Be aware of soybean harvest losses

Farm Forum

BROOKINGS — In 2013 more than 4.5 million acres of soybeans were harvested in South Dakota making it one of the major crops grown in the state. The USDA predicts yet another record soybean crop for 2014 with a national total of 3.8 billion bushels. This is up 16 percent from last year said David Karki, SDSU Extension Agronomy Field Specialist.

At the same time, Brazil, another world soybean producer also saw their record production during this year. Because of this record production, Karki said 2014 soybean prices are expected to take a hit. “There was a slow start this season due to continuous precipitation in June in several parts of the state. We are now however at the corner of harvesting this season’s long effort,” he said.

In order maximize yield, Karki said growers need to minimize losses at harvest time.

Below he outlines a few things growers should consider to keep losses to a minimum this harvest.

Pre-harvest Losses

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 percent of the pods are turned brown or mature color. The moisture content during this stage is about 35 percent. Harvesting soybeans as soon as the seed moisture content is below 15 percent significantly reduces the pre-harvest losses.

In fairly warm and dry conditions, seed moisture will generally drop down to 13-14 percent after five to 10 days after physiological maturity. However, the first two weeks of September 2014 will see chances for precipitation, according to recent weather predictions.

Harvesting Losses

Yield losses during harvesting are mainly during gathering. There are four kinds of gathering losses.

• Shatter Loss: shelled beans and pods fall to the ground without going into the combine.

• Stubble Loss: pods that remain on the stubble.

• Stalk Loss: pods attached to the stalks that were cut but not carried into the 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 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. Then- disengage and raise the platform, and back up about 20 feet. Then lay a 10 square feet 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 is equal to about 1 bushel loss per acre.

If the total loss is more than 3 percent of the yield, (i.e. at 40 bushels per acre), growers 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.

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