Soil Horizons


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Soil Horizons

 

layers created as a result of natural differentiation during soil formation; they are also called genetic horizons. All the soil horizons together form the soil profile. Each horizon is more or less homogeneous in granulometric, mineral and chemical composition, physical properties, texture, and color. It can also be divided into subhorizons. Soil horizons are designated by the letters A, B, and C. A designates the horizon of humus accumulation and also the eluvial horizon; B the illuvial, or metamorphic horizon; and C the parent material. The A horizon in turn is subdivided into A0, indicating forest litter or steppe matting; A1, the humus subhorizon; and A2, the podzolic subhorizon. An Ap horizon is formed in plowed soils.

References in periodicals archive ?
For this purpose, the organic carbon concentration which was determined by analysis for each soil horizon was multiplied by fine soil volume weight (< 2 mm) and converted to values in unit volume.
Both of these soil landscapes contain at least one soil horizon with low permeability.
Woody species, and especially trees, are able to access water from deeper soil horizons than are grasses, leading to tree-grass coexistence via niche separation, especially on more-stressful, moisture-limited southern aspects (Breshears and Barnes, 1999; Sankaran et al.
The goals were to 1) determine if the factors can be interpreted according to some geochemical association, and 2) determine if factors vary within and between willow leaves and soil horizons.
Of these, Profiles 2, 7, and 10 have soil horizons with DI 8, which approaches an infiltration rate of 0.
Collectively, the soil horizons that have undergone the same soil forming conditions are referred to as the solum (Fig.
The proportion of rock fragments in soil horizons was estimated by volume.
At each field site, soil horizon thicknesses were noted and the soil horizon colors were determined using a Munsell Soil Color chart.
Identify the layers in soil horizons and briefly discuss the properties of each.
If sufficiently stable, these materials may form a soil as defined in Soil Taxonomy as a three-dimensional natural body composed of mineral and organic materials that is able to support rooted vegetation or that forms soil horizons through soil formation processes (Soil Survey Staff 1999).
The formed genetic soil horizons (A-AC) and initial detritus were studied, described and sampled in fifteen reference profiles to a depth of 20-35 cm where signs of evident soil formation were already disappeared and unchanged detritus was clearly distinguished.