Now is a great time to consider modifications to your corn production system for 2010. A key step to higher corn yields may be narrow rows (narrower than 30 inches). Planting corn in narrow rows increases the within-row distance between plants, which in theory helps minimize competition among plants for water, nutrients, and light. This is particularly true in the northern Corn Belt, where the shorter growing season and cooler air temperatures can limit crop yield potential. For corn growers contemplating narrow rows, consider the following.
Increased Grain Yield
Figure 1. Average yield for southern Minnesota growers planting corn in 19- to 25-inch rows or 26- to 32-inch rows, as reported in the FINBIN Farm Financial Database. An average of 145 and 1,457 fields were represented in the 19- to 25-inch and 26- to 32-inch row categories, respectively.
Figure 2. Average yield for west-central Minnesota growers planting corn in 19- to 25-inch rows or 26- to 32-inch rows, as reported in the FINBIN Farm Financial Database. An average of 46 and 180 fields were represented in the 19- to 25-inch and 26- to 32-inch row categories, respectively.
Figure 3. Average yield for northwest Minnesota growers planting corn in 19- to 25-inch rows or 26- to 32-inch rows, as reported in the FINBIN Farm Financial Database. An average of 33 and 19 fields were represented in the 19- to 25-inch and the 26- to 32-inch row categories, respectively.
An analysis of farm financial data generated from growers throughout Minnesota provides an indication of corn performance for narrow rows when compared to 30-inch rows. This information was self reported by growers utilizing farm business management associations with the University of Minnesota and the Minnesota State Colleges and Universities System, and is stored in the FINBIN financial database. When reporting information, growers were asked to select a row width category for each field. Average corn yields for these row width categories are listed below for southern (includes the southwest, south-central, and southeast regions), west-central, and northwest Minnesota (Figures 1-3).
In southern Minnesota, corn grain yield was greater in 19- to 25-inch rows than in 26- to 32-inch rows in two of five years from 2003 to 2007, but was equal for the five-year average (Figure 1). In west-central Minnesota, corn yield was consistently 1 to 8% greater in 19- to 25-inch rows than in 26- to 32-inch rows from 2003 to 2007, resulting in an average advantage of 7 bu/A (Figure 2). From 2003 to 2007, yield in northwest Minnesota was greater in 19- to 25- inch rows than in 26- to 32-inch rows by an average of 18 bu/A. Although these results should be interpreted with caution because they do not represent direct comparisons between row widths, they do indicate that there is a greater potential for yield increase with narrow rows as one moves north.
With generous support from the Minnesota Corn Growers Association, Pioneer, and Monsanto, we will be comparing grain yield and agronomic responses of various hybrids in 20- or 22-inch rows versus 30-inch rows at multiple plant populations at Lamberton, Morris, and Waseca, MN over the next two years, and at Moorhead and Crookston, MN over the next three years.
No Changes in Optimum Plant Population or Hybrid Selection
Many studies have evaluated whether or not plant population should be increased when switching to narrow-row corn. Yield has typically been optimized at a similar plant population regardless of row spacing (Figures 4 and 5). In addition, there is little evidence to indicate that row width should influence decisions regarding hybrid selection. The majority of the research conducted in the northern Corn Belt has found no interaction between row width and hybrid. In other words, hybrids that performed well in 30-inch rows also performed well in narrow rows.
No Change in Grain Moisture at Harvest
Research conducted by the University of Minnesota from 2005 to 2008 in southern Minnesota found that grain moisture at harvest is not significantly influenced by row width (Table 1). In these trials, differences in harvest moisture between 20- and 30-inch rows were never greater than one percentage point.
Table 1. Corn grain moisture at harvest for a population of 32,000 plants/A by row width.
Increased Silage Yield Without a Reduction in Silage Quality
An increase in silage yield has been consistently reported in the northern U.S. for corn grown in 15- or 20-inch rows when compared to 30-inch rows (Table 2). Reported increases in silage yield due to narrow rows have ranged from 4 to 9%. Row width, however, does not influence silage quality or the optimum plant population with regard to silage yield and quality.
Table 2. Response of corn silage yield to row width in various university trials.
A new in-depth fact sheet on narrow-row corn production in Minnesota is now available. Additional information on corn production from the University of Minnesota is available on our corn production website.