Energy prices, a big part of farmers’ yearly costs, are turning out to be a bright spot in a very difficult year for agriculture. Ample supplies are pushing down prices for propane, natural gas and diesel fuel, which is reducing farmers’ costs, according to officials at the Iowa Department of Agriculture and Land Stewardship (IDALS) and Iowa State University (ISU).

According to Harold Hommes, IDALS marketing bureau chief, propane values held pretty steady throughout the year, including the fall and...