University of Kentucky – ASA San Antonio TX 2011 Row Width Effect on Corn Yield in Kentucky Grant A. Mackey *, Chelsea C. McFarland, Chad Lee Field plots were placed across the state of Kentucky to study the interaction between row width and corn yield. The primary objectives were to test if 1) narrower rows increase yield and 2) higher plant populations increase yield. Three hybrids (A6533VT3, DKC62-97, P1480HR) were randomized in a split-split plot design with row widths (76, 38 cm or twin) as the split and plant density (75000, 87500, 100000, 112500 plants ha-1) as the split-split plot. Three replications of the main plot (hybrid) were seeded at three locations in Kentucky (Princeton, Elizabethtown, and Lexington). Biomass yield and harvest index were measured by hand-harvesting samples after physiological maturity. Grain yields were machine-harvested (Wintersteiger) from the center rows and yields were adjusted to 15% grain moisture.