Soil productivity indexes for Illinois counties and soil associations / [prepared by P. W. Mausel, E. C. A. Runge, and S. G. Carmer].
Carmer, S. G.
Mausel, P. W.
Runge, Edward C. A.
University of Illinois at Urbana-Champaign, College of Agriculture, Agricultural Experiment Station,
Bulletin (University of Illinois at Urbana-Champaign. Agricultural Experiment Station)