In the soil-forming regime, which one of the following occurs in a region where evapotranspiration exceeds precipitation significantly ?

The correct answer is A, Calcification. Where evapotranspiration is much greater than rainfall, water moves upward in the soil and calcium carbonate builds up near the surface.

In dry and semi-arid regions there is too little rain to wash soluble salts down and out of the soil. Instead, water rises through the soil by capillary action and evaporates, leaving calcium carbonate behind in a hard layer, called caliche or kankar. This process is called calcification, and it produces the soils of steppes, grasslands and deserts. In India, kankar layers are common in the dry parts of Rajasthan and the drier plains.

B is wrong because laterization needs heavy rainfall and high temperature, which wash out silica and leave iron and aluminium oxides behind. C is wrong because podsolization takes place in cool, wet climates under coniferous forests, where acids leach the upper layer. D is wrong because gleization happens in waterlogged soils with poor drainage and little oxygen.

Exam tip: dry climate gives calcification, hot wet climate gives laterization, cold wet climate gives podsolization, waterlogging gives gleization.