Corn (Zea maysL.) was grown for five consecutive years on Cecil fine sandy loam to measure the effects of irrigation and fertilization on leaf composition, yields, and on the changes in available K in the soil. Plant nutrients consisting of 0, 56, 140, 224 and 280 kg N/ha: 0, 15, 37.5, 60 and 75 kg P/ha, and 0, 28, 70, 112 and 140 kg K/ha were applied in a central composite rotatable design in each of the five years. All plant residue was removed each year when the corn was harvested and the plots were seeded without fertilization to rye each year as a cover crop. One‐half of the experiment was irrigated when there was a 50% depletion of available soil moisture in the 0‐ to 45‐cm soil depth.