Question

Which among the below statements about red soil of India is or are correct?
1. Red soils are rich in humus, lime and potash.
2. Red soils look yellow when it occurs in hydrated form.
3. The colour of the soil is red due to ferric oxide content.

Select the correct answer:

A) 1 only
B) 1 and 3 only
C) 2 and 3 only
D) 3 only

Answer 1

Hint:
Red soil develops during a temperate, warm, moist climate under deciduous or mixed forest. The forest has thin organic and organic-mineral layers lying over a yellowish-brown leached layer that rests over an illuvium red layer. Red soils are generally derived from crystalline rock.

Complete answer:
Red soils is known to be the third largest soil group of India covering a neighborhood of about 3.5 lakhs sq. km (10.6% of India's area) over the Peninsula from Tamil Nadu in the south to Bundelkhand in the north and Rajmahal hills in the east to Katchch in the west. It looks yellow in its hydrated form.

Content
Their colour comes due to oxide's present, occurring as thin coatings on the soil particles. The iron oxide is present as haematite or as hydrous ferric oxide and the color is red. While, when the same oxide is present within the hydrate form as limonite, the soil gets a yellow colour.

Characteristics
The texture of red soil varies from sand to clay, the bulk being loam. Apart from this its other characteristics include porous and friable structure, absence of lime, kankar and free carbonates, and little quantity of soluble salts. Red soils have very less percentage of lime, magnesia, phosphates, nitrogen, humus and potash. Intense leaching is a menace to these soils.

Types
(a) Red Loam Soil: This red loam soil forms due to the decomposition of granite, diorite rocks and gneiss charnockite. Apart from being cloddy and porous, it is also deficient in concretionary materials.
(b) Sandy Red Soil: This soil forms due to the disintegration of granite, granite gneiss, quartzite and sandstone.

Hence, the correct answer is option C.

Note:
 Some of the crops suitable for red soils are cotton, wheat, rice, pulses, millets, tobacco, oilseeds, potatoes, and fruits. The red soils are usually loamy by characteristic and therefore cannot retain water like the black soils.