Page 95 - E-BOOK English

Kastanozems

Definition

Kastanozems are the soils having mollic and calcic horizons or those horizons with
protocalcic properties within 50 cm A moist chroma of > 2 is found at a depth of at least
20 cm Accumulations of secondary carbonates occur within 100 cm from the surface with no

diagnostic horizons other than an argic, cambic, gypsic, or vertic horizon.

Distribution

Kastanozems are of 2,550 million rais worldwide. They mostly occur on the southern
steppes of Ukraine, southern Russia, Kazakhstan, Mongolia, United States, Canada, Mexico,

northern Argentina, Paraguay, and southeastern Bolivia.
In Thailand, the total extent of Kastanozems is about 3.7 million rais. They are
commonly found in the central mountain region and the western part of Thailand, in Nakhon

Sawan, Phetchabun, Lopburi, Saraburi, and Kanchanaburi provinces, followed by the northeast,
the north, and a little in the upper east, respectively.

Formation

Kastanozems are generally formed on grasslands. The grass biomass provides an

organic input that causes dark-brown soils with a brown mollic horizon. This process is called
melanization, which typically contains 2 to 4 percent organic matter. In the middle of the profile,
accumulations of secondary carbonates or carbonate concretions are found, but at a shallower

depth than in the Chernozems.

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