Comparing Soil Taxonomy (2014) and updated WRB (2015) for describing calcareous and gypsiferous soils, Central Iran

• We compared WRB (2015) with Soil Taxonomy (2014) to classify soils of central Iran
• WRB system classified soils of the area more efficiently than Soil Taxonomy
• We suggest addition of anhydritic horizon to Solonchaks of WRB system
• Paralithic qualifier is also recommended to be added to Calcisols of WRB system
• Salic and anhydritic great groups and subgroups are suggested to be added to Ustepts of Soil Taxonomy

Soil classification is a useful tool for understanding and managing soils. Latest editions of Soil Taxonomy (2014) and WRB (2015) were compared for classification of calcareous and gypsiferous soils of southern Kerman in the present research. Soils along Jiroft-Kahnooj transect with ustic and hyperthermic moisture and temperature regimes were selected. Eleven pedons were described and sampled. Routine physical and chemical analyses were performed and soils were classified according to Soil Taxonomy (2014) and WRB (2015) systems. Calcic, gypsic, anhydritic, salic, argillic (argic), and cambic diagnostic horizons were investigated after field and laboratory work. Based on the findings of the research, it is recommended that new Calciustalfs and Saliustepts great groups and Salic Anhydritic Calciustepts, Salic Calciustepts, Anhydritic Calciustepts, and Anhydritic Saliustepts subgroups are added to Soil Taxonomy (2014) classification system. Anhydritic diagnostic horizon, property, or material and paralithic qualifier were also suggested for WRB (2015) classification system. Calcium carbonate equivalent percentage needed for calcic horizon in WRB (2015) system is suggested to be re-defined as the 2.c required characteristics of calcic horizon in Soil Taxonomy (2014) system. Results of the study showed that WRB (2015) classification system using various qualifiers and specifiers could classify soils of the area, especially saline soils, more efficiently than Soil Taxonomy.