Page 128 - E-BOOK English

Pisoplinthic Plinthosols

Pisoplinthic Plinthosols contain (or gravelly). A horizon overlying a yellowish red
concretions or nodules that are strongly or strong brown gravelly clay loam or clay argillic

cemented to indurated with Fe (and in some B horizon which in turn overlies a gray clay with
cases also with Mn) (hydr-)oxides starting ≤ 100 mottled C horizon. The loose ironstone layer

cm from the soil surface. formed as a continuous phase, thicker than 20

Phon Phisai series (Pp) is a representative cm up to 80 cm occurs within 50 cm depth
of Pisoplinthic Plinthosols. Phon Phisai soils are from the surface. Reaction is very strongly acid

formed from washed deposit over shale and/or to slightly acid (pH 4.5-6.5). They have root re-
siltstone and occur in middle part of peneplain. strictive layers, low effective soil volume, poor

These soils are typically found in northeast of nutrient status and low water holding capacity.
Thailand. Relief is undulating which slopes range In addition, they are also highly erodible.

from 2 to 6 percent. Drainage is moderately well
drained. Permeability is moderate over slow and

runoff is medium to rapid. They are shallow to
ironstone nodule layer and are characterized by

a very dark grayish brown sandy loam or loam

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