Soil
A natural body comprised of solids, liquids, and gases that forms on land surfaces and supports rooted plants.
Horizons
Distinguishable layers in soil resulting from additions, losses, transfers, and transformations of energy and matter.
Soil system storages
Components of soil that include organic matter, organisms, nutrients, minerals, air, and water.
Biological mixing
The transfer of material within soil through the activity of living organisms.
Leaching
The process of minerals dissolved in water moving through the soil.
Organic material inputs
Sources of organic matter in soil, such as leaf litter and precipitation.
Outputs
The removal of materials from soil, including plant uptake and soil erosion.
Transformations
Processes in soil such as decomposition, weathering, and nutrient cycling.
Soil structure
The arrangement and properties of different soil types, including sand, clay, and loam.
Primary productivity
The ability of soil to support plant growth based on its mineral and nutrient content, drainage, and water-holding capacity.
Upper limit of soil
The boundary between soil and air, shallow water, or live plants that have not decomposed.
Lower boundary of soil
The difficult-to-define separation between soil and the underlying non-soil material.
Inorganic components
Non-living elements of soil, including rock fragments, sand, silt, and clay.
Organic components
Living and dead organic matter in soil, including bacteria, fungi, earthworms, decaying plants, and animal remains.
Soil systems
Dynamic systems within larger ecosystems that can be simplified into storages, flows, transfers, and transformations.
Soil profiles
Distinct layers in soil that develop from long-term interactions and processes, transitioning from organic-rich to mineral-rich layers.
Factors influencing soil profiles
Elements such as climate, vegetation, parent material, and time that affect soil development.
Tropical rainforests
Ecosystems with thick, organic-rich top soils due to rapid decomposition and high biological activity.
Desert regions
Areas characterized by shallow, mineral-dominated soils with low organic matter input and minimal leaching.
Peat soils
Soils in boreal forests with thick layers of partially decomposed organic matter due to cold, wet conditions.
Prairie soils
Soils in the Great Plains known for deep, dark topsoil developed from organic matter accumulation over millennia.