Page 123 - E-BOOK English

Profile features

The profile development of Plinthosols is typical of
A-(E)-BC, derived from strong weathering with subsequent
segregation of Fe (and Mn) and the formation of plinthite at a
depth of groundwater fluctuation or impeded surface water

drainage. Hardening of plinthite to petroplinthite or pisoliths
occurs depending on repeated wetting and drying. This may
take place during the intervals of the recession of a seasonally
fluctuating water table or after geological uplift of the terrain,

topsoil erosion, lowering of the groundwater level, increasing
drainage capacity, and/or climate change to drier conditions.

Environment and landforms

The environment of Plinthosols is frequently associated
with a hot-humid climate. The typical landforms for plinthite
development occur on plains or relatively flat areas, plateau,

terrace, including very gently sloping areas affecting the direction
of groundwater transport. These soils also occur in both dense
forests and dry grasslands, which the latter has a higher iron
accumulation. Under forested conditions, plinthite is developed
due to water contents, which trendily protect subsoils from

losing water toward the formation of hard layers. Therefore, shifting forest areas to grasslands
induces the hardening of plinthite in the subsoils.

Use and management

Plinthosols are categorized as soils having limitations or problematic soils for agriculture.
They present with continuous petroplinthite at shallow depth, limiting root penetration to the
extent that arable farming is not possible. Plinthosols have low amounts of fine earth fraction,

which causes naturally poor in nutrients and low content of available water. Moreover,
compacted layers of gravels reduce infiltration but increase bulk density, thereby resulting in
surface erosion easily. Petroplinthic materials can be cut to bricks, after irreversibly hardened.
They are used for construction. Pisoplinthic materials can be used for engineering, especially as
a surface material for road construction.

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