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

Authors: Sorensen, Ronald - Ron; Lamb, Marshall; Butts, Christopher - Chris

Submitted to: Journal of Crop Improvement
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/11/2021
Publication Date: 10/12/2021
Citation: Sorensen, R.B., Lamb, M.C., Butts, C.L. 2021. Corn yield as affected by row pattern, plant density, and irrigation system. Journal of Crop Improvement. https://doi.org/10.1080/15427528.2021.1980754.
DOI: https://doi.org/10.1080/15427528.2021.1980754

Interpretive Summary: Corn is grown on about 540,000 acres in the tri-state area of Alabama, Florida, and Georgia. Current crops grown in rotation with corn include peanut, cotton, soybean, sorghum, and wheat. A typical cropping sequence would be cotton, corn, and peanut. The current recommendation for peanut is to plant in a twin-row pattern for greater yield and grade. Purchasing a twin-row planter just for peanut may not be cost effective unless it could be used with other rotational crops. Planting corn in a twin-row pattern would increase distance between individual plants. However, depending on climate, soils series, rotation, irrigation rates, plant population, or other management treatments, the planting of twin rows had a positive, negative, or neutral response to corn yield. Therefore, it is important to have research data in local areas as a guide. Irrigation systems apply water to the soil to reduce the effects of drought during the growing season. Also, the type of irrigation system, either drip or sprinkler irrigation, may influence yield of agricultural crops. There does not seem to be an effect of row pattern, i.e., twin-row, on the yield of corn, depending on specific conditions. However, little research was done comparing SSDI, S3DI or sprinkler systems. In addition, most research increased the rate of plant population or slightly lower than recommendation, but none had plant populations at half the recommended rate. Therefore, the objectives of this research were to document corn yield when: 1) planted in twin-rows, 2) plant densities at recommended and half the recommended rates, and 3) with various irrigation systems (sprinkler and drip). Research was conducted at three locations using subsurface and shallow subsurface drip irrigation (SSDI and S3DI, respectively) and sprinkler irrigation. Research treatments were similar across all sites, soil series, and irrigation systems. All plots had the same width of 18-ft or 6 crop rows. There were 6-row patterns of single and twin-row. The single rows were space 36-inches apart while the twin-row pattern was centered on 36-inch row. All crops were planted with a 6-row double disk opener vacuum planter at recommended seeding depth. Twin-row planting was accomplished using GPS by shifting the tractor/planter 3-inches to the left and right of a 36-inch center, to get a 6-inch middle between the twin-rows. There were two plant populations of 2.4 (normal) and 1.5 (half normal) seeds/ft. Soil samples were taken to determine any fertilizer deficiencies and recommendations for the upcoming crop. Fertilizer application applied the minimum amount of nitrogen that could be used with the type of fertilizer available from the local dealers. Single and twin row with normal seed rate had same yield across years, locations, or irrigation system 88% of the time. Twin row half normal seeding rate had the same yield as the single row normal seeding rate 75% of the time across all test locations and irrigation system. The single row half normal seeding rate had lower yield across all years and with all drip irrigation systems but not with the sprinkler system. From an economic perspective, half normal seeding rate tended to have lower yields especially with single row orientation and with drip irrigation which lost an average $-262/ha even after factoring in seed savings. Drip irrigation with twin row half normal seeding rate had lower yields 16% of the time but when factoring in seed savings had an economic benefit of $56/ha ranging from $-29 to $188/ha depending on location. This research indicates no yield difference when planting with either single or twin row orientation when using recommended seeding rates. However, if seeding rates are reduced, it is recommended to plant in a twin row orientation to spread plants out and minimize yield reduction such that seed savings will cover the loss

Technical Abstract: 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.