A Pivotal Date And Good Math Can Lead To Higher Soybean Yields

By: John Hart

For farmers to maximize their soybean yields, they need to do the math.

Speaking at the recent Piedmont Soybean Field Day at the Piedmont Research Station in Salisbury, N.C., Dr. Ron Heiniger, North Carolina State University Extension cropping systems specialist, said four components make up the mathematics of soybean yield: Nodes per acre, pods per node, beans per pod and seed weight.

“The math is complicated because these factors interact with each other. The more nodes I put out per acre the more difficulty I have putting on pods per node,” Heiniger said.

Nodes per acre is critical and to understand nodes per acre farmers need to remember June 21, the longest day of the year. After June 21, the nights begin to lengthen, and flowering is triggered on soybean plants.

“For a determinant variety, flowering stops node production. That’s why it’s important to know that date because it will be when a determinant variety stops all node production by the soybean plant. For an indeterminant variety, Groups II and IV, we can still get more nodes per acre, but the plants slow down node production. June 21 is a seminal day. It also has an impact on pods per node,” Heiniger said.

To maximize light to the soybean plant and to maximize nodes and pods, Heiniger encourages farmers to plant early. It is critical to get as much time between the planting date and flowering to get more nodes on the soybean plant.