The sale, expected to close in the second quarter, is part of a review Agrium completed last year that led to Agrium restructuring its three divisions into two business units.
Koch Fertilizer is a subsidiary of Kansas-based Koch Industries Inc
Agrium shares were down more than 1 percent in Toronto and New York in late morning trading.
(Reporting by Rod Nickel in Winnipeg, Manitoba; Editing by Marguerita Choy)