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LECA is usually produced in different sizes and densities from 0.1 millimetres (0.004 in) up to 25 millimetres (1.0 in), commonly 0–4 mm, 4–10 mm, 10–25 mm and densities of 250, 280, 330, and 510 kg/m 3. LECA boulder is the biggest size of LECA with 100–500 mm size and 500 kg/m 3 density.
There are 12 soil orders (the top hierarchical level) in soil taxonomy. [2] [3] The names of the orders end with the suffix -sol. The criteria for the different soil orders include properties that reflect major differences in the genesis of soils. [4] The orders are: Alfisol – soils with aluminium and iron.
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):
where R is the rainfall erosivity factor, K is the soil erodibility, [3] [4] L and S are topographic factors representing length and slope, and C and P are cropping management factors. Other factors such as the stone content (referred as stoniness ), which acts as protection against soil erosion, are very significant in Mediterranean countries.
The Universal Soil Loss Equation (USLE) is a widely used mathematical model that describes soil erosion processes. [1]Erosion models play critical roles in soil and water resource conservation and nonpoint source pollution assessments, including: sediment load assessment and inventory, conservation planning and design for sediment control, and for the advancement of scientific understanding.
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.
Unweatherable parent materials – sand, iron oxide, aluminium oxide, kaolinite clay. Erosion – common on shoulder slopes; other kinds also important.; Deposition – continuous, repeated deposition of new parent materials by flood as diluvium, aeolian processes which means by wind, slope processes as colluvium, mudflows, other means.
Dispersion is a process that occurs in soils that are particularly vulnerable to erosion by water. In soil layers where clays are saturated with sodium ions ("sodic soils"), soil can break down very easily into fine particles and wash away. This can lead to a variety of soil and water quality problems, including: