The study of genesis and micromorphological properties of saline – sodic soils of the west of Urmia Lake

Micromorphology is the branch of soil science that is concerned with the description, interpretation and, to an increasing extent, the measurement of components, features and fabrics in soils at microscopic level. The advantage of micromorphology is that, in micromorphological studies the soils are studied in their natural and undisturbed form and so, one can follow the processes that take place in a low rate. In this research, in order to study the micromorphic properties of saline-sodic soils in the west of Urmia Lake, four soil profiles were studied. The profiles were described and classified using standard methods. Disturbed soil samples were used for physic-chemical analysis and thin sections were prepared from undisturbed and oriented samples and were studied using polarizing microscope. According to the results, the most of studied soils were apedal and their voids were mainly vughs and channels. These soils were vughy, channel and massive microstructure and their b-fabric were mainly crystallitic. The micromorphic pedofeatures in these soils were illuvial clay coatings, accumulations salts as discontinues coatings of cubic and suhedral halite crystals on voids and aggregates, continues halite coatings and halite infillings in vughs and channels, calcium carbonate accumulations as typic nodules, infillings and coatings, redoximorphic accumulations as nodules in the groundmass and coatings on voids and skeletal grains, and finally, organic coatings as black films on peds and in some cases mixed with groundmass of the soil.