"A soil horizon is a layer parallel to the soil surface whose physical, chemical, and biological characteristics differ from the layers above and beneath."
Study of the different layers of soil, including the organic layer (litter), topsoil, subsoil, and parent material, and their respective properties.
Soil formation: The process through which soil develops in nature.
Soil profile: A vertical section of soil that shows the distinct layers, or horizons, that make up the soil.
Soil texture: The proportion of different sized particles (sand, silt, clay) in the soil.
Soil structure: The way in which soil particles are arranged and held together.
Soil color: The hue, value, and chroma of soil.
Organic matter: The remains of dead plants and animals that have decomposed in the soil.
Mineral content: The various minerals and nutrients that are present in the soil.
Soil pH: The measure of acidity or alkalinity of the soil.
Soil fertility: The ability of soil to provide essential nutrients for plant growth.
Soil erosion: The wearing away of soil by wind, water, or other natural processes.
Soil pollutants: The presence of harmful substances in the soil.
Soil conservation: The practices that help to maintain the health and productivity of soil.
Soil classification: The categorization of soils based on their properties and characteristics.
Soil management: The techniques used to improve soil quality and productivity.
Soil testing: The analysis of soil to determine its properties and suitability for various uses.
O Horizon: The topmost layer of soil consisting of organic material, such as leaves, twigs, and decomposing plants or animals.
A Horizon: Also known as Topsoil, this is the layer below the O Horizon that is rich in organic matter and nutrients, including minerals, plant roots, insects, and small animals.
E Horizon: This is a light-colored soil layer that is often found between the A and B Horizons. It is formed by leaching and loss of minerals, leaving behind only sand, silt or clay.
B Horizon: Also known as Subsoil, this is the layer below the A Horizon that contains more clay, iron, and other minerals. It is often less fertile due to a lack of organic matter.
C Horizon: This layer is composed of weathered rock, gravel, or other geological materials, and is often the parent material of the soil. This horizon does not support much vegetation, except for some grasses and shrubs.
R Horizon: Also known as Bedrock, this is the bottom layer of the soil profile which is firmly attached to the Earth's crust.
"Horizons are defined in many cases by obvious physical features, mainly color and texture."
"These may be described both in absolute terms (particle size distribution for texture, for instance) and in terms relative to the surrounding material, i.e. 'coarser' or 'sandier' than the horizons above and below."
"The identified horizons are indicated with symbols, which are mostly used in a hierarchical way."
"Master horizons (main horizons) are indicated by capital letters."
"Suffixes, in the form of lowercase letters and figures, further differentiate the master horizons."
"No one system is more correct—as artificial constructs, their utility lies in their ability to accurately describe local conditions in a consistent manner."
"In most soil classification systems, horizons are used to define soil types."
"The German system uses entire horizon sequences for definition."
"Other systems pick out certain horizons, the 'diagnostic horizons,' for the definition."
"The WRB lists 40 diagnostic horizons."
"Diagnostic horizons are usually indicated with names, e.g., the 'cambic horizon' or the 'spodic horizon.'"
"In addition to these diagnostic horizons, some other soil characteristics may be needed to define a soil type."
"Some soils do not have a clear development of horizons."
"A soil horizon is a result of soil-forming processes (pedogenesis)."
"A soil horizon is a result of soil-forming processes (pedogenesis)."
"Layers that have not undergone such processes may be simply called 'layers'."
"Horizons are defined in many cases by obvious physical features, mainly color and texture."
"Horizons are defined in many cases by obvious physical features, mainly color and texture."
"Due to the different definitions of the horizon symbols, the systems cannot be mixed."