Which soil is fertile due to the presence of nitrate in Rajasthan?

Concept

Soil fertility depends on the supply of major plant nutrients, of which nitrogen is the most growth-limiting. When a soil naturally holds nitrogen in the readily-available nitrate (NO3-) form, plants can absorb it directly, so a nitrate-rich soil is comparatively fertile even in a dry region.

Applying it to Rajasthan

Among Rajasthan's soils, brown-sandy soil of the arid and semi-arid belt is the one specifically described as fertile because of its nitrate content. Its key features:

• Found across the arid/semi-arid districts (Pali, Nagaur, Sikar, Jhunjhunu, Jalore, Ajmer and adjoining areas).

• Holds nitrogen as nitrates and is also rich in phosphate, the two nutrients that drive crop growth.

• Supports crops such as bajra (pearl millet), mustard, cotton and maize; fertility rises towards the east and north-east.

Contrast with the other soils

• Red-sandy: drains fast, retains little moisture or nutrients - among the least fertile.

• Red-loamy: red from iron oxide, naturally low in fertility, needs amendment.

• Red-yellow: coloured by hydrated iron oxides, generally poor in nitrogen.

Hence the soil fertile due to the presence of nitrate in Rajasthan is brown-sandy soil.