by United States. Soil Conservation Service

1939

by United States. Soil Conservation Service

1957

by United States. Superintendent of Documents

1985

by National Education Association of the United States. Department of Rural Education

1930

by United States. Department of Agriculture

1927

by United States. Bureau of Agricultural Economics

1930

by United States. Soil Conservation Service

1930

by United States. Soil Conservation Service

1925

by United States

1927

by United States. Congress. House

1929

by United States National Museum

1928

by United States. Department of Agriculture. Library

1927