How did technology hurt the tenant farmers?

As farms are increasingly being mechanised, farmers feel that they are being kicked off there own land. They believe that mechanized tractors and ploughs divide man from his land. Machine man is the new breed of agribusiness that knows nothing of the soul behind working the land,

"the machine man, driving a dead tractor on the land he does not know and love, understands only chemistry; and he is contemptuous of the land and of himself. When the corrugated iron doors are shut, he goes home, and his home is not the land."

This is one of the major themes of the novel.