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Subsoil layer. Subsoil is the layer of soil under the topsoil on the surface of the ground. Like topsoil, it is composed of a variable mixture of small particles such as sand, silt and clay, but with a much lower percentage of organic matter and humus. The subsoil is labeled the B Horizon in most soil mapping systems.
An Acrisol is a Reference Soil Group of the World Reference Base for Soil Resources (WRB). [1] It has a clay-rich subsoil and is associated with humid, tropical climates, such as those found in Brazil, and often supports forested areas. [2]
Also required is sufficient age to exhibit subsoil weathering and development. Limited leaching in aridisols often results in one or more subsurface soil horizons in which suspended or dissolved minerals have been deposited: silicate clays, sodium, calcium carbonate, gypsum, or soluble salts.
The solum (plural, sola) in soil science consists of the surface and subsoil layers that have undergone the same soil forming conditions. The base of the solum is the relatively unweathered parent material. Solum and soils are not synonymous. Some soils include layers that are not affected by soil formation. These layers are not part of the solum.
USDA soil taxonomy (ST) developed by the United States Department of Agriculture and the National Cooperative Soil Survey provides an elaborate classification of soil types according to several parameters (most commonly their properties) and in several levels: Order, Suborder, Great Group, Subgroup, Family, and Series.
Soil scientists use the capital letters O, A, B, C, and E to identify the master horizons, and lowercase letters for distinctions of these horizons. Most soils have three major horizons—the surface horizon (A), the subsoil (B), and the substratum (C). Some soils have an organic horizon (O) on the surface, but this horizon can also be buried.
Haplic Planosol profile near Abiy Addi in Ethiopia Distribution of Planosols Soil profile of a Eutric Planosol. A Planosol in the World Reference Base for Soil Resources [1] is a soil with a light-coloured, coarse-textured, surface horizon that shows signs of periodic water stagnation and abruptly overlies a dense, slowly permeable subsoil with significantly more clay than the surface horizon.
Soil is a major component of the Earth's ecosystem.The world's ecosystems are impacted in far-reaching ways by the processes carried out in the soil, with effects ranging from ozone depletion and global warming to rainforest destruction and water pollution.