Corn Row Spacing

Key Points

  • Narrowing the corn row may be one way to help accomplish increased returns.

  • Regardless of row spacing, the most important decision to help maximize yield potential is selecting the best-adapted product(s) for the area and for the planned planting population.

  • Narrower rows can allow for faster canopy closure, reduced evaporation, and help minimize plant competition.

  • Twin-row configurations are a consideration that can allow for equidistant plant spacing.

  • Twin-rows have been more consistent in northern states.

Row Spacing Configurations

Planting corn into rows narrower than 30-inches has been an increasing practice because of the potential for increasing yield, increasing profitability, and maximizing equipment efficiency. The cost to produce a bushel of corn in relationship to its selling price helps drive research by farmers, universities, and Monsanto to find ways to increase on-farm returns. Narrowing the corn row may be one way to help accomplish increased returns. Several narrow-row configurations being tested and utilized by farmers include more traditional 15- and 20-inch row configurations and twin-row designs (Figure 1).

Twin-row configurations have 30- or 38-inch row centers flanked by two rows that are about 7.5 inches and 11.1 inches apart in non-synchronized and synchronized formations, respectively (Figure 2).The synchronized formation creates a uniform triangular spacing. The benefits of twin-row spacing are similar to those of other narrow row spacings.

Benefits of narrow row spacings (< 22.5-inches) can include: 

  • Minimization of competition among plants for water, nutrients, and light because plants are equally spaced.2 The effects of plant competition become important when stress factors are present. 
  • Faster canopy closure and more shading, which can help manage weeds.
  • Earlier soil shading can help reduce the loss of soil water through evaporation.
  • Planting equipment can be potentially used for multiple crops. 
  • Potential for increased yield.

Disadvantages of narrow row spacing can include: 

  • Increased compaction from farm equipment when planting in narrow rows.5 
  • Mechanical cultivation and postemergence herbicide applications may be more difficult in narrow rows.3 
  • Extra expenses associated with switching to narrow rows, which can include: a new or modified planter, rims, and tires, increased rates of insecticide and starter fertilizer.3
Figure 1. Row configurations of 30-inch row (left), 20-inch row (center), and twin-row (right), which is typically based on 38- or 30-inch centers.

University Research

Corn grown in 15- or 20-inch rows demonstrated a yield advantage of 7 to 10% when compared to 30-inch rows according to university research in Minnesota, Wisconsin, and Michigan.2,4 The advantage has been attributed to the required use of earlier maturing corn products, which generally are shorter, have fewer leaves, require less time from emergence to silking, and have less leaf area for sunlight interception.2

University research in the Central Corn Belt has shown a lower and more variable result for narrow rows because of year-to-year variability. Purdue University reported an average yield increase of 2.7% in favor of 15-inch rows over 30-inch rows in a three year, three location study.3However, year-to-year data showed the average yields ranging from -3.1% to 8.2% for 15-inch rows compared to 30-inch rows. In a three year study, Iowa State University reported no yield differences for narrow rows at all locations and corn products, while other research has reported yield increases in the Central Corn Belt up to 5%.3,5

According to Penn State University studies from 1994-1996, silage producers may benefit from narrower rows and increased population based on an average 11.2% in silage yield.6 Cornell University information showed an increase of about 5% in silage yield when silage was produced from 15-inch rows.6

Monsanto Research

Research from 2007 to 2009 at the Monsanto Learning Center at Gothenburg, NE demonstrated variable results for single- and twin-row configurations because of the environmental conditions of each growing season. The twin-row configuration in 2007 and 2008 outyielded the single-row configuration at all populations, while the single-row outyielded twin-row configurations at all populations in 2009. In a 2014 Monsanto Learning Center study at Monmouth, IL, twin-rows were the highest yielding row configuration; however, past studies have shown inconsistency.

A non-replicated, one-year demonstration conducted at the Monsanto Learning Center at Scott, MS compared a 114 relative maturity (RM) corn product and a 116 RM corn product at 30- and 38-inch single-row spacings and 38-inch twin-row spacings. The study indicated that the 30-inch single rows had the highest yield potential, but farmers can increase yield potential with narrow rows if a corn product is selected that responds to higher plant populations. The contrasting results of these studies indicate the variable nature of yields from year-to-year in different row spacings.  

Figure 2. Non-synchronized twin-row formation (left). Synchronized formation (right).

Corn Row Spacing

Regardless of row spacing, the most important decision to help maximize yield potential is selecting the best-adapted product(s) for the area and for the planned planting population. Some corn products may be more susceptible to lodging when planted in narrow rows and/or at higher populations. Contact your Channel® Brand Representative or visit www.channel.com for product information.

Sources:

1Monmouth, IL Learning Center Summary, 2013. Effects of twin row configuration on corn yield. Monsanto Technology Development. The Learning Center at Monmouth, IL Demonstration Report.  

Stahl. L., Coulter, J., and Bau, D. 2009. Narrow row corn production in Minnesota. University of Minnesota Extension. Publication No. M1266 2009. 

 3 Nielsen, R.L. 1997. Perspectives on narrow row spacings for corn (less than 30 inches). Purdue University. Publication No. AGRY-96-17.  

4 Laurer, J. 1996. Planting corn in rows narrower than 30-inches. University of Wisconsin. Agronomy Advice. Publication No. Field Crops 28.423-8. 

 5  Pecinovsky, K.T., Benson, G.O., and Farnham, D.E. 2002. Corn row spacing, plant density, and maturity effects. Iowa State University. Northern Research and Demonstration Farm. Publication No. ISRF02-13.  

6 Roth, G. 1997. Potential of narrow row corn production in Pennsylvania. Agronomy Facts 52. Penn State University. Other sources: Monmouth, IL Learning Center Summary, 2014. Effects of corn product, population, and row width on yield. Monsanto Technology Development. The Learning Center at Monmouth, IL Demonstration Report.   Gothenburg, NE Learning Center Summary. 2010. Corn row spacing and equidistant planting in 2010. Monsanto Technology Development. The Learning Center at Gothenburg, NE Demonstration Report.  Scott, MS Learning Center Summary. 2012. Evaluation of three corn row configurations. Monsanto Technology Development. The Learning Center at Scott, MS Demonstration Report. Web sources verified 11/2/15. 130922070109

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