Page 62 - E-BOOK English

The representatives of Ferralsols in Thailand

Rhodic Ferralsols

Rhodic Ferralsols have a hue of reddish more

than 5YR with chroma (moist conditions) < 4 within
25-100 cm from the surface soil. These soils have

horizon thickness equal or thicker than 30 cm and
distribute more than 90 percent of the total area.

Pak Chong series (Pc) is a representative of
Rhodic Ferralsols. Pak Chong soils are formed from
residuum and local colluvium from limestone and

occur on the karst topography. They are found in the

lower part of Northeast of Thailand. Relief is undulating
which slopes range from 2-8 percent. Drainage is
well drained, permeability is moderate and surface

runoff is rapid to medium. They are very deep and

characterized by a dark reddish brown clay or silty
clay A horizon overlies red or dark red clay lower
kandic B horizon. Soil pH is moderately acid to neutral

(pH 6.0-7.0) at the surface layer and very strongly acid

to strongly acid (pH 4.5-5.5) in subsoil. Land use
limitation are low fertility and lack of water supply for
crop production.

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