In World War I, the earth is extremely significant for soldiers; for, they live in the trenches, they fight from the trenches, they crawl on the earth when they must move out of the trenches. The earth is both protection and danger as they seek refuge in it down within the trenches as the shells explode on the surface of it.
In a passage from Chapter Four, Remarque gives Paul poetic voice as he invokes the earth in a prayer:
Earth!--Earth!--Earth!Earth with thy folds, and hollow, and holes, into which a man may fling himself and crouch down. In the spasm of terror under the hailing of annihilation, in the bellowing death of the explosions, O Earth, thou grantest us the great resisting surge of the new-won life. Our being, almost utterly carried away by the fury of the storm streams back through our hands from thee....
Further, he reflects that the soldier instinctively,atavistically,moves one part of his being at the first sound of the droning of the shells. It is not consciously that he throws himself upon the ground before a "storm of fragments" sweep harmlessly over him becaise when the "storm" is over, he cannot remember having thrown himself upon the earth. To Paul, this reaction is a "second sight." Perhaps, then, it is a reaction much like that of the child who instinctively clings to mother because Paul concludes his reflections by observing that they reach the zone where the battle front begins "and become on the instant human animals" touching Mother Earth.