As the dispossessed stream out of the Plains land, the houses of the tenant farmers are left vacant. The only life left in the area is the shiny metal sheds that house the tractors. However, unlike the horse that continues to live after a day's work, the tractor is dead once its motor is turned off. This machine has made the job of the farmer too easy, so one can no longer wonder at the miracle of growth that rises from the land. Eventually, the houses die as well. Windows are broken, shingles loosened and tossed by the wind, until the only ones who disturb the dust on the floor are the wild animals from the fields.
In this chapter, Steinbeck continues to draw a sharp contrast between the vitality of those who live close to the land and the mechanical lifelessness of those who use the soil for capital concerns. This theme is indicative of Jeffersonian agrarianism, which focus on the life-giving bond between human beings and the land with which they work. This theme is characterized by the sense of decay and death that hangs over the land abandoned by the farmers. Like the "muzzled" and "goggled" driver in Chapter 5, the man who runs the tractor goes home at night, distanced from the life growing in the fields he sows. Without the human element invested in the continuation of the life cycle, there can be no life. When the tractor is turned off, it dies. Similarly, when the farming families leave the region, they take life with them, which is symbolized by the wasting away of the vacant houses. Left to die, the houses are gradually taken over by nature, soon to revert to dust.
corrugated iron sheet iron or steel with parallel grooves and ridges to give it added strength in construction.