Evaluating the land use potential of gypsiferous soils from field pedogenic characteristics

Although gypsiferous soils cover approximately 100 million ha in the world, it is only in the past two decades that their pedogenic and agronomic properties have been better understood and their classification improved. There is still no method to assess adequately their production potential. This paper focuses on gypsum accumulation forms as diagnostic criteria for a rapid soil suitability appraisal in the field. Pseudomycelia, gypsum spots, powdery coatings and other localized In situ precipitations usually indicate soils with less than 15% gypsum. Depending on their intensity and depth of occurrence in the root zone, they define a soil environment which is suitable for semi-sensitive and semi-tolerant crops. Continuous gypsum accumulations characterize soils or horizons with high (e.g. more than 25%) gypsum contents, and these can be used only for tolerant crops. The land use potential of gypsiferous soils is primarily determined by: (a) the depth of the impermeable layer, (b) the gypsum content within the root zone, and (c) the crop tolerance level. ii method is proposed to assess the land suitability of gypsiferous soils on the basis of these criteria.