Fuel prices, however, can be among the most volatile costs farmers encounter each year because much of it is imported. While an increase in domestic energy production has helped thwart major supply disruptions, Miller said tensions abroad could affect what farmers pay for fuel in the U.S.

"We have to be a concerned because of the unrest in the Middle East," he said. "It could quickly change the fuel-price outlook."

Farmers who have wanted to purchase new tractors, combines, implements or other machinery have encountered increasing prices. Machinery prices increased by an average of 7.4 percent per year from 2002 to 2012 because record-high farm incomes increased demand.

The sustained increases in machinery prices could quickly come to a halt, especially for used farm equipment, if commodity prices decline and stay down for an extended period of time, Miller said.

As producers make their decisions about inputs for the 2014 crop year, Miller said the bottom line is that they should keep an eye on the economics of each decision. For fertilizer, that means waiting to see if prices continue to decline, while it also means going ahead and spending the money now for seed that best fits individual production systems.

For chemicals, Miller said it means determining whether the benefits outweigh the costs.

"Farmers always need to look for ways to be more efficient by looking for ways to drive down the cost per unit of output," he said. "They also need to be cautious with capital investments, such as equipment and land purchases and rents."

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