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from human activities such as deep cultivation, kitchen middens and the addition of organic manures etc. These horizons can usually be differentiated by the presence of artifacts, spade marks or by checking the agricultural history of the area.
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rich in organic matter. It is identified by its dark colour and structure. Normally it has a pH of less than 5.5 representing a
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in that it has a base saturation of < 50% on a weighted average throughout the depth of the horizon; and
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Similar thick, dark coloured, organic-rich, base-desaturated surface horizons occur in
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Soil organic carbon content of ≥ 0.6% throughout the thickness of mixed horizon; and
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and value ≤ 3 when moist and a value ≤ 5 when dry, both on slightly crushed samples.
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A thickness of ≥ 100 mm if resting directly on hard rock; ≥ 200 mm else.
54:(WRB), the umbric horizon is a diagnostic horizon. The diagnostic criteria are:
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Thick, dark coloured, surface soil horizon rich in organic matter
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Soil structure sufficiently strong that the horizon is not both
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is a rooting pattern whereby the roots tend to be horizontal.
110:"World Reference Base for Soil Resources 2014, Update 2015"
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115:. World Soil Resources Reports 106, FAO, Rome.
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35:of less than 50 percent. An indication for
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52:World Reference Base for Soil Resources
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27:) is a thick, dark coloured, surface
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160:. You can help Knowledge (XXG) by
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122:from the original on 2018-08-29
108:IUSS Working Group WRB (2015).
62:and hard or very hard when dry.
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44:anthropedogenic horizons
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201:Categories
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