Evaluation of desertification intensity based on soil and water criteria in Jarghooyeh region

Abstract

Desertification refers to land degradation phenomenon in arid, semi-arid and dry sub-humid areas, resulting from various factors including climate variation and human activities. For evaluation and mapping of desertification many research have been conducted leading to regional and local models. In this research, among different existing methods IMDPA‌ was selected and desertification intensity was evaluated on the basis of 2 criteria and 8 indices including: soil (soil depth, Electrical Conductivity, texture and gravel percentage) and water (groundwater table decrease, EC, Cl concentration, Sodium Absorption Ratio). Each criterion was assessed based on the selected indices which result in qualitative mapping of each criterion cased on geometric average of the indices. Finally, sensitive map of region was extracted using geometric average of all criteria. Thematic databases, with a 1:50000 scale resolution, were integrated and elaborated in a GIS based on arc/info8, arc view3.2 and especially ILWIS. Analysis of desertification criteria in Jarghooyeh region showed that among study criteria, soil criterion is a major problem in the study area with a geometric average of 2.25 which shows medium class while water criterion with a weighted average of 1.14 stands in low class of desertification. Also, the results showed that that Electrical Conductivity index with quantitative value of 3.54 classified in very high class of degradation, and ground water recession with quantitative value of 0.05 classified in low class of desertification were the most and the least effective factor on land degradation among studied indices respectively.