10 points on laterite soil , arid soil and forest soil
Answers
Arid soil can be classified as a group of soils belonging to the aridisol order of USDA classification. The name as derived from Latin “Aridus” itself depicts the dry climate responsible for the development of the order.
The order Aridisol is limited to most arid portion of Thar desert of Rajasthan in India. The order is predominant in the major deserts around the world namely Sahara,Kalahari etc.Like most others orders of soil classification Aridisols are also characterized with some distinct features .
Lower concentration of SOM: In case of arid soil ,the Organic matter content is too low about less than 0.1% because of the rapid oxidation of soil organic matter that causes depletion at a faster rate as compared to it's natural replenishment.
Salinization: Acculation of soluble salts in the surface and subsurface layer mostly occurs in the premonsoon season because of high PET or Potential Evapotranspiration as against lower amount and very erratic precipitation.
Calcification: Due to limited leaching of soil constituents accumulation of layers of calcium carbonate occurs in the lower soil layers termed as calcification that shows cementation of soil seperates.
Gypsification: Due to limited leaching , accumulation of gypsum occurs in sublayers of soils.
Natric horizon formation: in some cases a layer of high Exchangeable sodium percentage( ESP ) is formed.
From edaphological point of view,arid soils are very much unsuitable for crop production except for a few xerophytic vegetation.
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Laterite is a soil and rock type rich in iron and aluminium and is commonly considered to have formed in hot and wet tropical areas. Nearly all laterites are of rusty-red coloration, because of high iron oxide content. They develop by intensive and prolonged weathering of the underlying parent rock. Tropical weathering (laterization) is a prolonged process of chemical weathering which produces a wide variety in the thickness, grade, chemistry and ore mineralogy of the resulting soils. The majority of the land area containing laterites is between the tropics of Cancer and Capricorn.
Laterite has commonly been referred to as a soil type as well as being a rock type. This and further variation in the modes of conceptualizing about laterite (e.g. also as a complete weathering profile or theory about weathering) has led to calls for the term to be abandoned altogether. At least a few researchers specializing in regolith development have considered that hopeless confusion has evolved around the name. There is no likelihood, however, that the name will ever be abandoned; for material that looks highly similar to the Indian laterite occurs abundantly worldwide, and it is reasonable to call such material laterite.