the cause of this boom is debated. whether the settlement of the west was a cause or effect of the boom is one of the most important issues. globally the economy was improving with the end of the long depression. the last semi-humid farmland in the united states was exhausted, leaving canada with the best unexploited farm land in north america. technological changes from the steel plow to combine harvesters played an important role, but perhaps the most important development was the practice of dry farming that allowed farmers to profitably grow wheat on the semi-arid southern prairies.