James Morris, Will Hamman, Jason Hartschuh, CCA, Elizabeth Hawkins
The variability of the 2019 cropping year is continuing into harvest. With a broad range of planting dates this spring, many soybean producers will be faced with variable harvest conditions. Additionally, the hot and dry conditions this late summer into early fall has sped up the senescence and dry down of many soybean fields. While seed quality is currently very good, a few weeks of wet weather can degrade quality quickly. Be sure you are ready when the soybeans are.
When harvesting soybeans, harvest loss can be a real concern. The ideal time to harvest soybeans is when the soybean seed reaches 12-15% moisture. This will allow for optimal threshing and reduced harvest loss. Harvest loss can be very simply calculated by getting out of the combine and counting the soybean seeds on the ground. By randomly selecting a 1-foot by 1-foot area in a harvested part of the field, a producer can estimate harvest loss. Counting 4 soybean seeds per square foot is equal to 1 bushel/acre of loss. Due to the mechanical nature of a combine it is nearly impossible to gather every soybean seed in the field. An acceptable level of loss is 3% of yield or less, which is equivalent to 1-2 bushels/acre. If harvest conditions and combine adjustments are not optimal, harvest loss can reach 10% of yield and that can become very costly to the producer.
It is important for the combine operator to be checking harvest loss as well has the quality of the grain in the combine grain tank. Harvest loss can occur in three areas: 1) pre-harvest, 2) header and 3) combine. One should check these three areas within different locations in a field. Checking behind the combine represents total harvest loss, but one must check pre-harvest loss before combining an area, as well as just behind the header after harvested (header loss). Combine loss equals the total harvest loss minus the pre-harvest loss and header loss. Checking all three areas determines if and what combine settings must be adjusted, especially header loss.
It is recommended to review the owner’s manual and/or consult your local combine dealer for help on proper combine settings specific to the crop and harvest conditions. Fine tuning adjustments from these settings will help optimize the effectiveness of the combine. Adjustments should be based on harvest conditions and grain samples from the tank, looking for cracked or damaged soybeans seeds as well as the amount of pod material or unthreshed pods in the sample, see Table 1 below for acceptable levels.