Fertility in illinois soil
Hopkins, Cyril G., Pettit, James H.
Fertility in illinois soil - Illinois 1908 - 187-294 p. - Fertility, Soils Illinois Agricultural Experiment Station. Bulletin No.123 .
Fertility in illinois soil - Illinois 1908 - 187-294 p. - Fertility, Soils Illinois Agricultural Experiment Station. Bulletin No.123 .