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, 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
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]
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 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