Search results
The soil is arranged in layers or horizons during its formation. These layers or horizons are known as the soil profile. It is the vertical section of the soil that is exposed by a soil pit. The layers of soil can easily be identified by the soil colour and size of soil particles. The different layers of soil are:
- Minerals In The Soil And Soil Pollution
Soil pollution led to infertility by killing microorganisms...
- Soil Teeming
The soil profile is a tool utilized in nutrient management....
- Types of Soil
2. State the characteristics of sandy soil. Sandy soil...
- Preparation of Soil for Agriculture
What is Soil Profile? Soil preparation. Ploughing;...
- Water Absorption in Soil
Soil and its Formation. The definition of soil is something...
- What Is Soil
Also Read: Soil Profile. Composition of Soil. The soil is...
- Minerals In The Soil And Soil Pollution
Dec 13, 2023 · A Soil Profile is a vertical section of the soil that shows its various layers or horizons. Over time, as soil matures, layers (or horizons) form a soil profile. A model of soil profile explains the horizons in a better manner. These horizons, from top to bottom, are labeled as O, A, E, B, and C horizons.
- Overview
- Soil horizons
- Pedons and polypedons
Soil is the biologically active and porous medium that has developed in the uppermost layer of Earth’s crust. It serves as the reservoir of water and nutrients and a medium for the filtration and breakdown of injurious wastes. It also helps in the cycling of carbon and other elements through the global ecosystem.
What are the grain sizes in soil?
The grain size of soil particles are categorized into three groups: clay, silt, and sand. Clay measures less than 0.002 mm (0.0008 inch) in diameter, silt is between 0.002 mm (0.0008 inch) and 0.05 mm (0.002 inch), and sand is between 0.05 mm (0.002 inch) and 2 mm (0.08 inch).
What are the five factors of soil formation?
The evolution of soils and their properties is called soil formation, and according to pedologists, five fundamental soil formation processes influence soil properties. These five “state factors” are parent material, topography, climate, organisms, and time.
What are the layers of soil?
Soils differ widely in their properties because of geologic and climatic variation over distance and time. Even a simple property, such as the soil thickness, can range from a few centimetres to many metres, depending on the intensity and duration of weathering, episodes of soil deposition and erosion, and the patterns of landscape evolution. Nevertheless, in spite of this variability, soils have a unique structural characteristic that distinguishes them from mere earth materials and serves as a basis for their classification: a vertical sequence of layers produced by the combined actions of percolating waters and living organisms.
These layers are called horizons, and the full vertical sequence of horizons constitutes the soil profile (see the figure). Soil horizons are defined by features that reflect soil-forming processes. For instance, the uppermost soil layer (not including surface litter) is termed the A horizon. This is a weathered layer that contains an accumulation of humus (decomposed, dark-coloured, carbon-rich matter) and microbial biomass that is mixed with small-grained minerals to form aggregate structures.
Below A lies the B horizon. In mature soils this layer is characterized by an accumulation of clay (small particles less than 0.002 mm [0.00008 inch] in diameter) that has either been deposited out of percolating waters or precipitated by chemical processes involving dissolved products of weathering. Clay endows B horizons with an array of diverse structural features (blocks, columns, and prisms) formed from small clay particles that can be linked together in various configurations as the horizon evolves.
Are you a student? Get Britannica Premium for only 24.95 - a 67% discount!
Learn More
Below the A and B horizons is the C horizon, a zone of little or no humus accumulation or soil structure development. The C horizon often is composed of unconsolidated parent material from which the A and B horizons have formed. It lacks the characteristic features of the A and B horizons and may be either relatively unweathered or deeply weathered. At some depth below the A, B, and C horizons lies consolidated rock, which makes up the R horizon.
Soils are natural elements of weathered landscapes whose properties may vary spatially. For scientific study, however, it is useful to think of soils as unions of modules known as pedons. A pedon is the smallest element of landscape that can be called soil. Its depth limit is the somewhat arbitrary boundary between soil and “not soil” (e.g., bedrock). Its lateral dimensions must be large enough to permit a study of any horizons present—in general, an area from 1 to 10 square metres (10 to 100 square feet), taking into account that a horizon may be variable in thickness or even discontinuous. Wherever horizons are cyclic and recur at intervals of 2 to 7 metres (7 to 23 feet), the pedon includes one-half the cycle. Thus, each pedon includes the range of horizon variability that occurs within small areas. Wherever the cycle is less than 2 metres, or wherever all horizons are continuous and of uniform thickness, the pedon has an area of 1 square metre.
Soils are encountered on the landscape as groups of similar pedons, called polypedons, that contain sufficient area to qualify as a taxonomic unit. Polypedons are bounded from below by “not soil” and laterally by pedons of dissimilar characteristics.
- Garrison Sposito
Sep 17, 2024 · The soil profile is one of the most significant components of terrestrial ecosystems, often overlooked yet playing a crucial role in sustaining life on Earth. Soil is not just dirt; it is a dynamic, living system that supports plant life, regulates water, and acts as a medium for microbial processes.
Feb 19, 2022 · Continued weathering and soil horizon development process leads to the development of a soil profile, the vertical display of soil horizons. Watch the typical progression of a soil profile then read the description below of a generic, fully developed soil. Figure 11.4.1 11.4. 1: A Typical Soil Profile (after Oberlander & Muller, 1987)
Apr 27, 2024 · The particular compositional, structural and chemical composition of the soil depends on the various factors that influence soil formation. This page titled 16.4: Soil Profiles is shared under a CC BY-NC-SA 4.0 license and was authored, remixed, and/or curated by Arnaud Temme, Kansas State University ( The Physical Environment ) via source content that was edited to the style and standards of ...
People also ask
What is soil profile?
Why is soil profile important in biogeography?
What are horizons in a soil profile?
How do you know if a soil profile is fully developed?
How is soil arranged in layers or horizons?
How do soil profiles change across different environments?
Definition. A soil profile is a vertical section of the soil that showcases all its distinct layers, or horizons, from the surface down to the bedrock. Each layer in the profile has unique characteristics, such as color, texture, and composition, reflecting the processes of weathering, erosion, and deposition that have shaped it over time.
