Don Halcomb, a 63-year-old farmer in Adairville, Ky., is expecting his profit to vanish this year, largely because of the confluence of falling crop prices and rising costs for seeds and other materials.

The price of an 80,000-kernel bag of seed corn rose to $300 from $80 in the last decade, as the companies that produced them consolidated, he said. And with the recent decline in commodity prices, Mr. Halcomb said he expects to lose $100 an acre this year.

“We’re producing our crops at a loss now, just like the oil guys are pumping oil at a loss,” Mr. Halcomb, who grows corn, soybeans, wheat and barley on his 7,000-acre family farm, said by telephone on Wednesday. “You can’t cut your costs fast enough.”

It is a common plight of farmers across the United States, with the global agriculture industry in a wrenching downturn. Because farmers have produced too much corn, wheat and soybeans, they have been forced to slash prices to sell their crops. They have also reduced spending on seeds, pesticides and fertilizer, which has eaten into sales at agribusiness giants, including Monsanto and DuPont.