Agrium said Monday that Schmidt was making the move as a result of his appointment as chief executive of Louis Dreyfus Commodities, a seller and trader of agricultural commodities.
Schmidt's appointment was announced by the Dutch company on Nov. 28 and becomes effective Jan. 5.
Under his leadership between 2000 until his departure from Viterra in 2012, the Wheat Pool business evolved from a regional co-operative into a publicly traded international agribusiness.
Viterra was later purchased and taken private by Swiss commodities giant Glencore, while parts of the business were sold to Agrium and Richardson International.
Schmidt joined the board of Agrium — a Calgary-based fertilizer producer and agriproducts retailer — in 2013.