The USDA is predicting a record soybean crop for 2014 with a total of 3.8 billion bushels, up 16% from last year. Also another big world soybean producer Brazil saw their record production during this year.
Because of this record production it is expected for soybean prices to take a hit this fall. We are now at the corner of harvesting this season’s long effort. In order maximize yield, we need to reduce to a minimum losses at harvest time.
The following are things we should consider while harvesting soybeans.
Pre-harvest loss can occur due to shattering or detached pods, therefore timeliness of the harvest is very essential. The plants are considered physiologically mature when 95% of the pods are turned brown or matured color. The moisture content during this stage is about 35% (Hoeft et al, 2000).
Harvesting soybeans as soon as the seed moisture content is below 15% significantly reduces the pre-harvest losses. In fairly warm and dry conditions, seed moisture will generally drop down to 13% to 14% after 5 to 10 days after physiological maturity.
Yield losses during harvesting are mainly accounted for gathering loss. There are four kinds of gathering loss.
- Shatter Loss: Shelled beans and pods fall on to the ground without going in to the combine
- Stubble Loss: Pods that remain on the stubble
- Stalk Loss: Pods attached to the stalks that were cut but not carried into threshing unit
- Lodge Loss: Pods attached to the stalks that were neither cut nor delivered into the combine
Another type of loss occurring during harvest is the loss due to machine handling where beans will pass through the combine but remain in the pod or the threshed beans which go out of the combine with the trash. Proper setting and adjustments of machine parts as recommended in the manual can reduce these losses during harvest.
Determining Harvesting Losses
When beginning to harvest, drive the combine away from the edge of the field and stop. Disengage and raise the platform, and back up about 20 feet. Then lay a 10-square-foot frame across the harvested swath at the rear end of the combine.
Count the loose beans, beans in the pod on or off stalks, and beans in pods on the stubble that are inside the frame and divide this number by 40 to estimate bushels per acre loss. Four soybeans per square foot equals about one bushel loss per acre. If the total loss is more than 3% of the yield (i.e. at 40 bushel per acre rate), you should determine where the loss is coming from.
If most is pre-harvest loss, there is not much you can expect to do. Pre-harvest loss can be determined by placing the same frame across the rows not harvested.