How to Successfully Harvest and Handle Frost-Damaged Soybeans

Frost-damaged soybeans are salvageable but require special knowledge and equipment to ensure viability.
Frost-damaged soybeans are salvageable but require special knowledge and equipment to ensure viability.

Late-October frost has led many soybean growers to a familiar inflection point at harvest season: How to deal with frost-damaged soybeans.

Because many soybean crops were planted later in the season to account for a late wheat harvest, frost conditions occurred earlier in the soybean lifecycle. As a result, immature soybeans exposed to frost have been damaged — and growers must decide which frost-damaged soybeans can be salvaged.

Experienced growers know that a single frost is not a death sentence for soybeans — once the crop reaches a certain level of maturity, it’s possible to save certain bean pods that have been damaged. Specifically, if the soybeans have reached the R6 growth stage of maturity — where total pod weight peaks and seed growth is at its maximum but full maturity has not yet been reached — there’s hope for saving the crop.

Frost damage usually affects the upper leaves of soybean plants. If minor, it may only penetrate the canopy, where temperatures typically stay above 30 degrees Fahrenheit. However, with each subsequent freeze, the risk for damage increases. It isn’t until plants reach R7 — when one pod on the main stem has gained its mature green color in over half of the plants — that the risk is considered minor.

Adjustments to Salvage Frost-Damaged Soybeans

From an equipment standpoint, adjusting for frost-damaged soybeans means reducing concave clearance and incrementally increasing the speed of rotors and cylinders. Also, remember that electronic meters used to measure moisture tend to underestimate the levels in green, immature soybeans. It’s a good rule to add 1 to 1.5 percent to the reading when measuring moist soybeans.

As for timing, harvest should happen when moisture levels are between 16% and 18% to reduce the risk of significant loss due to shattering. Once the harvest is complete, drying frost-damaged soybeans with ambient air is suitable for small moisture reductions of 2 to 3 points — to reach 12% moisture needed for storage. During drying, maintain the relative humidity of the drying air above 40% to protect seed coats and prevent splits.

When harvest time becomes unpredictable, you need agricultural equipment and tools that are dependable. Your local John Deere dealer has the resources to handle even the most extreme frost conditions.