Their age and mineralogy have led to low levels of plant nutrients and a high erodibility, making agriculture possible only with frequent fertilizer applications, minimum tillage, and careful erosion control.
Perennial crops are more suitable for these soils than root or tuber crops and they occupy just under 3.5 percent of the continental land area on earth, primarily in east-central Brazil, India, and West Africa.
Lixisols are defined by the presence of a subsurface layer of accumulated kaolinitic clays, where at least half of the readily displaceable ions are calcium, magnesium, sodium, or potassium; but they are also identified by the absence of an extensively leached layer below the surface horizon (uppermost layer).
They are related to the Oxisol order of the U.S. Soil Taxonomy and the related FAO soil groups originating in tropical climates and also containing layers with clay accumulations are Acrisols and Nitisols.2. From the classification system of the Food and Agriculture Organization, FAO.
3. Etymology: from Latin lixivia, "washing".