By Scott Krone
We all know there are many factors that affect soybean yield throughout the growing season. Given that many cannot be controlled, greater emphasis must be placed on the areas we can influence. Four key factors to keep in mind are stand density, planting date, maturity group and genetic yield potential. What makes these decisions so powerful is that the payoff comes from planning, not spending.
Before the planter ever reaches the field, management decisions already account for roughly 15% of soybean yield. While that may seem like a small portion, data from thousands of GDM Multi‑Environment Trials across the U.S. show that an incorrect variety and planting date combination can reduce yield by 10 to 12 bushels per acre.
As a grower, it is easy to get a narrow focus on seeding rate and stand count. While they are critical, there is rarely any significant yield loss when planted at the recommended stand density. We, as GDM agronomists, have shown this in our multi-year population study with stands as low as 50,000 plants/A. Anything below that rate for a final stand should be replanted. Historical weed pressure and herbicides used should be taken into consideration.
Unlike many crops, soybeans respond to open space by adjusting their growth habits rather than losing yield. Prioritize planting date and genetic selection, not stand counts alone. Shows that, when compared with genotype and planting date, not a single region falls below the penalty threshold into the area of loss from stand density.
Farmers know that planting too late is when the greatest yield loss will be seen, but knowing when that time frame occurs is important. According to GDM’s extensive trial network that started in 2019, we have found that there is a critical planting date. Anything planted after that critical date will suffer yield loss.
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