(A) the pastoral movement allowed time for natural restoration of soil.
(B) the pattern of cyclic movement allowed the pasture to recover and also prevented overuse of the natural resources.
(C) they give time to the overgrazed land to recover.
(D) the exhausted or unusable land becomes fertile by the time the pastoral nomads come back
(E) environmentalists and economists have increasingly come to recognize that pastoral nomadism enchances the fertility of the land.