‘Silage Soybeans’: The 2024 Green Stem Phenomenon
Green stems might slow the combines down a little, but there is no concern about it affecting grain quality.
The 2024 growing season, while smooth for much of the region once crops were finally in the ground, kept us on edge until the very end. Cool temperatures early in the season slowed progress, and it wasn’t until the heat arrived in late summer that things turned around. Suddenly, corn and soybeans raced to the finish line at breakneck speed.
This rapid progression left us with an unusual scenario: dry grain paired with green vegetation. Soybean grain moisture levels were among the lowest we’ve ever seen, with combines hitting the fields to harvest crops already at 10% moisture and falling fast. However, many growers hesitated to roll their combines because, despite the bone-dry grain, many fields were still full of vibrant, grass-green plants with leaves intact.
Depending on where you live, you may be familiar with this phenomenon. However, for many farms in our region, it was a brand-new experience—at least on the scale we observed. In much of the agricultural industry, this condition is referred to as green stem syndrome, where the seeds and pods are dry, but the rest of the plant remains green. This year, we jokingly dubbed it “silage soybeans.”
Why Does It Happen?
There’s no concrete answer for why we see green-stemmed soybeans. One theory is the abundant fall heat pushed the plants to maturity so quickly the seeds finished development before the plant could shut down its “factory.” Without the typical resource draw to fill pods, leaves didn’t senesce, and stems remained green.
Fortunately, green-stemmed soybeans have little to no impact on grain quality. In seasons like this, where the grain is dry and ready for harvest, there’s minimal concern about staining, smearing or other issues that might affect quality.
The downside? Harvesting may take longer. Green stems can slow down combines and may require adjustments to your reel to prevent stems from wrapping around it, which could lead to header loss. While it might take some extra time to “chew” through the green stems, the final product will still meet quality expectations.
The good news is green stem syndrome is relatively rare in our region, and we can chalk 2024 up to another learning opportunity.
