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Jan 1, 2020 · The clay content (mean CV of 8%) varied more than sand (mean CV of 6%) and silt contents (mean CV of 4%). In the A horizon, the mean CVs were 40% for soil organic carbon (SOC) but only 7% for bulk density. The variation of most soil properties within the A horizon was lower than that in the B and C horizons (Fig. 14).
- A.E. Hartemink, Y. Zhang, J.G. Bockheim, N. Curi, S.H.G. Silva, J. Grauer-Gray, David J. Lowe, P. Kr...
- 2020
Understanding soil morphology and horizon nomenclature is essential for effectively describing, classifying, and communicating information about soils. By following the steps outlined in this lecture and applying the master horizon and suffix designations, soil scientists and other professionals can create standardized, informative soil profile descriptions.
If any part of an eluvial horizon remains and there is no lithologic discontinuity between it and the Bt horizon, the Bt horizon contains more total clay than the eluvial horizon as follows: If any part of the eluvial horizon has less than 15% total clay in the fine earth fraction (≤2 mm ), the Bt horizon must contain at least 3% more clay (e.g., Ae 10% clay; Bt minimum 13% clay).
Certain soil horizons or horizon sequences are the result of hydrologic processes within the soil and serve as evidence of the magnitude and direction of water movement within the soil. Eluvial and illuvial processes translocate silicate clay minerals, iron oxides, humus, carbonates, and other soil constituents.
Pedon – smallest three-dimensional unit that displays the full range of properties characteristic of a given soil. (1-10 m2 of area) - the fundamental unit of soil classification. Polypedon – group of closely associated pedons in the field. Soil Series – class of soils world-wide which share a common suite of soil profile properties.
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- 17
The Bt horizon (22 –68cm) had subangular blocky structure and silty clay loam texture, with dark yellowish brown (10YR 4/4, moist) and light yellowish brown (10YR 6/4 dry) colors. The 2Bw horizon (68–100cm) had subangular. Fig. 16 Soil property variation in horizons of a Mollisol from south central Wisconsin, USA.
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What is a horizon nomenclature?
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Horizon nomenclature: O horizon: O horizons occur at the soil surface and are made up mainly of organic material. They are uncommon in Australian soils but are found in rainforests where decomposing leaf litter accumulates. A horizon: A horizons are surface mineral horizons that are darkened by an accumulation of organic matter. A2 horizon:
