green soybean stems

Green Stems At Harvest

September 19, 2023

Prior to a killing frost, green soybean stems with dry grain moistures have become a concern in a number of varieties from a number of companies. I realize that green stems through the combine make an unsettling sound and can be cause for concern. This year, again, with above-average plant height and an increased lodging potential, green stemmed plants accumulating on the platform adds to this unrest… Is it a problem?

It depends on your perspective. In past years where this has occurred, it equated to some very respectable yields. Is there a genetic link? Yes! Varieties bred with stronger tolerances to late-season diseases, such as brown stem rot, generally have a greener, healthier plant longer into the growing season, which also increases their yield potential. Viral infections such as bean pod mottle virus can also cause spotty green stemmed areas within a field.

Most producers would agree that although green-stemmed soybeans pose an issue during harvest prior to a frost, the yield results from these varieties in question are generally some of the best results they encounter.

On the flip side of this conversation, some producers historically try to wait for the frost to lessen the green stem chances at harvest. Usually in doing this, they can encounter excessive soybean shattering out of the pods at the reel/sickle of their platforms as they harvest. Is this a genetic link? There are varieties more prone to shattering. The culprit usually is that in waiting for the stems to dry and lose moisture, grain continues to dry below 8% in some of these cases. When grain gets that dry, genetic tolerances to this problem are not what is at issue.


Dr. John McNamara // Wilbur-Ellis Agronomist