Dr. Floyd F. Hedlund, 71, an authority in international trade who was a former Agriculture Department official and a retired lieutenant colonel in the Air Force Reserves, died of cardiac arrest Feb. 5 at Georgetown University Hospital. He lived in Washington.

Dr. Hedlund worked for Agriculture for 36 years before retiring in 1979. He spent his last 16 years as director of the fruit and vegetable division of the Agriculture Marketing Service.

He also had been a delegate to the U.N. Food and Agriculture Committee and had worked with the Agency for International Development, the Central Treaty Organization and the Office of Economic Cooperation and Development.

He was a 1974 recipient of the Agriculture Department's highest award, the Distinguished Service Award.

Dr. Hedlund was a native of Chappell, Neb. He moved to the Washington area in 1937. He served in the Army Air Forces during World War II. He was a graduate of the University of Nebraska and earned a doctorate in agricultural economics at Cornell University.

He had been a deacon of of St. Paul's Lutheran Church in Washington. He was a member of the National Press Club, the American and International Farm Economic associations and the Congressional Country Club.

Survivors include his wife, Delia M., of Washington; two sisters, Hazel Guenin of Oshkosh, Neb., and Ople Kruse of Springfield, Mo., and two brothers, Clarence L. of Mesa, Ariz., and Earl C. of Annandale.