Battle for the Belt: Season 2, Episode 15 – Corn and Soybean Planting Date Responses

Episode 15 of Battle for the Belt is now available: https://www.youtube.com/watch?v=rIdMuUicMGA

In Episode 15, we have another visitor from Michigan State University, Dr. Mani Singh, the Corn and Soybean Extension Specialist. He goes over his past and current research on corn and soybean planting decisions.

Dr. Singh has been studying corn and soybean planting date in Michigan for the past six years. The main take away from his research is that the soybean can deal with and adapt to non-ideal conditions (cool and wet soils) better than corn.

Soybean stands in adverse conditions do not usually look ideal; however, the soybean can make up for stand losses and have acceptable yields. In Michigan, they have seen an increased yield potential with earlier planting in soybean and have not yet planted early enough to have a yield penalty, except for when the soybeans are planted into cool and wet soils. In Michigan, there is a yield penalty for early planting of corn that corresponds well with their crop insurance plant dates.

Soybean has a smaller chance of yield penalty in early planting situations than with corn. Yield in corn is more dependent on emergence uniformity, growth and development consistency through the field, and uniform stand. Stand loss in corn is a problem because corn cannot make up for loss of plants, as it does not branch, tiller, or put on more ears if there is variable plant spacing. Whereas, the soybean plant has more plasticity in growth and can adapt to low stands and non-uniform emergence (Figure 1). Early planting should be a field-to-field decision that considers field history, soil type, and current weather conditions.

In the case of deciding to plant early, there is always a question of adjusting relative maturity to the planting date. In mid-Michigan, most soybeans planted are around a 2.5 relative maturity; however, with early planting, increasing the relative maturity to 3.0 to 3.5 or more can has had a positive result (Figure 2). The longer relative maturity can have a longer reproductive phase and grain fill, more nodes and pods. Increasing corn relative maturity between 5 and 10 days to maturity longer than normal in early planting has also increased yield. So, selecting a longer relative maturity crop in both crops when planting early is advantageous for increased yield.

What’s happening in the field?
At the Western location, the March 25^th planted soybeans that have been flowering since May 28^th are continuing to put on nodes, flowers, and pods. The pods near the bottom of the plant are starting to produce seeds (Figure 3). However, the crop is still at the R3 or beginning pod stage because staging is based on the top four nodes on the plant. The first and second planting dates of corn are at R1 (Figure 4). The silking stage of corn can last for 13 days, so there is some expected overlap in these planting dates.

At the Northwest location, there were some flowers in the first planting date (May 16^th) but not enough to be considered fully in R1. Many areas in planting date four and five were flooded out because of the consistent rain at this location.

Finally at the Wooster location, the first planting date of soybean is at R3 (April 22) and the second is starting to flower. The corn has not made it to reproductive stages yet, but the first planting date should be tasseling soon.