Recently, I was looking at a soybean field planted to an MG 5 determinate variety in Rapides Parish,and the producer asked about flowers and pods that had fallen from the plant.
Due to the structure of a soybean flower, almost all the flowers produced will be fertilized. Mainly, this is due to the proximity of the pollen to the ovaries within a single flower. In normal years, even in good environmental conditions, soybean plants will lose over half of the fertilized flowers or pods.
On each node, multiple flowers will be positioned on pedicels that are connected to a single rachis. Normally, the first three pods on a rachis have the best chance of survival.
If the plant is under stressful conditions, abscission of the lower flowers or pods can occur. Examples of stressful conditions leading to an increase in flower or pod abscission are drought, high temperatures, defoliation and shade.
If abscission occurs to older flowers or pods, soybean plants can compensate by the increased chance of survival of the flowers or pods towards the top of the rachis if the environmental conditions improve.
Unfortunately, if the pod survives, any seed within the pod can be terminated at any time.
To maximize yield, maintain as many best management practices as possible throughout the growing and harvest season.