Brown lowland soil - Brown lowland soil

…Soils derived from silicate-based consolidated rocks are called consolidated lithic soils, while those derived from unconsolidated rocks such as dune sand, volcanic ash, and loess are called unconsolidated lithic soils. Soils that are formed from parent materials that are formed when rivers erode and transport rocks and soil from upstream areas and deposit them in floodplains downstream are generally called alluvial soils, and soil types that fall under this category include brown lowland soils and gray lowland soils. Brown lowland soils are distributed in places with low groundwater levels and good drainage, such as low-lying river terraces, alluvial fans, natural levees, and relatively stable alluvial surfaces some distance from the riverbed in alluvial plains. …

*Some of the terminology used to describe "brown lowland soil" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…ケイ酸塩質の固結した岩石に由来するものを固結岩屑土，砂丘砂，火山灰，レスなどの非固結の岩石に由来するものを非固結岩屑土という。　河川が上流地域の岩石や土壌を浸食し運搬してきた物質が，下流のはんらん原などに堆積してできた母材から生成する土壌は一般に沖積土壌といわれるが，これに含まれる土壌型には褐色低地土，灰色低地土などがある。褐色低地土は沖積平野の低位河岸段丘，扇状地，自然堤防，河床からやや離れた比較的安定な沖積面などの地下水位の低い排水のよい場所に分布している。…

※「褐色低地土」について言及している用語解説の一部を掲載しています。

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