ABSTRACT
The preceding chapters have shown that the array of adjustments which man is making to arid zone conditions today is highly diverse and is changing rapidly. While the basic complexes of rock, soil, water and vegetation are altering slightly in some places, such as in managed grazing lands, or are deteriorating tragically, as in the irrigated flood plain of the Lower Indus, their productive use is fluctuating more widely. Increasingly, decisions are made by public agencies to expand cultivation in one sector – as in the dry lands of the USSR– or to curb it in another place – as in overgrazed mountain slopes of Baluchistan and the United States. These are large-scale efforts. But the growth of technology available to farmers, the opening up of monetary economies in isolated or semi-subsistence communities, and the enforcement of internal security have also made it possible for individual farmers, grazers, miners and recreation seekers to press into new areas and to shift their means of livelihood quickly. Many parts of both the interior and the margins of the arid zone are in a state of flux. The traditionally restless state of the nomad is more than matched by the surging margins and shifting present-day occupation of the interior of the zone.
