First, the nomads and sedentary population complement each other in their seasonal use of land and pastures. As the Kurds, Lurs, and Bakhtiyari move out of their winter pastures in the uplands of Mesopotamia, the Arabs move in with flocks of camels and goats that can subsist on these pastures which by this time are too dry for the flocks of the long-range pastoral nomads. The sedentary villagers also graze their flocks on these vacated pastures and on the stubble of the recently harvested grain fields. This successive use of pasture by different groups follows the tribes all the way up to the summer pastures. This pattern is repeated again in the autumn when they return.
In other words, the pattern of succession in any one locality is adapted to the seasonal changes in the carrying capacity of that locality, so as to maintain a balance between the rate of utilization and the rate of production, between land and capacity.
Thus the use of the land by long-range nomads, transhumant nomads, and sedentary agriculturalists, each with a smaller number of animals and of different strains and at different times, permits the maximal use of the land.
As was mentioned, the tribes of Kurdistan and Pars were largely stock raising while the tribes of Luristan were more self-sufficient and produced many of their own agricultural products. The former tribes obtain needed agricultural products through trade and exchange with the sedentary villages and urban bazaars. In some instances the villagers act as middlemen between the nomads and these urban-centered bazaars. Pastoral nomads also obtain these products and some of the wealth of the sedentary population through their role as robbers and brigands; this varies
according to local and central political control and the political state of the tribe itself. Rents, taxes, and dues, both in cash and in kind, collected by the nomads and their tribal leaders acting in their role as landlords or government tax collectors, is another way an exchange can occur.
This presupposes the necessary force and authority to collect the tax. Nomads also rent lands or hire themselves out as laborers either to raise these products or to obtain them in exchange for their labor. Most caravan trade is in the hands of urban entrepreneurs, but a limited amount is carried during the tribal migration.
Implicit in the problem of economic exchange and land usage is the question of suzerainty because of the conflicts which arise between the nomad and the sedentary agriculturalist.
The sedentary villagers are subject to damage and even destruction of their crops, pastures, and water systems; raids and brigandage; and overlordship and extortion of ruinous dues. The villagers have recourse to politicalmilitary organization, usually in the form of local representatives of the central government, fortifications, and flight. If the settled society is dominant over the nomad it, too, can exact ruinous levies, halt the migration and seriously damage the basis of nomadic economy, extend the cultivated area and hinder the movement of the nomads, and ; disarm and remove the military threat always posed by them.
Another form of nomad-sedentary conflict is that of invasion and occupation by foreign nomads. The various Mongol-Turkic invasions of the ninth through fifteenth century are examples of this, and, as was mentioned, the arrival of the Qashqa’i was part of this process.