Thirty inch rows are most common in corn production in Pennsylvania. Thirty-inch rows average yields approximately 10 percent higher than 40-inch rows. Thirty-inch rows provide 4,356 more feet of row per acre than do 40-inch rows, and plants will be over 2 inches farther apart within the row (Table 1.4-9). Reducing the row spacing below 30 inches to 20 or 15 inches can result in higher yields as well. Penn State research has shown a 5 percent advantage for grain production and a 10 percent advantage for silage production in using 15-inch or 20-inch rows compared to 30-inch rows. This response appears most likely where N is not limiting.