Agronomic Decisions for Narrow Row Corn Production in the Eastern US Corn Belt.

There has been a resurgence in interest from growers in narrow row corn (Zea mays) hybrid production in recent years in the Eastern U.S. Corn Belt. However, agronomic recommendations with modern hybrids are limited for narrow row widths at higher seeding rates. Field research trials were conducted in 2015 and 2016 in Pennsylvania and Ohio to address the following research questions: i) do modern hybrids differ in their response to narrow (38-cm) and conventional (76-cm) row width?; ii) does narrow row production alter the optimum seeding rate?; and iii) is there a yield advantage for narrow row production? The first experiment (five site-years) evaluated hybrid response (four hybrids ranging in maturity from 105-d to 114-d) to row width. The second experiment (five site-years) focused on the interaction of row width and seeding rate (ranging from 86,500-111,200 plants/ha). Only one site-year demonstrated a row width by hybrid interaction for biomass production. The 105-d hybrid produced greater biomass in 38-cm rows compared to 76-cm rows, while the 106-d hybrid displayed the opposite trend at one site. Dry biomass production of the 105 and 106-d hybrids was less than the other hybrids at a different site. Only one site-year had a row width by hybrid interaction for grain yield. The 105-d hybrid produced greater grain yield in 76-cm rows than in 38-cm rows, whereas the 111-d hybrid produced greater grain yield in 38-cm rows compared to 76-cm rows. Four of five site-years resulted in yield and total biomass being maximized at 86,500 plants/ha regardless of row width. Only one site-year showed an interaction of seeding rate and row width on grain yield (optimal seeding rate was 98,800 and 111,200 plants/ha in 76-cm and 38-cm rows, respectively). Across hybrids or seeding rates, narrow rows resulted in greater grain yield and dry matter at four of the ten site-years and a grain yield reduction in one site-year. These research trials will be repeated to validate the observed results.