Iowa. State Planning Board. Committee on Land UtilizationNegative. "Iowa state plan." "Project 1030." "1030-17."1 map : black line ; 84 x 115 cmJPEG2000706118305; MAPG4151_J61_1932_I6.jp2islandora: testiadep_1814https://digital.lib.uiowa.edu/node/791514engUniversity of Northern IowaPublicYield of corn: average yield of corn in bushels per acre, by region 1928-1932: state average 37.57MapsIowa1930-1940University of Iowa