Canada ranks sixth in the world in wheat production and is the second largest exporter of wheat with 70% of its production exported annually. Since 1960, wheat yields have doubled in Canada. A group of Canadian researchers set out to identify the key factors accounting for the yield increase…

From abstract: “Therefore, we suggest that chemical weed control was the main contributing factor to the yield increases. This control has resulted not only in reduced competition from weeds, but also in better seedbed moisture because fewer cultivations are needed in the spring. “

“Because of the ability to control weeds with chemicals, it is now also possible to seed shallowly into a moist seedbed immediately after one cultivation since numerous spring cultivations with a resultant loss of valuable soil moisture are no longer necessary to eliminate germinating seeds. Fertilizer application and improved cultivars have also contributed, but to a lesser degree, to the yield increases.”

Authors: S. Freyman et al.
Affiliation: Agriculture Canada, Lethbridge, Alberta, Canada
Title: Yield trends on long-term dryland wheat rotations at Lethbridge.
Publication: Canadian Journal of Plant Science. (1981) 61:609-619.