2025年1月10日 · soil, the biologically active, porous medium that has developed in the uppermost layer of Earth’s crust. Soil is one of the principal substrata of life on Earth, serving as a reservoir of water and nutrients, as a medium for the filtration and breakdown of injurious wastes, and as a participant in the cycling of carbon and other elements through the global ecosystem.

2025年1月10日 · Soil - Formation, Composition, Structure: As stated at the beginning of this article, soils evolve under the action of biological, climatic, geologic, and topographic influences. The evolution of soils and their properties is called soil formation, and pedologists have identified five fundamental soil formation processes that influence soil properties. These five “state …

2024年12月24日 · horizon, a distinct layer of soil, approximately parallel with the land surface, whose properties develop from the combined actions of living organisms and percolating water. Because these actions can vary in their effects with increasing depth, it is often the case that more than one horizon exists beneath the surface of any soil area, at depths ranging from only a few …

Soils have a unique structural characteristic that distinguishes them from mere earth materials: a vertical sequence of layers produced by the combined actions of percolating waters and living organisms. These layers are called horizons and are designated A horizon, B horizon, C horizon, E horizon, O horizon, and R horizon.

2025年1月10日 · Central to both systems is the notion of diagnostic horizons, well-defined soil layers whose structure and. Soil - Texture, Structure, Composition: The two principal systems of soil classification in use today are the soil order system of the U.S. Soil Taxonomy and the soil group system, published as the World Reference Base for Soil Resources ...

Soil is a mixture of minerals and organic material that covers much of Earth’s surface. Minerals are bits of rock, and organic material is the remains of living things that have died.Soil is not as solid as rock. It has many small spaces, called pores, that hold water and air. In some places on Earth, a thin layer of soil only 6 inches (15 centimeters) thick lies on top of rock.

2025年1月10日 · Soil - Structure, Composition, Properties: The grain size of soil particles and the aggregate structures they form affect the ability of a soil to transport and retain water, air, and nutrients. Grain size is classified as clay if the particle diameter is less than 0.002 mm (0.0008 inch), as silt if it is between 0.002 mm (0.0008 inch) and 0.05 mm (0.002 inch), or as sand if it …

Other articles where soil layering is discussed: arboriculture: In soil layering, the shoots, or lower branches of the parent plant, are bent to the ground and covered with moist soil of good quality. When roots have developed, which may require a year or more, the branch is severed from the parent and transplanted. In…

Leaching, in geology, loss of soluble substances and colloids from the top layer of soil by percolating precipitation. The materials lost are carried downward (eluviated) and are generally redeposited (illuviated) in a lower layer. This transport results in a …

Among the wind-transported materials are loessial deposits (composed of packed layers of fine, powdery soil), which give rise to many of the productive prairie soils and to dune soils formed by blowing sands in desert and coastal regions. Alluvial materials are deposited by rivers and provide rich productive deltas, floodplains, and terraces ...