Soybean response to high-speed planting in Mississippi

Mississippi soybean [Glycine max (L.) Mer.] producers are under pressure to plant as much land as possible within narrow planting windows. The 5-year average planting progress is 45% of the total at the end of the optimal soybean planting window. New metering and seed delivery technology claims faster planting without sacrificing singulation, stand, or yield, but these tools need to be validated before recommendation. This study aimed to quantify soybean response to planting speeds using a precision planter (John Deere MaxEmerge 2 row units retrofitted with Ag Leader SureSpeed and SureForce) and a mechanical planter (John Deere 1700 ground-driven mechanical planter equipped with eSet meters) for a total of 7 site-years across Mississippi. In 2022, both planters were evaluated at four actual ground speeds of 7.9, 10.8, 13.5, and 16.4 km h⁻¹ in a 2 × 4 factorial design. The experimental design was modified in 2023, where the mechanical planter served as the current farmer practice check at 9.7 km h⁻¹and the precision planter speeds were 9.7, 14.5, and 17.7 km h⁻¹ at research station sites and 9.7 and 14.5 km h⁻¹ at an on-farm site. Across sites, increased planting speed generally increased plant spacing, in-row spacing variability, and decreased plant population. However, increased speed did not affect soybean yield. The precision planter at 17.7 km h⁻¹ was no different from the mechanical planter in terms of soybean plant population, spacing, and yield in 2023. Results suggest soybean producers can plant soybean at 17.7 km h⁻¹ without compromising yield.