Study shows early planting boosted soybean yields with residual herbicides
In Colorado, the Weed Science Society of America said that a recently published research in the journal Weed Technology shows that early planted soybean fields nearly always resulted in higher yields than mid- to late-planted fields, and that any soybean stand reductions from using soil residual herbicide programs did not contribute to yield loss compared to herbicide programs without them.
The study’s researchers conducted field experiments during 2024 and 2025 at three Purdue Agricultural Centers (PAC) at latitudes representing northern, central, and southern agricultural regions in Indiana. These sites included: the Pinney PAC, near Wanatah, in the north; the Throckmorton PAC, near LaFayette, in central Indiana, and the Southeast (SE) PAC, near Butlerville.
The experiments found that “an early planting date resulted in a greater yield than for mid-late and late planting dates at all site-years, except in SEPAC 2024,” states Estevan G. Cason, Graduate Research Assistant, Department of Botany and Plant Pathology, Purdue University, and the study’s corresponding author. “In that site-year, drastically lower temperatures after planting caused a 35% stand reduction in early-planted soybean compared with late planting, resulting in a 15% yield reduction.”
Overall, early planting during the field experiments correlated with slightly thinner (13 to 23%) soybean stand counts, when compared to later planting dates, but those reduced stands only reduced yields during SEPAC 2024. In addition, “early planting resulted in slightly more soybean injury (5 to 10%) from residual herbicides than later planting dates, but [that] did not translate into yield loss,” report the researchers. “The inclusion of residual herbicides at any soybean planting date, at either full or reduced rates, did not cause yield reductions compared with programs without residual herbicides.”
Category: Food & Agriculture
