COLUMBUS (AP) — Many Ohio farmers will see their property taxes take a big jump next year because of imperfections in a formula used to determine farm taxes.

For some, those tax bills will double or go up even more.

“Sticker shock is a very good way to describe this,” said state Sen. Bob Peterson, a Republican from southwest Ohio who farms about 2,000 acres in Fayette County.

The Ohio Department of Taxation has a program called Current Agricultural Use Value that is designed to make farming financially easier for operators.

It calculates with farmland values based on crop yield, soil conditions and market prices. But low interest rates and swings in grain prices are revealing imperfections in the formula and adding up to higher property taxes next year.

Most of Ohio’s 75,000 farmers take part in the voluntary program because it saves them thousands of dollars annually, The Columbus Dispatch reported.

The formula used by the program is based on a rolling, seven-year average of crop prices, soil values and other measures of farm productivity. The higher bills are based on past performance.

Bill Cox, a farmer in Delaware County in central Ohio, said the formula should be adjusted to better reflect current conditions rather than what happened years ago.

His property tax will rise from $2,446 to $5,412 next year.

“The money we get for our crops this year pays for our taxes next year,” he told The Dispatch. “If they’ve got a formula, they’ve probably got some third-grader working on it.”

The Ohio Farm Bureau, which represents about two-thirds of Ohio farmers, is looking into the situation, said Amy Milam, director of legal education.

“We certainly empathize with those members who are alarmed and concerned,” she said. “They’re seeing this higher valuation now, when the farm economy isn’t as good as it was. Some are just wondering if there’s a need to review some of the methods for the formula.”