An Analysis on Properties and Potential of Salt Affected Soils in Khorat Basin was conducted on selected representative soils at 15 locations in Nakhon Ratchasima, Roi-Et, Chaiyaphum, Khon Kaen, Maha Sarakham and Buriram Provinces. Methodology used included both field study method and laboratory analysis. Results of the study reveal that most of salt affected soils in the study are Alfisols, having moderate to high profile development. These soils are somewhat poorly to poorly drained, having moderate to low permeability, and occupying low terrace region. The salt effect on these soils have been due to the improper water and land management. Exchangeable sodium percentage of these soils is generally more than 15, and their electrical conductivity values are more than 4 deciseimen per meter. All of these soils can be classified as saline-sodic soils. Their base saturation percentages are generally high (40-80%) and they have high soluble salts, especially sodium and chloride ions. Based on their difference in reaction ranges, they can be differentiated into 3 groups comprising acid soils, alkaline soils and soils with slightly acid surface and mildly alkaline subsurface layers. These soils have generally low to very low content of organic matter, total nitrogen, available phosphorus and available potassium but their cation exchange capacity is high to very high. They posses poor physical properties. Their bulk density values are high (1.56-2.49 Mg m(-3) and their values of available water for plants are moderate to low. Minerals in clay fraction of these soils are mainly kaolinite , smeatite and illite , and quartz dominates their silt fraction. These soils have moderate to very low fertility. Due to excess salts these soils have low to very low productivity. These salt affected soils can be differentiated into 6 types as follows: Non Thai type having moderate salinity, slightly acid to mildly alkaline reaction

Ban Kham type having moderately high salinity and alkaline reaction

Phutthaisong type having moderately hight salinity and acid reaction

Ban Wang type having high salinilt and alkaline reaction

Phimai type having high salinity and acid reaction, and Non Kha type having high salinity and slightly acid to mildly alkaline reaction. The development stages of these soils are saline-sodic and saline-sodic-acid. These salt affected soils have more agricultural potential for paddy rice cultivation than that for cultivation of upland crops ,tree crops or pasture. In any case these soils need be ameliorated with suitable combined managements of soil, water and plant . It includes leaching to reduce the effect of salinity and sodicity , increasing organic matter and proper fertilizer application, using good quality water having good irrigation planning and using some suitable varieties of halophytes.