Effects of Plant Population, Row Spacing, and Relative Maturity on Dryland Corn in the Northern Plains. I. Corn Forage and Grain Yield1

Abstract

AbstractNarrow rows or equidistant planting of corn (Zea mays L.) has been beneficial in the Corn Belt. The concepts were evaluated at Mandan, N. D., to determine their influence under dryland conditions and in combinations with early‐maturing varieties which partially evade late season drought. The 68 and 85‐day relative maturity hybrids were grown at plant populations of 20,000; 30,000; 40,000; 60,000 and 74,000 plants/ha in 50 and 100‐cm spaced rows for 3 years. In 1968, a “wet” year, row spacing and maturity class significantly affected dry matter production, but only population influenced grain yield. Plant population and maturity class significantly affected grain yield in 1969 and 1970, but only population influenced dry matter in 1969. Interactions were not significant. Later‐maturing corn averaged 12% greater forage yield, but early‐maturing corn produced 19% more grain. Average grain yields increased from 2,600 to 3,070; 3,090; 2,960; and 2,680 kg/ha with progressive increases in population. Grain yield for 50 and 100‐cm rows averaged 2,890 and 2,870 kg/ha, respectively. Number of barren stalks increased and ear weight decreased with increased population. Optimum plant population for grain and forage ranged from 30,000 to 40,000 plants/ha.