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An albeluvisol in the FAO World Reference Base for Soil Resources〔(FAO World Reference Base for Soil Resources, First update 2007 )〕 is a soil with a thin, dark surface horizon on a bleached subsurface horizon (an albic horizon) that tongues into a clay illuviation (Bt) horizon. The Bt horizon has an irregular or broken upper boundary resulting from the tonguing of bleached soil material into the illuviation horizon. Albeluvisols correlate with Glossaqualfs, Glossocryalfs and Glossudalfs in the USDA soil taxonomy. These soils are formed mostly in unconsolidated glacial till, lacustrine or fluvial materials or aeolian deposits such as loess. They occur on flat to undulating plains under coniferous forest or mixed forest in boreal and temperate climates with cold winters and short cool summers. The agricultural suitability of Albeluvisols is limited because of their acidity, low nutrient levels, tillage and drainage problems. In northern regions there is also a short growing season and severe frost during the long winter. The Albeluvisols of the northern taiga zone are almost exclusively under forest with small areas used for pasture or hay fields. In the southern taiga zone, less than 10 percent of the non-forested area is used for livestock farming. In the southern and western parts of the taiga in Russia arable crops, such as cereals, potatoes, sugar beet and forage maize, are found, especially on soils with higher base saturations in the subsoil. Albeluvisols cover an estimated 320 million ha in Europe, North Asia, Central Asia and in North America. They are concentrated in two regions: *the continental regions that had permafrost in the Pleistocene of northeast Europe, northwest Asia and southern Canada, which constitute by far the largest areas of Albeluvisols; *the loess and cover sand areas and old alluvial areas in moist temperate regions, such as France, central Belgium, the southeast of the Netherlands and the north and north-east of Germany. == See also == *Pedogenesis *Pedology (soil study) *Soil classification 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Albeluvisols」の詳細全文を読む スポンサード リンク
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