Erosión y desertificación.-Combating erosion as the main effective factor in land degradation in arid and semi-arid regions of Iran

Abstract

ABSTRACT Soil erosion is one of the most important environmental problems in the world including Iran. For decreasing the impacts of soil erosion, soil conservation measures are required. For successful soil conservation measures, obtaining information about the relative importance of sediment source and their shares in sediment production is required. There are different methods for determining the relative importance of sediment sources, among which tracing or source studies are emphasized in recent years due to their privileges. In this research, sediment sources were identified in Amrovan Drainage Basin, Semnan Province, Iran, using tracing method. A small earth dam is constructed at the outlet of Amrovan Drainage Basin in 1993. Sediments are accumulated in the reservoir of dam. In this study, sediments were sampled from dam reservoir, different sources were also sampled. Fifteen tracers were first selected for tracing which are: the amounts of N, Carbon, Cr, Co, Mg, K, Na, smectite, cholorite, illite, kaolinite, PH and two magnetic properties consisting of XLF and XFD. The samples were analyzed in the laboratory for these parameters and different statistical methods were applied to the data including Nonparametric Kruskal Walis Test, Stepwise Differentiation Function Analysis. The results have shown that the main sediment source is Upper Red formation consisting of evaporitic marls. Keywords: Erosion, Sedimentation, Small dams, Semnan Province, Iran, Tracing, Fingerprinting, Source studies.