Prime Planting Dates Identified for U.S. Soybeans
Published: Friday, April 11, 2025
Soybean production in the U.S. has evolved significantly over the past two decades, with a growing emphasis on early planting to maximize yields.
The Early Soybean Production System (ESPS), developed by Arkansas, Mississippi and Louisiana researchers, uses mid- to late-maturity group 4 soybean varieties, planted between mid-to-late-April, to maximize yield potential. Because of the early planting dates, soybean flowering and grain fill occur during cooler parts of the summer, improving water use efficiency and minimizing heat stress. Additionally, flowering and pod set occur during the longest days of the year, typically resulting in higher pod counts, contributing to increased yields. Timely planting is also key to minimizing lodging.
A two-year field study conducted by Mississippi State University evaluated the effects of planting dates on soybean growth and yield using MG 4 and MG 5 soybean varieties at two locations. Planting dates spanned from late March through mid-July. Results indicated that final plant height increased with later planting dates through early June. However, soybean yield was highest with an April 20 planting date and decreased with later planting dates.
Soybeans planted around April 20 achieved an average yield of more than 70 bushels per acre while those planted a month later yielded around 60 bushels per acre.
Additionally, Pioneer agronomists conducted a field study in the Mississippi Delta to evaluate the effect of planting date on the yield and lodging of two indeterminate Pioneer brand soybean varieties (MG 4.7 and 4.9). The study included planting dates on April 9, April 23, May 10 and May 24.
Results showed that the highest soybean yields for both varieties occurred with the April 23 planting date. Additionally, lodging was significantly reduced for both varieties with April planting dates compared to May planting dates.
If considering planting soybeans before mid-April, Steve Cromley, Pioneer field agronomist, suggests taking several precautions to minimize the risk of freeze damage.
"Start by planting tilled fields with little to no residue and avoid beginning in creek or river bottom fields," Cromley said. "Low-lying areas are more prone to freeze damage."
Cromley also recommends planting at normal depths, rather than shallow, to protect seedlings.
Additional tips for early planting include: using a quality seed treatment to protect against early season diseases, selecting a variety with strong resistance to sudden death syndrome (SDS) and increasing seeding rates by 10 to 20% to compensate for potential seedling mortality under early planting conditions.
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