By Laura Lindsey, Adapted from C.O.R.N. 2021-04, Ohio State University Extension
With funding from the United Soybean Board, soybean agronomists across the U.S. came together to summarize soybean row width, planting date, and seeding rate research trials. (Ohio-specific research trials were funded by Ohio Soybean Council.) Here’s what we found:
Row width Soybean row width varies across the U.S. In Ohio, most farmers plant soybean in 7.5-, 15-, or 30-inch row widths. Across the U.S., narrow rows (7- to 15-inch) out-yielded wide rows (≥ 30 inches) 69% of the time. Narrow rows tend to out-yield wide rows due to earlier canopy closure which facilitates light interception and drives photosynthesis. For the full report on row spacing: https://soybeanresearchinfo.com/wp-content/uploads/2021/02/FINAL-2700-002-20-Row-Spacing_Science-for-Success-Dec-22_v1.pdf
The date of planting has more effect on soybean grain yield than any other production practice. In many instances, this means planting soybean as early as field conditions allow, but generally at or after the Risk Management Agency (RMA) replant crop insurance dates begin. In Ohio, we estimate a yield reduction of 8% when planting soybean on May 31 compared to May 1. Although, this reduction can vary (or become minimal) depending on rainfall during the R3 to R5 growth stage. For the full report on planting date: https://soybeanresearchinfo.com/wp-content/uploads/2021/02/FINAL-2700-002-20-Planting-Date_Science-for-Success_Dec-22_v3.pdf
Soybean plants respond to their environment through branching and can produce maximum yields at relatively low plant densities (plants per acre). For normal planting dates in the Midwest, generally 100,000 to 125,00 plants per acre is required to achieve maximum yield. (A higher population density is needed as soybeans are planted into June and July.) For the full report on population density: https://soybeanresearchinfo.com/wp-content/uploads/2021/02/FINAL.2700-002-20-Seeding-Rate_Science-for-Success_Dec-23_v1-1.pdf
Interested in more?
Soybean agronomists Shawn Conley (University of Wisconsin- Madison), Seth Naeve, (University of Minnesota), and Rachel Vann (North Carolina State University) will be discussing these topics during a Planting Considerations webinar on Friday, Feb 19 at 12:45-1:45 PM. Click here to register: https://www.eventbrite.com/e/science-for-success-soybean-planting-considerations-tickets-140292814585?utm-medium=discovery&utm-campaign=social&utm-content=attendeeshare&aff=escb&utm-source=cp&utm-term=listing