Twin rows were a novelty many years ago. Back when farmers tried ridge-till, one central Midwestern farmer experimented with twin-row soybeans on ridges. That was his solution to staying o n ridges and narrowing the row spacing for soybeans to capture more sunlight- sort of having his won cake and eating it too.
More recently a northern Indiana farmer experimented with twin-rows. Since his corn planter was on 30-inch row spacing, he used RTK-GPS to simulate 5-inch twin rows, with a 25-inch gap in the middle. He upped the population for that corn, but only slightly compared to his regular corn. Final population on the twin-row corn wound up in the mid-30,000 plants per acre range. In the end, one hybrid in his 100-acre plus 'test' plot field yielded considerably more on twin rows vs. 30-inch rows, definitely enough to pay for the practice. And that was at $2 corn. However, the yield boost for the second hybrid wasn't as high, and at that time it was nearly a wash on that particular hybrid. Since then the farmer switched to fall strip-till, and decided twin rows wasn't feasible in his operation using that system. Otherwise, he likely would have looked at twin rows again.
While twin-rows and narrow rows may still be miniscule in percentage of use, except perhaps in the northern tier of the Corn Belt, the novelty stage is over. Those who have made some narrower-row pattern work believe in it. One of the more common patterns is 20-inches. Some like it because they can do soybeans in the same row pattern. And while there are agronomists who might argue they're not obtaining absolute best yield for soybeans in 20-inch rows vs. 15-inch or narrower, they believe it's an advantage vs. leaving soybeans in 30-inch rows.
Dave Nanda, consultant for Corn Illustrated and President of Bird Hybrids, LLC., Tiffin, Ohio, believes interest in some planting configuration for corn narrower than 30-inch rows will continue to increase, even further south in the Corn Belt than where it is somewhat popular today. He sees it as a method farmers can use to capture more sunlight, and sunlight is the free power source that drives efficiency and maximum economic yields in corn.
Corn Illustrated plots will include a row-width comparison this year, assuming everything works out as planned. Nanda is also considering hand-planting a small block to achieve equidistant planting, just for demonstration purposes. Research conducted at Stewart Seeds a few years ago pointed toward a definite advantage in yield for certain hybrids in narrower rows, particularly in 10-inch rows. As you narrow up the row spacing and spread spacing between plants within the row, you move closer toward equidistant spacing.
Once you achieve nearly equidistant spacing, you have maximized the field's ability to capture the maxi9mum amount of sunlight per acre, Nanda says. Since sunlight is a main driver in photosynthesis, the process that produces sugars and energy for the plant, you've also enhanced the production capacity of your 'on-farm' factory in the field, he concludes.