The significance of the land in Cather's narrative is that acts as a symbol and as an adversary. Claude's farmland is a symbol for his inner character and for his psychological agitation. His psychological urge is toward "an intense kind of hope, an intense kind of pain,—the conviction that there was something splendid about life, if he could but find it."
Claude lay still, his arms under his head, looking up at the hard, polished blue sky, watching the flocks of crows go over from the fields where they fed on shattered grain, ... He knew that his father was sometimes called a "land hog" by the country people, and he himself had begun to feel that it was not right ... [and that] the people who didn't have it were slaves to them.
Claude's psychological urge is very important to the later development of the effects, function and psychological impact of the war on Claude's psyche.
The land that becomes battlefields is adversarial land. This foreign land--foreign for being in other countries and foreign for functioning in unaccountable ways--becomes the adversary while Claude and his fellow soldiers are hit by shells and sent hurtling in an avalanche of dirt into the ravine at their feet. There, the land grows broken bodies and bodies that will decay where it might be growing the grains and corns of home.
Then he swelled again, and burst. This was repeated, he didn't know how often. He soon realized that he was lying under a great weight of earth; his body, not his head. He felt rain falling on his face.