United States Department of Agriculture, Soil Conservation Service ; in cooperation with Iowa Agriculture and Home Economics Experiment Station; Cooperative Extension Service, Iowa State University; and Department of Soil Conservation, State of Iowa
United States Department of Agriculture, Soil Conservation Service ; in cooperation with Iowa Agriculture and Home Economics Experiment Station and Cooperative Extension Service, Iowa State University, and the Department of Soil Conservation, State of Iowa
United States Department of Agriculture, Soil Conservation Service ; in cooperation with Iowa Agriculture and Home Economics Experiment Station, Cooperative Extension Service, Iowa State University, and Department of Soil Conservation, State of Iowa