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Emerson D. Nafziger
Professor of Crop Production Extension
Department of Crop Sciences
(217) 333-4424; email@example.com
Twin Rows For Corn
Twin-row corn is not a new idea, but this technique has received renewed interest in the past few years, with some reports of substantial yield increases. The attraction of this planting geometry is that it captures some of the narrow-row yield advantage that some believe exists, while at the same time it allows many field operations, including spraying and harvest, to be done using existing equipment.
We do not have yield data from recent studies in Illinois, but work in other states and in Ontario have shown mixed results, with either no yield change due to twin-row configurations or small increases or decreases, most statistically not significant (meaning that the results were not definite) or small enough to make researchers question the economics of this practice. Some producers and researchers have reported higher yields, though, and some also point to better standability in twin row corn.
The only new equipment needed for twin rows is the planter mechanism. The Great Plains and ATI equipment companies, both located in Kansas, offer twin row planting mechanisms. Great Plains currently mounts their units on drill frames, and they also make drills capable of singulating corn seeds, which can be configured to plant any row spacing in multiples of 7.5 inches. ATI’s Monosem planters are of European design, and are also used for vegetables, beets, cotton, and peanut.
The study in Urbana this year was planted on May 10. We planted two populations in twin rows, then three plots of 30-inch rows and one of 15-inch rows in each replication. After emergence, the twin-row populations were counted, and the 30-inch rows thinned to the same two populations - 27,200 and 34,500 per acre - with the third, 30-inch row plot thinned to 19,800 to form an equally-spaced range. The 15-inch rows were thinned 34,500 as well. Because we have not found consistently higher yields in 15-inch rows compared to 30-inch rows in studies with equal plant populations in previous work in Illinois, we see little reason to expect large yield responses from twin rows. In terms of crop appearance, however, twin rows and 15-inch rows seem to be covering the soil faster early in the season, as the following set of photos from this study shows:
Light measurements under the canopy showed that light interception on June 20, when plants were in stage V10 and about 3 ft. tall, was slightly higher for twin rows and for 15-inch rows than for 30-inch rows at the same populations. This is shown in the following figure. If these differences persist into grainfilling, then we might see some yield response as well under this year’s conditions. We’ll only know that when the combine rolls, of course.
As with work on narrow rows, it is important that we make row spacing comparisons at the same plant populations. This will allow us not only to make fair comparisons, but also to see if different row arrangements might call for different plant populations.