Frost-Damaged Soybeans - Harvesting and Handling Tips

Monday, October 30, 2023

Frost damage can pose a significant challenge for soybean farmers, but there are steps that can be taken to salvage affected crops and minimize losses. The timing of the frost event, the growth stage of the soybeans, and the subsequent handling of the crop are all critical factors.

Assess Growth Stage: The R6 growth stage is considered the minimum threshold for salvaging soybeans for grain harvest. R6 is reached when beans fully fill one pod on one of the upper four nodes of the main stem in 50% of the plants. If frost occurs before this stage, yield reductions are likely to be significant.

Combine Adjustment: Frost-damaged soybeans are typically wetter and more difficult to thresh. To improve threshing performance, reduce the concave clearance and/or increase the speed of the cylinder/rotor. Make incremental adjustments and monitor progress after each change.

Harvest Moisture Levels: Soybeans that have experienced severe frost/freeze damage may dry down slowly. To avoid significant harvest delays, consider harvesting frost-damaged fields at moisture levels between 16% and 18%. However, keep in mind that the beans will need to be dried to a safe moisture level for storage (12% for six months).

Moisture Meter Adjustment: Electronic moisture meters may underestimate moisture levels in green and immature soybeans. When testing mixtures of green, immature, and mature beans, add 1 to 1.5 percentage points to the moisture meter readings and adjust drying times accordingly.

Drying with Ambient Air: If only a small percentage of moisture needs to be removed (2-3 percentage points) and air temperature is above 60°F with relative humidity below 75%, no additional heat is required in drying bins equipped with full perforated floors and fans. However, drying will be slow and depends on initial moisture content, air flow, grain depth, and weather conditions.

Drying with a High-Temperature Dryer: Exercise caution when using high-temperature dryers for soybeans, as they are more fragile than corn. Normally, soybeans are dried at temperatures below 130°F to prevent seed coat cracking and split beans. For food-grade and seed beans, maintain relative humidity above 40% to protect seed coat integrity.

Storage of Frost-Damaged Beans: Elevators may discount or even reject loads containing green and immature soybeans. To improve marketability, screen out small beans, dry the rest to 12% moisture, and store them in aerated bins for a few months.

By following these tips, farmers can increase their chances of salvaging frost-damaged soybean crops and minimizing losses.