LUVISOL

one of the 30 soil groups in the classification system of the Food and Agriculture Organization (FAO). The mixed mineralogy, high nutrient content, and good drainage of these soils make them suitable for a wide range of agriculture, from grains to orchards to vineyards. Luvisols form on flat or gently sloping landscapes under climatic regimes that range from cool temperate to warm Mediterranean. Occupying just over 5 percent of the total continental land area on Earth, they are found typically in west-central Russia, the United States, central Europe, the Mediterranean basin, and southern Australia. Luvisols are technically characterized by a surface accumulation of humus overlying an extensively leached layer that is nearly devoid of clay and iron-bearing minerals. Below the latter lies a layer of mixed clay accumulation that has high levels of available nutrient ions comprising calcium, magnesium, sodium, or potassium. Luvisols are often associated with Cambisols. Albeluvisols are a related FAO soil group also exhibiting clay migration.