INTRODUCTION AND OBJECTIVES Growers are continually striving to increase corn yield and profits. Planting corn in narrow rows is one potential way to do this. University of Minnesota research in southern and central Minnesota has shown that corn yields can be increased 7 to 9% by planting in 20-inch rows compared to 30 inch rows, but increases have not been consistently observed (1). It is also hypothesized that populations that optimize yields are greater in narrow rows than in 30-inch rows. Results from University of Minnesota trials conducted in northwestern MN from 2009-2011 indicated that yields were optimized at higher populations in narrow rows than in 30-inch rows (2).
In a twin-row corn system, which is a variation of narrow-row corn, corn is planted in row pairs six to eight inches apart with 30 inches separating the center of the row pairs. Plant arrangement is more spread out in twin rows compared to 30-inch rows at the same planting population, because the same number of seeds would be planted in two adjacent rows in a twin-row system versus in one row in a 30-inch system. A major advantage of planting corn in twin row rows compared to 15- or 22- inch rows is that beyond modifications to the planter, no additional major equipment modifications are needed. For example, a standard combine head can be used to harvest the crop, and narrow row tires, which can be very costly compared to standard tires, are not essential.
Trials conducted in more southern states indicate that yields may be increased by planting corn in twin rows compared to 30-inch rows, although results have been inconsistent (3). Anecdotal reports from growers in planting corn in twin rows in southern Minnesota indicate there is potential to increase yields by planting corn in twin rows compared to 30-inch rows. Little research information exists in Minnesota, however, regarding the effects of planting corn in twin-rows. This study was initiated in 2010 at two on-farm locations in southern Minnesota to determine 1) If row width (30-inch vs. 22-/8-inch twin rows) influences corn grain yield, harvest moisture, stalk lodging, and economic return and 2) If corn planted in twin-rows has a greater response to an increased seeding rate than corn planted in 30-inch