Soybean harvest can be delayed for many reasons, from uncooperative weather to equipment downtime. Other times, a lack of adequate harvest planning and scheduling may be the hold up. There are many physical ways yield loss occurs when harvest is delayed, but field loss and moisture levels are generally the reason.
Two ways soybean yield loss happens:
1. Field loss
Field loss ranging from 5–12% of total yield potential can occur before and during harvest.1 Over half of that field loss is typically attributed to header, or threshing losses, related to combine efficiency. Delaying harvest until soybeans are below 11% moisture can increase the likelihood of pod shattering. Repeated drying and wetting cycles can further increase yield losses while waiting to harvest. Harvesting early and properly adjusting your combine are two of the best ways to minimize these types of losses. Harvesting at moisture content of 13–13.5% is optimal for minimizing mechanical damage. If bins are equipped to air dry soybeans, harvest can start as early as 16–18% moisture and easily aerate to 13% to help minimize field loss.
2. Soybean moisture loss and influence on yield calculations
A standard bushel of soybeans weighs 60 lbs. at a standard 13% moisture. Soybeans delivered at moisture levels greater than 13% are usually discounted by the buyer using a calculated discount rate. Weight loss from soybeans with moisture levels less than 13% is not taken into consideration for calculating total bushels sold. The moisture loss results in reduced harvest weights and fewer bushels sold.
The chart below illustrates the percent of total yield loss for every moisture point below 13%. As a result, soybeans discounted for being wetter than 13% can sometimes be more profitable than delivering drier beans. The following example calculates soybeans delivered at 14% moisture with a 3% price discount, compared to the same soybeans delivered at 8% moisture. The calculation below doesn’t account for the incremental field loss that likely occurred from a delayed harvest.
Example:
3% price dock of original price ($8.50/bu) = $8.25 x 80 bu/A = $660 gross per acre
5.4% yield reduction x 80 bu/A = 4.3 bu less – 80 bu/A = 75.7 bu x $8.50/bu = $643 gross per acre
Insights to remember:
- Soybean harvest losses can be managed by timely harvest and proper combine adjustments, which may be needed multiple times throughout the day, depending on changing moisture and weather
- Check each field closely as soybeans with green stems or a few remaining leaves may be drier than perceived
- Avoid harvesting when beans are at their driest for the day, such as on hot afternoons, to reduce pod shatter; 4–5 seeds per square foot found on the ground is the equivalent of 1 bushel per acre yield loss
- Soybeans that dried down and became wet again during rain and cool, cloudy weather will more easily split and shatter, so be extra careful harvesting in such situations
- Timing is everything when it comes to soybean harvest because optimum moisture is key to combining the best yields
Visit with your local Golden Harvest Seed Advisor with questions or for more agronomic insights.
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