Capability of Soil Taxonomy (2014) compared to updated WRB (2015) in describing Lut Desert soils

Soil classification is a useful tool for understanding and managing soils. The objective of the present research was to compare the capability of Soil Taxonomy (ST, 2014) and World Reference Base for soil resources (WRB, 2015) systems related to soil description and classification in Lut Desert. Marginal and central parts of Lut with typical aridic/thermic and extreme aridic/hyperthermic soil moisture/temperature regimes were selected. Twelve representative pedons on alluvial fan, plain, rock pediment, Gandom Beryan lava plateau, and playa were described and sampled. The obtained results showed further capability of the WRB system to reflect soil forming processes. However, it could be recommended to add anhydritic qualifier to Solonchaks, Solonetz, and Gypsisols, aquatic qualifier to Solonchaks and Solonetz, and abruptic, leptic, and paralithic qualifiers to Solonchaks. The ST system has not been successful in expressing soil forming processes due to considering only two great groups for saline soils and giving priority to Salids in comparison with the other suborders of Aridisols. That is why Petrosalids, Gypsisalids, Natrisalids, and Argisalids great groups and Anhydritic Natrisalids, Anhydritic Argisalids, Anhydritic gypsisalids, Anhydritic Petrosalids, Calcic Natrisalids, Calcic Argisalids, Calcic Gypsisalids, Natric Petrosalids, Natric Haplosalids, Natric Gypsisalids, Petrogypsic Petrosalids, and Epipetrosalic Aquisalids subgroups are suggested to be added to Soil Taxonomy system. Meanwhile, defining anhydritic horizon and considering textural differences in strongly contrasting particle size class of family level and aquic conditions in playa are among the merits of Soil Taxonomy. Nonetheless, it could be suggested to remove (or adopt) color (Hue) requirement of anhydritic horizon.