Page 15 - World Reference Base for Soil Resources of Thailand

Land Development Department Library

Diagnostic horizon Soil taxonomy
properties and materials
Gypsiric material** 5% or more gypsum

Histic horizon Histic epipedon

Hortic horizon Deep, P rich, anthropedogenic horizon

Hydragric horizon Redox features resulting from wet cultivation

Irragric horizon Light-coloured surface resulting from irrigation
Limnic material Limnic layer of coprogenous earth, diatomaceous earth and marl

Lithic discontinuity Lithologic discontinuity

Melanic horizon** Melanic epipedon
Mineral material Mineral material

Mollic horizon Mollic epipedon

Natric horizon Natric horizon

Nitic horizon Argillic horizon with shiny ped faces

Organic soil material Organic soil material
Permafrost** Permafrost

Petrocalcic horizon** Petrocalcic horizon

Petroduric horizon** Duripan

Petrogypsic horizon** Petrogypsic horizon
Petroplinthic horizon Petroferric contact

Pisoplinthic horizon 40% or more of hardened pisolitic laterite or ironstone

Plaggic horizon** Plaggen epipedon

Plinthic horizon Plinthite
Pretic horizon** -

Protocalcic properties** Petrocalcic horizon

Protovertic horizon Low prominent of shrink-swell cracks, slickensides or wedge-shaped peds

Reducing conditions Aquic conditions

Retic properties Interfingering of albic materials
Salic horizon Salic horizon

Secondary carbonates Identifiable secondary carbonates

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