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  2. Gelisol - Wikipedia

    en.wikipedia.org/wiki/Gelisol

    They are soils of very cold climates which are defined as containing permafrost within two meters (6 ft 7 in) of the soil surface. The word "Gelisol" comes from the Latin gelare meaning "to freeze", a reference to the process of cryoturbation that occurs from the alternating thawing and freezing characteristic of Gelisols.

  3. USDA soil taxonomy - Wikipedia

    en.wikipedia.org/wiki/USDA_soil_taxonomy

    Vertisols: Usually mollic epipedon; high in shrinking and swelling clays; >30% clay to a depth of 50 cm; deep cracks (called gilgai) form when soil dries; form from parent material high in clay (e.g., shales, basins, exposed Bt horizons of old soils); 2.4% of global and 1.7% of U.S. ice-free land.

  4. Gleysol - Wikipedia

    en.wikipedia.org/wiki/Gleysol

    Distribution of Gleysols. A gleysol or gley soil is a hydric soil that unless drained is saturated with groundwater for long enough to develop a characteristic gleyic colour pattern.

  5. Percolation test - Wikipedia

    en.wikipedia.org/wiki/Percolation_test

    A percolation test consists of digging one or more holes in the soil of the proposed leach field to a specified depth, presoaking the holes by maintaining a high water level in the holes, then running the test by filling the holes to a specific level and timing the drop of the water level as the water percolates into the surrounding soil.

  6. Secchi disk - Wikipedia

    en.wikipedia.org/wiki/Secchi_disk

    Different kinds of Secchi disks. A marine style on the left and the freshwater version on the right. The Secchi depth is reached when the reflectance equals the intensity of light backscattered from the water. 1.7 divided by this depth in metres yields an attenuation coefficient (also called an extinction coefficient), for the available light averaged over the Secchi disk depth.

  7. Drainage equation - Wikipedia

    en.wikipedia.org/wiki/Drainage_equation

    the permissible long term average depth of the water table (Dw) on the basis of agricultural drainage criteria; the soil's hydraulic conductivity (Ka and Kb) by measurements; the depth of the bottom of the aquifer (Di) the design drain spacing (L) can be found from the equation in dependence of the drain depth (Dd) and drain radius (r ...

  8. Entisol - Wikipedia

    en.wikipedia.org/wiki/Entisol

    Entisols are common in the paleopedological record ever since the Silurian; however, unlike other soil orders (oxisol, ultisol, gelisol, etc) they do not have value as indicators of climate. Orthents may, in some cases, be indicative of an extremely ancient landscape with very little soil formation (i.e., Australia today).

  9. Mollisol - Wikipedia

    en.wikipedia.org/wiki/Mollisol

    Mollisol is a soil type which has deep, high organic matter, nutrient-enriched surface soil , typically between 60 and 80 cm (24-31 in) in depth. This fertile surface horizon, called a mollic epipedon, is the defining diagnostic feature of Mollisols.