What’s Changing with Row Spacing?

As we dive deeper into planting factors and field conditions, like soil temperature and seeding rate, it’s easy to see how row spacing can provide another opportunity for farmers to optimize yields and profitability.

As you start to do your own research on optimum row spacing, you’ll likely find that a number of studies claim that narrow rows are the next big wave in maximizing corn yield potential.

But some of these articles and their field trials go back more than 20 years, while others share newer research, all touting the advantages of narrower rows for broadacre crops.

We asked ourselves, “Have farmers have been sticking to 30-inch rows for their corn setup versus going narrower?”

What has changed around corn row spacing?

Before 1940, most corn was planted in 40-44 inch rows to allow horses to get between the rows for cultivation.

But as herbicides came more available, farmers could move away from mechanical weed control and look at the advantages that could come from narrower crop rows.

As equipment evolved, agronomists began to study yield and efficiency benefits of adjusting row spacing. They found that narrower row spacing can offer plants even more access to light, water and nutrients.

Narrow rows can also lead to faster canopy closure, which means less lost solar energy, reduced soil moisture evaporation and less soil erosion. A closed canopy can mean better weed control, agronomically speaking.

Eventually, 30 inches became the row width of choice for many farmers and a standard width for headers and planters alike.

Among the millions of acres of aggregated, real-world farm production data contributed by network members in FBN, we analyzed row spacing in Illinois and Minnesota.

Below, you can see that 91 percent of growers in Illinois used a 30-inch row spacing last year. 

Likewise in Minnesota, most farmers are planting their corn in 30-inch rows, but 32 percent fewer than those in Illinois in 2017.

Studies have shown yield advantages in moving from 40- to 30-inch rows, but the move from 30- to 20-inch seems to be less conclusive, based on what farmer’s have said they are adopting.

For much of the country, results vary year over year, location by location, and simply don’t tell a consistent story. This could attest to there being multiple factors that play into how well changes in row spacing will impact each individual farm.

The data is in some ways more reliable, however, in the Northern Corn Belt. Their shorter growing season often leads to the selection of earlier maturing hybrids, which produce fewer leaves and require less time from emergence to silking.

This means less leaf area is available to intercept sunlight, as compared to fuller season hybrids.

Since agronomists have noted that so much of corn production is a light interception game, it makes sense that narrower rows using the same populations would allow for better use of available resources, thus allowing corn to more effectively reach its yield potential.

This could be one explanation for why more growers in Minnesota have been more willing to move to narrower corn row spacings, with 33 percent utilizing 22-inch rows in 2017.

This could also be because these narrower rows allow some farmers across this geography to use the same planter across several crops. For example, a 22-inch row width allows sugar beet growers to use the same planting equipment for sugar beets, corn and soybeans.

What should you consider with your corn row spacing?

Overall, while there is independent agronomic data and field trial results that indicate narrower corn rows can achieve higher yields, it’s unclear if this yield advantage alone outweighs the equipment and labor costs of changing your equipment setup.

Exploring whether or not to stay within the row width plan you are currently using versus changing to narrower rows should address overall profitability for the operation.

Combining and analyzing yield data from row spacing, alongsidesoil temperatures, seeding rate andplanting date can provide a more holistic look at what planting considerations and results have been successful for farmers in your state.

Planting data above is based on real-world farming data. I

nformation on seed hybrids has been aggregated across millions of acres of data 

from 2017. Maturity range includes 108-114 days in Illinois and 93-106 days in Minnesota. 

Seed Finder lets you see how each seed responds to planting conditions in your state - planting date, soil temperatures, seeding rate and row spacing are just a few.

Sources: https://crops.extension.iastate.edu/corn/production/management/planting/row.html https://www.extension.umn.edu/agriculture/corn/planting/narrow-row-corn-production/ http://www.dakotafarmer.com/story-case-narrow-row-corn-north-9-121047