Climatic Soil Classification

Soil is a layer produced by the gradual weathering of the rock and covers the upper most surface. Development of soil depends on the several factors like Climate, Time, Topography, Parent rock, Biological activity etc.

The soil profile is the sequence of soil material found in the vertical section.

Climatic Soil Classification :-

To classify the soil scientists have used two important parameters dryness/wetness of the soil and the temperature of the region. Most common classification that is used , is the 12 soil orders of United States System. The all 12 soil orders end with “sol” which is a Latin word meaning “solum”. Most of the soils have Prefix that tells us about that particular soil. Ex :- “Molisol” , Mollis meaning soft.

Gelisols :- Gelisols comes form Latin word gelare – to freeze. It is the soil that are permanantly permafrost or contain evidence of permafrost near the soil surface. It is commonly fond in Arctic and Antarctic, as well as at extremely high elevations. This soil under gone cryoturbation process. Permafrosts also restricts the rooting depth of plants.
Histosols :- Histosols comes from Greek word histos – tissue. It is dominantly composed of organic material in their upper potion. The common names are bogs, moors, peat lands, muskegs, fens. These soils are formed when the organic matter decomposes more slowly than it accumulates due to a decrease in microbial decay rates. It mostly occurs in extremely wet areas or underwater and saturated all over the year. They are not suitable for roadways and may be highly acidic.
Spodosols :- Spodosols comes from Greek word spodos – wood ash. They formed when rain interacts with acidic vegetative litter like the conifer niddles to form organic acid. They often have dark surface underlain gray ash layer – reddish – rusty – black subsoil horizons. The produced acid dissolved Fe, Al, and organic matter in top soil. The Spodosols often develop in coarse soil under conifers vegetation in humid regions. They are acidic, low clay content and low fertility rate.

Andisols :- Andisol word comes from Japanese word ando – black soil. It typically forms from the weathering of volcanic materials such as ash, with minerals of poor crystal structures. These minerals have high capacity to hold both nutrients and water, which makes these soil fertile. They typically occurs in moderate to high rainfall and cool temperatures. They are highly weathered material that can be eroded easily.
Oxisols :- Oxysols term is taken from French word oxide – oxide. These are soil of tropical and subtropical regions, which are dominated by iron oxides, quartz, and highly weathered clay minerals such as kaolinite. These soils are found on the gently slopes and has been stable for long time. They have low fertility but can be productive through use of fertilizers and lime.
Vertisols :- Vertisols term is coined by a Latin word verto – turn. they are consists of soil that is shrinks and swells dramatically. When they are dry they form large cracks (>1m) deep and several inches wide. Water tends to pool on their surfaces when become wet. Vertisols are located in areas where the underlying rock material forms the expensive clay minerals.
Aridisols :- The term Aridisols comes from the Latin word aridus – dry. These are soils that occurs in climates that are too dry for ‘mesophytic’ plants. The climate resists the weathering process and you may find accumulation of salt, gypsum or carbonates which are found in hot and cold deserts worldwide. They are found in the dry valleys of Antarctica.
Ultisols :- Ultisols comes from Latin word ultimus – last. Ulticols are soils that have formed in humid area and are intensely weathered. They have all horizons, top soil, subsoil (acidic) and unaltered rock as well. Most nutrients are held in upper few cm’s. These soils are not productive but productivity can be nhanced by using fertilizers.
Mollisols :- Mollisols also comes from Latin word mollis – soft. They are prairie soil that have dark horizon, highly fertile and are rich in chemicals like Ca, Mg. Mollisols are often found with pronounced dry seasons.
Alfisols :- The term is coined by the term pedelfer -Al, Fe. These are similar to Ultisols but are less intensely weathered and less acidic. They are more fertile than Ultisols and are more common in forest vegetation with more fertility.

Inceptisols :- It is comes from Latin word inceptum – beginning. It exhibits moderate degree of soil development.
Entisols :- Entisols comes from recent – new. It exhibits very little or no soil dvelopment.

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