Six Tips for Early Planting Soybeans

Early soybean planting has been identified as a profit-enhancing management practice. See Soy Envoy Chad Kalaher’s blog this month for details on the economics of early planted soybeans. Here are six management practices to help make this practice successful for Illinois soybean growers.

Maintaining consistent planting depth is key to early planting success.

1. Soil conditions must be optimal. This seems pretty simple, but I see growers press this issue every spring. Planting into soil that is too wet or too dry can haunt you all season long. Make sure to plant into moisture, but don’t mud beans in, especially early.
2. Check the weather. When considering whether to plant soybeans early, look at the temperature forecast. For the first 48 hours after planting, soybeans go through a rapid water imbibition period. If they are exposed to temperatures below 50° F during this time, chilling injury can occur. After 48 hours, they are less susceptible to chilling, though emergence may be slow. Longer-term forecasts need to be considered as well. When soybeans are planted earlier than is customary, there is more risk of frost two to three weeks post planting. Consider this risk when planting early.
3. Use a seed treatment. With slowed emergence comes extended exposure to seedling diseases. Protecting the seed from Pythium and Rhizoctonia is extremely important. Expect bean leaf beetle pressure on early planted beans and those first to emerge. Include an insecticide in your treatment mix. Treatment products that help mitigate sudden death syndrome (SDS) should also be used when early planting.
4. Choose the right variety. Some studies indicate that using a variety that is up to one full maturity group longer than what you normally plant can increase the yield advantage with early planting. Look for varieties with high tolerance to SDS, even if you use a seed treatment for disease protection.
5. Use an appropriate planting population. Since early planted soybeans will have a longer time to grow prior to bloom, they may have a tendency to grow taller. For this reason, it may be prudent to lower plant populations in an attempt to allow the plants to branch more. This can prevent lodging as the plants mature as well as put more nodes (and more pods) on the plant. Dan Froelich, agronomist with Brandt, recommends the following seeding rates based on the company’s field research:
   1. April 15 to 30: Plant at 120,000 to 130,000
   2. May 1 to May 15: Plant at 140,000
   3. After May 15: Plant at 150,000

   Froelich explains why reducing population is a better strategy: “By reducing the population, we give plants more space and a larger amount of time to build a bigger factory, thus we need fewer plants.”

6. Plant at the appropriate depth. A crucial management decision at any planting date, it bears repeating here. Too deep early planting can make the emergence process even slower, adding to risk of seedling diseases and mortality. Planting too shallow increases the risk of the soil drying out after the seed has imbibed enough water to germinate, but before the seedling has become established, reducing population. A consistent 1.5- to 2-inch planting depth will produce the most consistent results.

Early planting allows soybeans to build a bigger factory.

While this list is far from all the management practices needed to successfully plant soybeans early in Illinois, it gives a good start. The most important thing to remember is that all practices are intertwined in a systems approach to early planting. If you plant 120,000 seeds 3 inches deep into a soil that is too wet and the temperature stays at 45° F for two weeks, your final stand may not support 100-bushel yields, even when ideal conditions exist for the rest of the growing season.

CCA Kevin Nelson is a 4R NMS at Northern Partners Cooperative. Kevin works with the Agronomy Sales Team and growers in North Central Illinois.