Corn yield as affected by row pattern, plant density, and irrigation system

Row crops normally grown in Southeast USA are cotton (Gossypium hirsutum L.), corn (Zea mays L.), and peanut (Arachis hypogea L.) with a focus on the higher economic value for peanut. Peanut is typically planted using a twin-row pattern and purchasing a twin-row planter may not be cost effective unless used with other rotational crops. The objectives were to compare corn yield when planted in twin-rows, with two plant densities, at multiple locations, and irrigated with drip or sprinkler system. Corn was planted in single and twin-row patterns at 7.9 seeds/m (normal; 86,100 seeds/ha) and 4.9 seeds/m (half-normal; 53,600 seeds/ha) at multiple locations and cropping seasons. Irrigation systems consisted of subsurface drip (SSDI), shallow subsurface drip (S3DI) and overhead sprinkler. Single and twin-row with normal seeding rate had same yield across years, locations, or irrigation system 88% of the time. With drip irrigation only, twin-row half-normal seeding rate had the same yield as the single-row normal seeding rate 75% of the time and when factoring in seed savings had an economic benefit of $56/ha. The single-row half-normal seeding rate always had lower yield compared with other treatments. The S3DI irrigation system had greater yield than SSDI for both row patterns and seeding rates. Therefore, a twin-row planter purchased for peanut may be used to plant corn without yield reduction using normal seeding rates under either drip or sprinkler irrigation systems.