By SHELLY STRAUTZ-SPRINGBORN
Michigan Correspondent

STANTON, Mich. — The smell of rotten potatoes spread on area farm fields earlier this year is driving a field trial under way in Montcalm County, to study the feasibility of composting cull potatoes in the future.

Jeremy Sova, district conservationist with the Montcalm Conservation District, is conducting the trial with Larry Sackett, who produces approximately 150 million pounds of potatoes per year on about 10,000 acres in Montcalm, Gratiot and Isabella counties, and Brad Morgan, owner of Morgan Composting in Sears, Mich., who is providing the equipment and expertise to conduct the three-month trial.

“Twenty percent of last year’s crop was lost to late blight,” Sova said. “A lot of stored potatoes rotted over the course of the winter.”
To get rid of the spoiled potatoes, farmers spread them on their fields in the spring. This year, that meant a higher concentration of the foul-smelling crop, which drew attention from some residents near the fields.

“Potato growers are required to apply them at agronomic rates based on soil tests. There’s nothing illegal about what the farmers were doing,” Sova said. “But, one of the biggest problems is odor. We’re looking for other options to spreading them.”

With Morgan’s expertise, a composting pile approximately 200-by-12-feet was created at Sackett’s farm near Edmore using a 12-inch base of wood chips, topped with 5.5 feet of potatoes and capped with two inches of fly ash to help keep down the odor.

Early in the trial, which began in May, Sova said, “The odor had been reduced considerably. From a visual perspective, the pile is more appealing than potatoes spread all over the field.”

In addition to quelling the foul odor of spoiled potatoes, one of the primary goals of the trial is to determine if composting can be successful in killing potato tubers that harbor the late blight pathogen.

“The object is to kill any potentially hazardous pathogens so we don’t spread them to other potato fields,” Morgan said.
That means the pile has to reach a consistent temperature of about 122 degrees. Morgan added a challenge is to look at the economics of composting to determine if it’s a cost-effective option for farmers.

“We have to consider if we can reduce volume economically, and if there’s a value for the finished product on the other end,” he said. “In the end, we hope there’s enough benefit to the farm to offset the expense.”

The trial, he said, “has validated what we can do. Now, we just need to figure out how to make it more economical on a larger scale, using the resources that we have.”

The compost will be tested for nutrient value at the end of the trial. “We want the finished product to be a high-quality compost that can be spread back on the fields to return the nutrients in a stable form, and also provide organic matter to the soil,” Sova said.
“Realistically, we can change the nutrient value – we can add poultry manure if we need to and have a valuable product,” Morgan added.