrid selection, crop rotation, tillage system and uniform emergence. For more educational resources on corn production in Minnesota, visit University of Minnesota Extension's corn website at www.extension.
Jeff Coulter is a corn agronomist with University of Minnesota Extension.