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A soil survey should list the coefficient of linear extensibility (COLE) value. [2] Professional soil scientists can also analyze samples of a soil to determine its shrink-swell capacity. [2] Expansive soils will form large cracks, in roughly polygonal shapes, on the surface of the soil during dry periods. [3]
Soils are the product of climate, organisms and topography, acting on parent (geologic) material over time. Thus the great diversity of geologic materials, geomorphic processes, climatic conditions, biotic assemblages and land surface ages in the United States is responsible for the presence of an enormous variety of mineral and organic soils.
Expansive clays have an expanding crystal lattice in a 2:1 ratio; however, there are 2:1 non-expansive clays. [2] Mitigation of the effects of expansive clay on structures built in areas with expansive clays is a major challenge in geotechnical engineering. Some areas mitigate foundation cracking by watering around the foundation with a soaker ...
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:
Soil regeneration is the reformation of degraded soil through biological, chemical, and or physical processes. [ 2 ] When productivity declined in the low-clay soils of northern Thailand, farmers initially responded by adding organic matter from termite mounds , but this was unsustainable in the long-term.
Alkali, or alkaline, soils are clay soils with high pH (greater than 8.5), a poor soil structure and a low infiltration capacity. Often they have a hard calcareous layer at 0.5 to 1 metre depth. Alkali soils owe their unfavorable physico-chemical properties mainly to the dominating presence of sodium carbonate , which causes the soil to swell ...
In agriculture, soil compaction is a complex problem in which soil, crops, weather and machinery interact. External pressure due to the use of heavy machinery and inappropriate soil management can lead to the compaction of subsoil , creating impermeable layers within the soil that restrict water and nutrient cycles .
The use of soil tests, coupled with the corresponding provisions, can alleviate issues of nutrition and irrigation that can result from non porous Ultisol. [4] Soil tests help indicate the pH, and red clay soil typically has a low pH. [5] The addition of lime is used to help to increase the pH in soil and can help increase the pH in Ultisol as ...