What is lithic contact in soils?
Lithic contact: A lithic contact is a boundary between soil and continuous, coherent, underlying material. The underlying material considered here does not include diagnostic soil horizons such as duripans or petro- calcic horizons.
What is Cambic soil?
cambic horizon A weakly developed mineral soil horizon of the middle part (B horizon) of soil profiles, and one that has few distinguishing morphological characteristics except for evidence of weathering and sometimes of gleying. It is found in brown earths and gleys. It is a USDA term.
What is the Mollic horizon?
A surface horizon of mineral soil that is dark in colour, and relatively deep, and contains (dry weight) at least 1 per cent organic matter or 0.6 per cent organic carbon, the determination of either being acceptable.
What is a superactive soil?
The term “superactive” indicates a cation exchange capacity (by NH4OAC at pH 7) to clay (percent by weight) ratio of 0.60 or more. The term “isohyperthemic” refers to an average annual soil temperature of 22C (72F) or higher and an annual fluctuation of less than 5 degrees (C) at a depth of 50 cm.
What is Paralithic bedrock?
Paralithic material Partially weathered or weakly consolidated bedrock that requires no more than moderate force to be broken between one’s hands. Roots can penetrate only through cracks, not through the matrix (Soil Survey Staff, 2010).
What is lithic contact?
Lithic Contact A lithic contact is the boundary between soil and lithic materials. Except in Ruptic-Lithic subgroups, the underlying lithic materials must be virtually continuous within the limits of a pedon. The lithic materials have no cracks, or the spacing between cracks that roots can enter is 10 cm or more.
What is OXIC horizon?
oxic horizon A mineral subsoil horizon that is at least 30 cm thick and is identified by the almost complete absence of weatherable primary minerals, and by the presence of kaolinite clay, insoluble minerals such as quartz, hydrated oxides of iron and aluminium, small amounts of exchangeable bases, and low cation- …
What is a Mollic epipedon and what are its characteristics?
The mollic epipedon consists of mineral soil material. All component horizons or layers1 starting at the soil surface meet the following properties: a. Dominant color: (1) Value 3 or less, moist and 5 or less, dry; and (2) Chroma 3 or less moist; and b. Has 0.6 percent or more organic carbon; and c.
What is Histic epipedon?
A surface soil horizon, not less than 1 m in depth, high in organic carbon, and saturated with water for some part of the year. See also humus (2). The name is from the Greek histos, meaning ‘web’. From: histic epipedon in A Dictionary of Ecology » Subjects: Science and technology — Life Sciences.
How do Fragipans form?
Their formation can be attributed to compacting of soils by glaciers during the last ice age, physical ripening, permafrost processes, or other events that occurred in the pleistocene age. Some fragipans inherit their properties from buried soils called paleosols.