Northwest and Allee Research and Demonstration Farm
As corn production practices improve, row widths decrease. Although most producers plant in 30-in. rows, more and more acres are being planted to narrower row widths (15 in. to 20 in.). In addition, plant populations continue to increase every year with the introduction of more stress-tolerant hybrids. Wider row widths force more plants into a concentrated area, whereas narrower rows allow more equidistant spacing of plants.
Iowa State University
Marlay, Stephanie; Elmore, Roger W.; and Abendroth, Lori, "Twin Row vs. Single Row Spacing at Variable Seeding Rates" (2010). Iowa State Research Farm Progress Reports. 426.