Metcalfe, Darrel S., 1913- Crop production : principles and practices / Darrel S. Metcalfe, Donald M. Elkins. - 4th ed. - New York : Macmillan, c1980. - ix, 774 p. : ill. ISBN: 0023807105 Subjects--Topical Terms: Field crops. LC Class. No.: SB185 / .H75 1980 Dewey Class. No.: 633