INFERRING THE ORIGIN OF A SALT CRUST OVER SALINE SOILS BY ITS CHEMICAL PARAMETERS

Soil samples from an area affected with high soil salinity in central Chihuahua, Mexico, were analyzed for the customary chemical analyses: pH, electrical conductivity, and alkalinity. Subsequently, they were analyzed in more detail for their content of carbonate, bicarbonate, chloride, and sulfate ions, and for the cations Mg, Na, B, and Ca. Size distribution and organic matter content were also determined. Aided by these analyses, the origin of the salts affecting the soil were discriminated between the following options: (1) salts existed in the soil naturally, (2) salts were formed by evaporation of surface water used for irrigation, and (3) salts were formed by evaporation of groundwater used for irrigation. Possible differences resulting from varying soil:water ratios utilized in conducting the tests are discussed, as well as the usefulness of customary vs. more detailed chemical determinations for this type of soil affliction. Implications from these results affecting remote sensing studies on soil salinity are addressed.