Abstract
Soil salinity is very huge problem of the world. Sultanate of Oman being a part of arid regions is also very badly hit by this problem. The survey data indicated that 1.56 m ha were affected from salinity within suitable agricultural land that was calculated to be 70.25% of the total cultural land. Salt affected area within unsuitable agriculture is 12.32 m ha that is 39.21 % of the total geographical area of the country. Thus, total salt affected area (13.88 m ha) was 44.18 of the total geographical area of the country. The losses from crops due to salinity have been estimated as 49.04 m$ while that from abandoning of date palm orchards are 4.47 m$ which would make the total as 53.51 m$. The main causes of salinity are the climatic conditions (Scanty rainfall and high temperature), nearness to sea, salty parent material and development of secondary salinity due to consistent usage of very saline water. Many soils have a surface accumulation of secondary lime, which may also be Aeolian. The salinization of irrigated soils by groundwater has become a major process of soil formation in many areas of the Sultanate, particularly, in coastal areas. Salt pans in many soils can be attributed to Aeolian addition originating from the nearby sea through wind flows towards the inland. The genesis and classification studies indicted that salt affected soils in Oman belong to only two orders, the Aridisols and Entisols. The suborder are; Salids, Psamments, Fluvents and Orthents while great group is Typic. The subgroups are mostly Typic Aquisalids, Typic Haplogypsids, Typic Calcigypsids, Typic Haplocalcids and Typic Torrifluvents. Key words: Causes, origin, genesis, extent, soil salinity, Oman
