Des Moines Register: A group representing 200,000 U.S. farmers filed a complaint with the federal government today, saying Deere & Co. is using its market power to restrict growers’ ability to repair their own tractors and combines. The National Farmers Union, representing Iowa and five other affiliated state groups, filed a complaint with the Federal Trade Commission, asking for an investigation into what the groups say are “the company’s abusive restrictions on tractor and other farm equipment repair.”