Thirty years of crop rotations on the common prairie soil of illinois
Hopkins, C.G., Readhimer, J.E., Eckhardt, WM.G.
Thirty years of crop rotations on the common prairie soil of illinois - Illinois 1908 - 323-356 p. - Crop Rotation, Soil Illinois Agricultural Experiment Station. Bulletin No.125 .
Thirty years of crop rotations on the common prairie soil of illinois - Illinois 1908 - 323-356 p. - Crop Rotation, Soil Illinois Agricultural Experiment Station. Bulletin No.125 .