Iowa. State Planning Board. Committee on Soils SurveyIowa state plan. "Project 1034." "1034-2."1 map : black line ; 83 x 113 cmJPEG2000706113406; MAPG4151_J4_193_I62.jp2islandora: testiadep_1807https://digital.lib.uiowa.edu/node/317027engUniversity of Northern IowaPublicErosion by soil areas: relative occurence of erosion in various soil areas of IowaMapsIowa1930-1940University of Iowa