Aridisols (or desert soils) are a soil order in USA soil taxonomy. Aridisols (from the Latin aridus, for “dry”) form in an arid or semi-arid climate. Aridisols dominate the deserts and xeric shrublands which occupy about one third of the Earth's land surface. Aridisols have a very low concentration of organic matter. Water deficiency is the major defining characteristic of Aridisols. Also required is sufficient age to exhibit sub-soil weathering and development. Imperfect leaching… (More on Aridisols)