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Calcareous (/ k æ l ˈ k ɛər i ə s /) is an adjective meaning "mostly or partly composed of calcium carbonate", in other words, containing lime or being chalky. The term is used in a wide variety of scientific disciplines.
Biological soil crusts are most often [3] composed of fungi, lichens, cyanobacteria, bryophytes, and algae in varying proportions. These organisms live in intimate association in the uppermost few millimeters of the soil surface, and are the biological basis for the formation of soil crusts.
Caliche is a mark of older landscapes. It generally occurs on or very near the surface. Where caliche layers originate at some depth from the soil surface, intact landscapes and buried landscapes are more likely than eroded surfaces to have caliche well below the soil surface.
Physical (as opposed to biological) soil crusts results from raindrop or trampling impacts. They are often hardened relative to uncrusted soil due to the accumulation of salts and silica. These can coexist with biological soil crusts, but have different ecological impact due to their difference in formation and composition.
Soil biology is the study of microbial and faunal activity and ecology in soil. Soil life , soil biota , soil fauna , or edaphon is a collective term that encompasses all organisms that spend a significant portion of their life cycle within a soil profile, or at the soil- litter interface.
Adequate moisture is necessary for effective potassium uptake; low soil water reduces K uptake by plant roots. Liming acidic soils can increase potassium retention in some soils by reducing leaching; [ 1 ] practices that increase soil organic matter can also increase potassium retention.
The Unified Soil Classification System (USCS) is a soil classification system used in engineering and geology to describe the texture and grain size of a soil. The classification system can be applied to most unconsolidated materials, and is represented by a two-letter symbol. Each letter is described below (with the exception of Pt):
Also called Indianite. A mineral from the lime-rich end of the plagioclase group of minerals. Anorthites are usually silicates of calcium and aluminium occurring in some basic igneous rocks, typically those produced by the contact metamorphism of impure calcareous sediments. anticline An arched fold in which the layers usually dip away from the fold axis. Contrast syncline. aphanic Having the ...