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ARS Home » Southeast Area » Raleigh, North Carolina » Soybean and Nitrogen Fixation Research » Research » Publications at this Location » Publication #389933

Research Project: Exploiting Genetic Diversity through Genomics, Plant Physiology, and Plant Breeding to Increase Competitiveness of U.S. Soybeans in Global Markets

Location: Soybean and Nitrogen Fixation Research

Title: Response of maize, cotton, and soybean to increased crop density in heterogeneous planting arrangements

item ETHRIDGE, SANDRA - North Carolina State University
item Locke, Anna
item EVERMAN, WESLEY - North Carolina State University
item JORDAN, DAVID - North Carolina State University
item LEON, RAMON - North Carolina State University

Submitted to: Agronomy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/19/2022
Publication Date: 5/23/2022
Citation: Ethridge, S.R., Locke, A.M., Everman, W.J., Jordan, D.L., Leon, R.G. 2022. Response of maize, cotton, and soybean to increased crop density in heterogeneous planting arrangements. Agronomy.

Interpretive Summary: Planting density and arrangements can be tools for farmers to suppress weeds. However, there has to be a balance between weed suppression and not over-planting the crop. This study tested four different heterogenous planting arrangements, to see if heterogenous planting can help suppress weeds without high density in all rows. Corn and cotton growth was not affected by the different planting arrangements, but soybean growth adjusted to the different arrangements, with higher biomass in some planting arrangements than in others. Yield wasn’t affected by planting arrangement in any of the three crops. This indicates that heterogenous planting arrangements might not be needed for weed suppression with high-density planting, but there may be other benefits to the heterogenous planting arrangements in soybean.

Technical Abstract: The reduction of row spacing and increase of crop population density are important tools for crop weed suppression. For this strategy to be effective, the crop population should not create intraspecific crop competition above the interference levels exerted. Thus, planting arrangements that increase light interception throughout the canopy without increasing row spacing might be needed to maintain yield. In this study, heterogeneous planting arrangements on evenly spaced rows were analyzed for corn (Zea mays L.), cotton (Gossypium hirsutum L.), and soybean (Glycine max L. Merr.). Each crop had four planting arrangements: 1) normal density in all rows, considered the control, 2) doubled density in all rows, 3) a sequential arrangement of normal and tripled densities (each in every other row; NTNT), and 4) normal-tripled-tripled-normal (NTTN). Corn and cotton did not exhibit changes in growth and architecture when comparing uniform and variable planting arrangements. Soybeans were more adaptable and were able to increase biomass production by 43.9% to 44.7% by taking advantage of variable arrangements. None of the crops showed differences in yield due to planting arrangement, so the use of rows with different densities might not be needed to when using high densities to reduce weed pressure, as part of a robust integrated weed management program. However, in crops with more plasticity, such as soybean, the use of heterogeneous planting arrangements might have potential to increase biomass production and associated ecosystem services.