This wouldn’t be the first time a father and a son didn’t see eye to eye on a crop management decision. In this case, the son wants to start planting soybeans on the same day they start planting corn. The goal is April 20. Dad wants to concentrate on corn first and start planting soybeans around the second week of May. Fortunately, they’re both willing to listen to what agronomists have to say rather than fight it out.
The panel of Indiana Certified Crop Advisers offering information so they can make a decision includes Jesse Grogan, LG Seeds, Lafayette; Greg Kneubuhler, owner of G&K Concepts, Harlan; and Tom Stein, manager of the Boswell and Templeton branches for Ceres Solutions.
Grogan: Optimum corn and soybean planting dates are similar when long-term averages are considered. However, soybeans emerge from the soil as cotyledons. Stressful soil conditions that limit soybean emergence compared to corn are more common early in the season. Also, an early frost can damage emerged soybeans more than corn. Highest yields for soybeans are from planting in the last week of April to early May, and decline rapidly by the end of May into June.
Kneubuhler: I favor early soybean planting. Once you get the bugs out of the corn planter and get it rolling, start the bean planter right behind it. Our data has shown earlier-planted soybeans will tend to yield more than later-planted beans on average. Soybeans are daylight-sensitive and move through growth stages accordingly. Likewise, if you plant a soybean early, you give it an opportunity to add more foliage during vegetative growth stages, which in turn tends to offer more chance for a higher pod set by more nodes per plant. You will also tend to create quicker row closure.
Grogan: Soybeans need time to grow in the vegetative stage before flowering begins. The number of nodes produced on the main stem and canopy development for light interception are important for best yield. Early-planted beans usually produce the highest number of nodes and close the row canopy sooner. Soybeans can add about two nodes per week after the V1 growth stage. Later-planted soybeans don’t catch up to early-planted fields. Early planting of varieties with better stem and root health is most helpful.
Stein: University researchers have found that the ideal planting window for soybeans is basically the same as for corn. Early planting of soybeans into a good seedbed when soil conditions are fit allows for better establishment of a good root system before hot, dry summer weather begins. Early planting also helps establish a full crop canopy that mitigates competitions from weeds, increases utilization of solar radiation and improves available soil moisture during the growing season. An added environmental benefit to early planting is that it improves sustainability by reducing soil erosion and sedimentation by having a larger crop canopy and more prolific root system.