The study of effects of Urmia Lake on Physico-chemical properties and clay mineralogy of soils in Dizadj Dol region of Urmia

In order to study the effects of Urmia Lake on physicochemical and mineralogical properties of soils in Dizadj Dol region, 24 soil profiles in two soil sequences with the similar parent material, topography and climate were investigated. One of these sequences is affected by Urmia Lake and the other one is not affected. According to the results, all of the profiles which have been affected by the Lake have nitric horizons. Natric horizons in these soils have been formed due to high amounts of sodium ions resulted from UrmiaLake. Varivace analysis of physico-chemical properties of these soils showed that the values of soil organic carbon, CEC, EC, exchangeable Na, ESP and pH of the two sequences were significantly different (P≤ 0.01), but soil depth, clay content and calcium carbonate equivalent were not significantly different. Analysis of clay mineralogy showed that the clay mineral composition in these sequences were mostly smectite, illite, kaolinite, chlorite and vermiculite. Smectites and vermiculites in these soils are mainly of pedogenic origin and have been formed via transformation of illite. In the soils which have been affected by Urmia Lake, the main origin of smectites was neoformation process from soil solution. Illites, chlorites and kaolinite are inherited from parent material. Comparision of results of soils in these two sequences showed that the upraise of Urmia Lake has lead low amount of organic carbon and to high amounts of EC, exchangable sodium, ESP, CEC, pH and higher amounts of smectite in the soils affected by Urmia Lake.