by H.P. Ulrich ... [and others] ; United States Department of Agriculture, Bureau of Plant Industry in cooperation with the Purdue University Agricultural Experiment Station
by L.R. Smith ... [and others] ; United States Department of Agriculture, Bureau of Plant Industry in cooperation with the Purdue University Agricultural Experiment Station
by H.P. Ulrich ... [and others] ; United States Department of Agriculture, Agricultural Research Administration, Bureau of Plant Industry, Soils, and Agricultural Engineering in cooperation with the Purdue University Agricultural Experiment Station
United States Department of Agriculture, Natural Resources Conservation Service ; in cooperation with Purdue University Agricultural Experiment Station and Indiana Department of Natural Resources, Division of Soil Conservation and State Soil Conservation Board
by B. H. Hendrickson ... [and others] ; Management of the soils of Ohio and Switzerland Counties by A. T. Wiancko and S. D. Conner ; United States Department of Agriculture, Bureau of Chemistry and Soils
by O. C. Rogers [and others] ; United States Department of Agriculture, Agricultural Research Administration, Bureau of Plant Industry, Soils, and Agricultural Engineering
By C. S. Simmons ... [and others], United States Department of Agriculture, Bureau of Chemistry and Soils ; in cooperation with the Purdue University Agricultural Experiment Station
by H.P. Ulrich ... [and others] ; with a section on management of the soils of Bartholomew County, by A.T. Wiancko ; United States Department of Agriculture, Agricultural Research Administration, Bureau of Plant Industry, Soils, and Agricultural Engineering in cooperation with the Purdue University Agricultural Experiment Station
by O.C. Rogers ... [and others] ; [United States Department of Agriculture, Agricultural Research Administration, Bureau of Plant Industry, Soils, and Agricultural Engineering in cooperation with the Purdue University Agricultural Experiment Station]
by H.P. Ulrich ... [and others] ; [United States Department of Agriculture, Agricultural Research Administration, Bureau of Plant Industry, Soils, and Agricultural Engineering in cooperation with the Purdue University Agricultural Experiment Station]
United States Department of Agriculture, Natural Resources Conservation Service ; in cooperation with Purdue University Agricultural Experiment Station, and Indiana Department of Natural Resources, Division of Soil Conservation and State Soil Conservation Board
by O.C. Rogers ... [and others] ; [United States Department of Agriculture, Bureau of Plant Industry, Soils, and Agricultural Engineering, Agricultural Research Administration in cooperation with the Purdue University Agricultural Experiment Station]
by D.R. Kunkel ... [and others] ; United States Department of Agriculture, Bureau of Plant Industry, in cooperation with Purdue University Agricultural Experiment Station