sol-, -sol +
(Latin: base, ground, soil, bottom; the lowest part of something; sole of the foot or a shoe)
Soil orders are named by adding the suffix -sol to a root word, as shown in the table of the United States Soil Taxonomy and the soil classification system of the Food and Agriculture Organization, FAO (agency of the United Nations).
Many of the applicable soilwords which are listed and defined in this unit do not use the -sol suffix; however, they are included because they are essential parts of the major listings of the U.S. Soil Taxonomy and the Food and Agriculture Organization presentations.
The soil groups are based on extensive sets of field and laboratory observations and on extensive technical criteria.
Their natural vegetation is woodland or forests, which in some areas has given way to tree savanna maintained by seasonal burning.
The age, mineralogy, and extensive leaching of these soils have led to low levels of plant nutrients, excess aluminum, and high erodibility, all of which make agriculture problematic.
Traditional shifting cultivation of acid-tolerant crops has adapted well to the conditions found in Acrisols.
They occupy just under eight percent of the continental land surface on earth, covering areas throughout central and northern Latin America, Southeast Asia, and West Africa.
Acrisols are defined by the presence of a subsurface layer of accumulated kaolinitic clays where less than half of the ions available to plants are calcium, magnesium, sodium, or potassium and also by the lack of an extensively leached layer below the surface horizon (uppermost layer).
They are related taxonomically to the Oxisol soil order of the U.S. Soil Taxonomy.
Related FAO soil groups originating in tropical climates and also containing layers with clay accumulations are Lixisols and Nitisols.2. From the classification system of the Food and Agriculture Organization, FAO.
3. Etymology: from Latin acer, "strong acid".
They form in cold climates on relatively flat terrain which supports boreal landscapes, taiga, or coniferous or mixed forest.
High acidity, low plant-nutrient content, and fragile aggregate structures are common to these soils.
These adverse climatic and chemical conditions, combined with the impeding clay layer, prevent agricultural use; except in areas, where the growing season is sufficient to allow grazing, cold-hardy grains, or acid-tolerant root crops.
Occupying 2.5 percent of the total land area on earth, Albeluvisols are concentrated in a belt from Poland to Siberia in Eurasia and from Baffin Bay westward in Canada.
As their subsurface layer structure indicates, they tend to be associated with the FAO soil groups of Podzols to the north and Luvisols to the south.2. From the classification system of the Food and Agriculture Organization, FAO.
3. Etymology: from Latin albus, "white".
These soils have mainly formed under the forests and they have a subsurface horizon in which clays have accumulated.
Alfisols are primarily located in temperate humid and subhumid regions of the world and that combination of generally favorable climate and high native fertility allows Alfisols to be very productive soils for both agricultural and silvicultural (tree growing) development.
Alfisols are divided into five suborders: Aqualfs, Cryalfs, Udalfs, Ustalfs, and Xeralfs; which are defined alphabetically in other parts of this unit.2. From the U.S. Soil Taxonomy soil-order classification system.
3. Etymology: from alf, an abbreviation for aluminum and ferrum, "iron".
Alfisols are arable (cultivatable) soils with water content adequate for at least three consecutive months of the growing season.
Before cultivation, the soils are covered with natural broad-leaved deciduous forest vegetation, sometimes interspersed with needle-leaved evergreen forest or with grass.
Occupying just under ten percent of the nonpolar continental land area on earth, they are found primarily in cool, moist regions of the Northern Hemisphere (the north-central United States and north-central Europe extending into Russia) and in subhumid or Mediterranean climatic regions of both hemispheres (western Africa south of the Sahara, northeastern Brazil, and southern Australia).
The principal agricultural crops grown on Alfisols are corn (maize), wheat, and wine grapes.
Alfisols typically present well-developed, contrasting soil horizons (layers) depleted in calcium carbonate but enriched in aluminum-bearing and iron-bearing minerals.
Below the surface horizon, there is a region with significant accumulation of translocated (migrated) layer silicate clay.
This area which is called the argillic horizon, is characterized by a relatively high content of available calcium, magnesium, potassium, and sodium ions.
Alfisols are lower in humus content than Mollisols (a similar soil order) and do not have the calcium carbonate accumulation of that soil type
They are less extensively leached of metal ions and develop in cooler climates than the Ultisols, a clay-rich soil order of warmer regions.
Liming and fertilization are essential to their agricultural use; primarily for growing oil palm, corn (maize), and cotton.
Their extent has not been established definitively, but they are believed to occupy less than one percent of the total land area on earth, predominately in the southeastern United States (in soil zones currently classified as Acrisols) and Malaysia.
Alisols are characterized by the presence of a dense subsurface layer of accumulated clay of mixed mineralogy (mostly kaolinitic) containing a significant amount of readily soluble aluminum ions bound to soil particles and by the lack of an extensively leached layer below the surface horizon (uppermost layer).
They take place under the same topographic conditions as Acrisols but in climates with greater precipitation and higher temperatures.
Alisols are also related to the Lixisol and Nitisol groups in the FAO classification system and to the Ultisol order of the U.S. Soil Taxonomy.2. From the classification system of the Food and Agriculture Organization, FAO.
3. Etymology: from Latin alumen, "aluminum".
Andisols are divided into eight suborders: Aquands, Gelands, Cryands, Torrands, Xerands, Vitrands, Ustands, and Udands all of which are defined in this unit.2. From the U.S. Soil Taxonomy soil-order classification system.
3. Etymology: from Japanese an do, "dark soil".
They are found from Iceland to Indonesia, but they typically occur in wooded highland areas of the continental lands bordering the Pacific Ocean.
Andosols have high aluminum content, and their reactions with inorganic phosphate render the phosphate essentially insoluble and unavailable for intake by plants.
Although the soils have excellent water-holding and nutrient capacity (unless leached extensively), their strong reaction with phosphate makes agriculture without fertilizing doubtful.
Andosols are similar to the Andisol order of the U.S. Soil Taxonomy.2. From the soil classification system of the Food and Agriculture Organization, FAO.
3. Etymology: from Japanese an do, "dark soil".
These soils vary widely in their biological, chemical, and physical properties which occupy 0.004 percent of the continental land surface of the earth, and as such, they are growing in extent along with the influence of human society on the soil environment.2. From the classification system of the Food and Agriculture Organization, FAO.
3. Etymology: from Greek anthropos, "humans, mankind".