Differentiating the natural and man-made terraces of Lake Van, Eastern Anatolia, utilizing earth science methods

The Fertile Crescent of the Middle East region, embracing Syria, eastern Turkey and Iraq, marks the region where settled agriculture began, and where the landscape has been shaped for millennia by human activities. The lacustrine and fluvial terraces of the Late Pleistocene and Holocene Eras are common geomorphic features in many areas around Lake Van in eastern Turkey, being sustainably used since the Urartian Period (800-400 years bc). Fluctuations in the water levels of Lake Van have resulted in the development of widely distributed natural terraces around the Lake. The undulating slopes of these terraces have limited their cultivation, however, leading people to reconstruct terraces as a means for utilizing particular production sites, as anthroscapes (this concept is generally confined to situations where marked differences or deviations from the normal, natural landscapes are attributable to effects/shaping by humans). The region exhibits semiarid climatic conditions and a short crop-growing season, currently being under the threat of land degradation. Recent mismanagement of these lands as a result of increasing population pressures has led to the degradation of both the natural and the man-made terraces. Thus, there is an urgent need to conserve and understand the indigenous management and soil quality attributes of these man-made terraces. To this end, this study examined soil profiles and analysed soil samples for their chemical, physical and mineralogical characteristics, in order to determine the human effects of leaching and/or accumulation. These analyses revealed significant differences between the physical, chemical, microbiological and mineralogical properties of the man-made/reworked terraces and natural terraces under essentially similar parent materials and environment, thereby providing clues as to the sustainable management of these land surfaces in eastern Turkey. The approaches used in this study provide useful evidence for attempting to explain the historical evolution of land use in similar environments elsewhere, as well as the significance of terraces in combating coastal erosion in lake environments. © Journal compilation © 2008 Blackwell Publishing Asia Pty Ltd