Acrisol

In the FAO soil classification are Acrisole (Ac) red-colored, acid, by clay translocation ( Lessivierung ) dominated soils. They occur on old land surfaces of the wet tropics, subtropics and warm temperate climates. As a diagnostic horizon is used to, compared to the overlying tonangereicherte Bt horizon ( argic horizon ).

The typical horizon sequence is:

• Ah - humic topsoil
• E - Tonauswaschungshorizont ( eluvial )
• Bt1 - Tonanreicherungshorizont in the subsoil
• Bt2 - coined by Ferralitisierung underbody
• Cw - acidic bedrock ( deep weathered )

Subtypes

After features different types can be distinguished:

• Ferric Acrisols (ACF )
• Gleyic Acrisols (ACG )
• Plinthic Acrisols ( ACp )
• Humic Acrisols ( ACu )

Description

Acrisole have a low base saturation <50%. This is due to the usually low pH, whence the name (Latin acer acid) is derived. The long-lasting, strong weathering led to the dominance of low active clay minerals (low -activity clay ). Dominant clay minerals are kaolinite and halloysite, but also a low level of 3-layer clay minerals. The cation exchange capacity is found in parts of the Bt horizon < 240 mmolc / kg. The shade of color of the ground is due to the formation of the iron oxide hematite. In the subsoil occurs by the leaching of silica and the simultaneous accumulation of sesquioxides to Ferrallitisierung.

An agricultural use is limited in shifting possible because the nutrient content decreases rapidly and the unstable soil structure leads to capping. In plantation industry they are suitable for most aluminum - tolerant crops such as tea, rubber or oil palm.