Combine Attachment Offers On-the-Fly Peanut Cleaning

Some peanut farmers find it worthwhile, time and cost permitting, to rid their harvests of loose-shelled kernels, undersized pods and other debris. Now, a new screening attachment for peanut combines could simplify this marketing decision.

That’s the implication of results from Agricultural Research Service studies conducted during a five-year cooperative agreement with Amadas Industries, Inc., that concluded earlier this year. The Suffolk, Va., company and ARS scientists collaborated in outfitting Amadas’ combines with a screen attachment to remove debris “on-the-fly.”

In west Texas and North Carolina, some farmers now clean their harvests using low- capacity screens that must be “parked” in the cropfield and require a two- to three- person operating crew. Other farmers transport their peanuts to cleaning facilities at commercial buying points, for a fee.

In the mid-1990s, two Grace, N.C., farmers--Leon Umphlett and his son Robbie-- decided to save some of the time and cost of cleaning peanuts by rigging their Amadas combines with screening attachments. After limited field evaluations, Amadas and Paul Blankenship’s group at ARS’ National Peanut Research Lab in Dawson, Ga. sought to streamline the Umphlett design.

The result was a 10-foot-long cylindrical trommel comprising meshlike material called hardware cloth that rests atop the combine. Driven by hydraulic motors, it rotates on a slight incline to filter-out debris that clings to peanut pods. Once cleaned, the pods empty into the combine’s basket.

On average, loose kernels, undersized pods and other debris account for nearly 5 percent of a peanut lot’s total weight. But in 38 test runs with either runner or Virginia-type peanuts on farms in five states, the combine-mounted trommel reduced the lots' total debris weight to 2 to 3 percent. Studies from Blankenship's lab also suggest removing undersized or damaged pods may cut the risk of a peanut lot’s contamination by aflatoxin, a fungal carcinogen.

Amadas now markets the trommels as a combine accessory, and has sold 20 to 25 of them.

ARS is the U.S. Department of Agriculture’s chief scientific research agency.