There have been many studies done on planting soybeans in April in the Midwest and Illinois. I think it is safe to say that many farmers have seen a soybean yield bump when planting early, except for when Mother Nature intervenes. The goal of planting soybeans early in April is to reach flower or the R1 growth stage before the Summer Solstice on June 21st. Before planting in April, each farmer needs to identify the risks of planting soybeans early and then plan accordingly. It seems easier said than done, but not only do decisions need to be made on seeding depth, seed treatment, and populations, but also communication is needed on seed arrival, field, and planter preparation, and crop insurance.
My general advice has always been that if you think that the “ground is fit” for corn, then you also can plant soybeans before or at the same time as corn. Be sure to check the extended forecast for heavy rain, especially if you struggle with field drainage. I would be more concerned with cold temperatures in the forecast the further north you go and if you are planting into a lighter soil or no-till situation. The first stage of germination is the imbibitional phase, which is the fast uptake of water that usually occurs within the first 24 hours if the soil temperature is kept at 45 degrees F. When it comes to soybean imbibition, seed quality and soil temperature matter. We don’t want the soybean’s first drink to be below 40 degrees F as this could mean a significant decrease to your final stand. If the soil remains below 50 degrees F, the soybean could remain in the soil for several weeks, but your risk of slow germination, seedling disease, and overall reduced stand establishment increases.
Your goal should be to have a final soybean population stand of 75,000 – 100,000, depending on soybean genetics. Soybeans grown in the Midwest are indeterminate, and when the soybean reached the unifoliate stage, it begins to sense night length. Planting in April allows the soybeans to have a longer period of vegetative growth and to absorb sunlight, which could be setting them up for more vegetative nodes, which could mean more pods, with more seeds per plant. Early planting also results in an earlier flower or reproductive period as well as an earlier harvest with a goal of maximizing yield.
Most research has steered us towards planting a full maturity soybean variety for your region when planting early. The time spent from flower to full seed will be longer, but speed of soybean growth stages not only depends on planting date and day length, but also on variety maturity, moisture, plant health, and temperature. Many have been experimenting with planting a shorter maturity soybean earlier for marketing incentives or the earlier planting of cover crop or wheat. Be sure that the shorter season soybean variety has been tested or rated for diseases in your environment. Also, make sure that you are aware that a shorter soybean variety that is planted earlier could go through the reproductive stages very rapidly or during times of stress. Lastly, the planting of an early maturity in April could lead to the elimination of the extra nodes, pods, seeds, or overall yield that we so desperately strive for when planting soybeans early.
As Outreach Agronomist for the Illinois Soybean Association (ISA), Stephanie supports research efforts and helps communicate both in-field and edge-of-field research and validation studies to Illinois 43,000 soybean farmers. She also helps lead the demonstration and adoption of conservation agriculture practices and raises awareness of best management and continuous improvement practices for conservation agriculture in Illinois.
Stephanie has 23 years of experience that consists of agronomy, conservation, horticulture, plant diagnostics, and education. She has her bachelor’s in crop science and master’s in plant pathology from the University of Illinois. Stephanie is a Certified Crop Advisor and was named the 2018 Illinois Certified Crop Adviser Master Soybean Advisor. She also has experience with corn and soybean pathology research, crop scouting, soil testing, as well as crop consulting. Previously, she utilized her diagnostic training and collaborated with University of Illinois departmental Extension Specialists to diagnose plant health problems and prepare written responses describing the diagnosis and management recommendations as the University of Illinois Plant Clinic.
The Illinois Soybean Association (ISA) checkoff and membership programs represent more than 43,000 soybean farmers in Illinois. The checkoff funds market development, soybean production and government relations efforts, while the membership program, Illinois Soybean Growers (ISG) and the Illinois Soybean Growers PAC actively advocates for positive and impactful legislation for farmers at local, state and national levels. ISA upholds the interests of Illinois soybean farmers through promotion, advocacy, research and education with the vision of becoming a trusted partner of Illinois soybean farmers to ensure their profitability now and for future generations.