Morphology, Physico-Chemical Properties and Classification of Soils on Terraces of the Tigris River in the South-east Anatolia Region of Turkey

Alluvial soils, formed by rivers as accumulated sediment deposited at different times, show large variations in their properties over short distances. The main aims of this study were to determine the morphological and physicochemical properties and classify the soil profiles of four different geomorphological units along transects on the right bank of the Tigris River in the Hevsel Bahceleri district of Diyarbakır. These soils were formed on the quaternary alluvial deposits on the young and old terraces, and the flood plain. The formation of soils was highly associated with major climatic factors and parent materials influenced the soils morphological and physico-chemical characteristics. Soil profiles formed on the old terraces located far from the Tigris River had well developed vertical succession horizons. The profile formed on the floodplain was characterized by weak pedogenesis. Development of the B horizon (Bw, Bt, Bss) and carbonate accumulation were the main pedogenic processes in terrace soils, whereas the profile formed on the floodplain had redoximorphic features at less than 2 m depth. According to analytical and morphological data, the four soil profiles were classified as Entisol, Inceptisol, Alfisol and Vertisol.