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-illuvial horizon formed under cultivation -significant amounts of illuvial silt, clay and humus -directly below Ap horizon -thickness of 10cm or greater |
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-eluvial horizon that is lightly colored and low in clay and oxides (leaching) -1cm or greater -separate horizons that, if they were together, would meet requirements for a mollie epipedon or separate lamellae that together would be an argillic horizon |
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-anhydrite accumulation through neoformation and transformation -hue of 5Y, chroma (moist and dry) of 1 or 2, and value of 7 or 8 |
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-significantly higher percentage of phyllosilicate clay than overlying soil material -clay illuviation -total clay in illuvial horizon is greater by 1.2 times or more than the ratio in the alluvial horizon |
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-illuvial accumulation of calcium carbonates -15% more CaCO3 equivalent, and 5% identifiable secondary carbonates -"Petrocalcic" if secondary CaCO3 accumulated and cemented |
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-has not undergone enough illuviation to become argillic -sandy loam or finer (not loamy sand) -different color and structure from C horizon due to chemical transformations, or removals or a combination -colors that do not change on exposure to air -absence of rock structure |
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-silica-cemented subsurface horizon -can occur in conjunction with petrocalcic horizon -accumulation of silica (coatings, lenses, bridges, etc) -pan is cemented or indurated in more than 50% of the volume of some horizon |
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-evidence of pedogenesis -coarse prismatic, columnar or blocky structure -not effervescent -layer is 60% or more of the volume, a firm or firmer rupture-resistence class, a brittle manner of failure at or near field capacity and virtually no roots |
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-degredation of an argillic, kandic or natric horizon from which clay and free iron oxides are removed -eluvial part that constitutes 15-85% (by vol) of glossic horizon |
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-accumulated or transformed gypsum -not cemented by gypsum (with or without cementing agent) -5% or more of gypsum -"Petrogypsic" if secondary gypsum has accumulated or been transformed and cemented (40% or more gypsum) |
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-accumulation of Fe and Al oxides and kaolinite clays -low cation holding capacity -product of intense weathering -loamy VF sand or finer |
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-like argillic with the addition of sodium ->15% exchangeable sodium -columnar structure -evidence of clay illuviation |
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-highly weathered subsurface very high in Al and Fe -humid and subtropical environments -10% weatherable minerals in sand, silt or clay, all other minerals have weathered to elements -does not have antic soil properties -30 cm or greater -sandy loam or finer |
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cemented by iron (or iron and manganese) and organic matter |
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accumulation of salts more soluble than gypsum |
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-dark subsurface horizon that formed under free drainage -illuvial humus that is neither associated with Al nor dispersed by Na -does not have high CEC in its clay -lower color value and/or chroma than overlying horizon |
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Definition
-illuvial layer with 85% or more spodic materials (greater than 2.5 cm) -spodic materials are colloidal organic matter, aluminum oxide and iron -underlies O, A or E horizon -common in leached forests of cool humid climates -on sandy PM |
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