Is switching to narrow row corn the right choice for you?

A summary of research conducted in Michigan and surrounding states will tell you whether corn performance will increase or decrease in narrower rows.

A common question I get from farmers concerns switching from 30-inch to narrower row spacing. Farmers are curious about just how much their yields may improve if they make the switch. The following are research findings from Michigan and other Midwestern states that give information on corn performance in narrow rows.

Porter et. al. (1997) looked at corn planted at 30-inch and 20-inch row spacing at three locations over three years (1992-1994) in Minnesota. The range in response was anywhere from a 2 percent loss in 20-inch rows to a 15 percent increase in 20-inch rows. When all sites were averaged over the three years, yields increased 7 to 8 percent when 20-inch rows were compared to 30-inch rows.

They also found that

  • Corn response to plant population was similar for both 20- and 30-inch rows, and

  • Hybrids that performed well in 30-inch rows also performed well in narrow rows.

A group of Minnesota Extension educators report that once the investment to switch equipment over to narrow rows is made, machinery costs were virtually equal or less for growers planting corn in 19- to 25-inch rows when compared to 26- to 32-inch rows.

To review these studies, go to Minnesota Extension’s Narrow-Row Corn Production in Minnesota website.

Bob Nielsen, corn agronomist at Purdue University, conducted studies at three locations comparing 15- and 30-inch row spacing performance from 1984-1986. His results ranged from a 3.1 percent loss to an 8.2 percent increase with narrow rows. The average increase was 2.7 percent.

In surveying studies from around the Corn Belt, Nielsen discovered that increase in yield from narrow rows has been relatively small in the central Corn Belt, but that growers in the northern Corn Belt (states like Minnesota and Michigan) have the greatest probability of success with narrower row corn production.

To read more about Nielsen’s findings, see Perspectives on Narrow Row Spacings for Corn (Less Than 30 inches).

Michigan State University’s own Kurt Thelen conducted research on narrow row corn. In 2000 and 2001, Thelen conducted studies on corn grown in course-textured and fine-textured soils in Monroe and Clinton counties. He found that the yield advantage was greater for narrow rows on the coarser textured soils, as compared to the finer textured soils.

Thelen also looked at 840 comparisons of 15- and 30-inch row corn trials conducted between 1999 and 2001. He reported that when growing conditions were such that yields obtained in wide rows were favorable, the resulting yields obtained by narrowing the rows were relatively low. Or, to put another way, narrow rows increase yield more when growing conditions are worse.

To read Thelen’s complete study, see Interaction Between Row Spacing and Yield: Why it Works.

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