The arid zone of West Pakistan: geographical aspects of aridity in West Pakistan.

Abstract

In West Pakistan aridity has for long been considered from many separate aspects, climate, hydraulic engineering, irrigation engineering, crop selection etc, and there is a considerable volume of unrelated findings. This thesis represents an attempt to relate and correlate the various approaches "by establishing some of the aspects of the geographical relationship "between man and various aspects of the land. The basic environmental elements of physique, geology, structure and climate are first established, a selective approach being based on relevance to the central point of climatic aridity - Chapters 1-3. In Chapters 4, 5 and 6, are considered those elements which are physical in character, directly influenced by climate, but whose present characteristics are to a varying degree the result of the human response to dominant aridity. Thus, in considering Hydrography one must look at elements such as river-regimes and under ground water partly as fundamental parts of the landscape and also as units having a two-way reaction with man's works in irrigation, cultivation etc. Similarly Soils, and Plant Ecology are regarded as parts of a whole complex in which climatic aridity is dominant and as complexes of natural and man caused factors. The concluding Chapters 7, and 8 are devoted to a consideration of the direct human response to environment, in the past and present. Archaeological, historic and present settlement patterns not only illustrate this response, hut clarify our picture of the environment itself. Aridity finally is more than a deficiency of rainfall. The most simple human response is to live on the qualities of drought-resistance. possessed by some livestock, but extensive past oral ism in arid areas itself brings into focus some more complicated implications of climatic aridity, i.e. overgrazing, deforestation and their ecological consequences. Man as cultivator can move away from direct contact with climatic aridity, but since pre-historic times, this has merely extended the range of the effects of total aridity on himself, and extended the range of meaning, in the landscape, of the factor of aridity i.e., canals and increasing salinity, floods and barrages, wells and commercial crops.