Some people were sedentary before agriculture. That is, he left room for a whole array of motives, actions, practices, and evolutionary processes. Many hunter-gatherers used fire to control or manage both plants and animals in their area. Much agriculture by primitive peoples today is of the slash and burn type. Prairies and savannahs are difficult to farm.
Much agriculture is in the margin of forested lands.
The advent of the steel plow made possible settlement of the prairies and plains in the U.S. and Canada in the middle 1800's.