Abstract:In desert alkalized soils, the alkalinity can be induced by both the hydrolysis of exchangeable sodium (or magnesium) in soil and that of the salts such as Na2CO3, NaHCO3, MgCO3, Na2SiO3, etc., at the same time, the determination of exchangeable properties is moredifficult due to the presence of line and gypsum in soils; therefore, hgdrolytic alkalinity is suggested by the authors as the new index for the division of alkalization of the sods. For providing our suggestion, hydrolytic alkalinity, pH, ESP, exchangeable sodium, residual sodium carbonate and SAR of 31 profiles were determined and the data obtained were studied using comprhensive numerical analysis method.