American Family Farmer

KEVIN SKUNES is a vice president at the National Corn Growers Association and a fourth-generation farmer outside Arthur, North Dakota. On his 6,000 acres, he currently raises about 55 percent corn, 45 percent soybeans. This constitutes a big change since Skunes was a child in the 1960s. Back then, the farm was about 2,000 acres of wheat, barley, sunflowers and soybeans, with no corn.Farmers who had long rotated plantings among a diverse group of grains are increasingly turning to a single one. Corn has always been a mainstay of U.S. agriculture, but its increasing profitability has driven up corn's share of total production, while grains such as wheat, oats and sorghum have steadily fallen, according to a Bloomberg analysis of a half-century of crop data. This locks farmers, as well as machinery-makers including Deere & Co., to the rises and falls of one crop, as both domestic and export markets grow more and more tied to the dominant U.S. grain. That exposes farmers to greater volatility and greater trad