Soil Classification Diagnostic Surface Horizons Soil Taxonomy Epi meaning over or upon Pedon meaning soil Anthropic Histic Formed under long continued use by man Thin horizon of peat or muck usually either place of residence or as for growing crops High in Phosphorus Europe saturated with water 30 days Organic carbon is high 12 Mollic Dark colored thick soft mineral surface dominated by divalent cations Moderate or strong structure Color value 3 5 moist 5 5 dry 3 5 chroma High base saturation 50 Greater than 25 cm or 1 3 of solum 1 Umbric Plaggen Similar to Mollic except base saturation Man made surface layer 50 cm Ochric Diagnostic subsurface horizons 50 thick produced by long continued manuring Europe Too light in color too high in chroma Too low in organic matter or Too thin to qualify as one of the other diagnostic surface horizons epipedons Agric Albic Formed under cultivation contains illuvial Color of mineral grains clay and Fe and Al silt clay and humus oxides removed 2 Argillic Illuvial horizon where clays silicate have accumulated Calcic Secondary accumulation of CaCO3 or MgCO3 arid Cambic Altered non illuvial insufficient clay movement to be an argillic Duripan Fragipan Indurated cemented by silica or Fe oxides Low organic matter high bulk density or Ca CO3 or Al silicate arid or semi arid hard brittle cemented when dry 3 Gypsic Natric Gypsum CaSO4 2H2O present Argillic plus high Na Oxic Petrocalcic Intense weathering tropical hydrated Harden calcic cemented pores plugged oxides of Fe or Al 1 1 clay Massive Petrogypsic Placic Harden gypsic cemented pores plugged Thin black or dark reddish brown cement pan Fe Fe Mg or Fe C 4 Salic Sombric Thick with secondary salts Illuvial humus low CEC low base Spodic Sulfuric Illuvial organic matter Al Fe pH 3 5 Jarosite mottles Organic and sulfide rick saturation tropical Alfisols High Nutrient Soils Argillic clay accumulation high base saturation 5 Andisols Volcanic Soils Aridisols Desert Soils Dry arid 6 Entisols New Soils Recent little or no change of original parent material Gelisols Permafrost 7
View Full Document
Unlocking...