Alluvial Soil

1. Which of the following soils is deposited by rivers? [63rd B.P.S.C.(Pre) 2017]

Correct Answer: (c) Alluvial soil

Solution:Alluvial soil is formed by the silt left by the rivers. Alluvial soils are divided into two sub-categories-
(1) New alluvium or Khadar is formed in the flood plain of the river, where a new layer of soil is deposited every year during flood.
(2) Ancient Alluvium or Bangar: The condition of the soil is at some height away from the reach of flood.

2. Which of the following statements is/are true for alluvial soil? [Jharkhand P.C.S.(Pre) 2023]

L. Its sand content decreases from west to east.
II. They are in the form of Bhangar and Khadar.
III. This soil covers about 40 percent of the total area of the country.
IV. This soil is rich in potash and poor in phosphorus.

(a) I only
(b) I and II only
(c) I, II and III only
(d) I, II only

Correct Answer: (d) I, II only

Solution:Alluvial soil is ideal for horticultural crops. It consists of material deposited by rivers- during flood. As we move in- lands towards the river valleys, soil particles appear some what bigger in size. According to their grains/components soils are described on the basis of their age. According to their cage alluvial soils can be classified as old alluvial (Bangar and new alluvial (Khadar). Significatnly, sand con- tent of this soil decreases from west to east. Notably this soil covers 40 percent of the total area of the country. It is worth mentioning here that, mostly these soils contain adequate proportion of potash, phosphoric acid and lime which are ideal for the growth of sugarcane, paddy, wheat and other cereal and pulse crops.

3. In India, the largest soil group is found as: [M.P.P.C.S.(Pre) 2006]

(a) Red Soil
(b) Black Soil
(c) Sandy Soil
(d) Alluvial Soil

Correct Answer: (d) Alluvial Soil

Solution:Alluvial soil is the largest and the most important soil group of India. Covering about 11 lakh sq. km or about 33.5% of the total land area of the country, these soils contribute the largest share of our agricultural wealth. The widest occurrence of the Alluvial soils is in the Indo-Gangetic plain starting from Punjab in the West to West Bengal and Assam in the East. They are also found in deltas of Mahanadi, Godavari, Krishna and Cauvery, where they are called deltaic alluvium, Along the coast, they are known as coastal alluvium. Some alluvial soils are found in Narmada and Tapi (Tapti) valleys Geologically, the alluvium is divided into newer or younger Khadar and older Bhangar soils. Geographically, Black soils are spread over 5.46 lakh sq. km while the red soils occupy a vast area of about 8.7 lakh sq. km.

4. Which one of the following is the most widespread category of soils in India? [Chhattisgarh P.C.S.(Pre) 2017]

Correct Answer: (a) Alluvial soils

Solution:Alluvial soil is the largest and the most important soil group of India. Covering about 11 lakh sq. km or about 33.5% of the total land area of the country, these soils contribute the largest share of our agricultural wealth. The widest occurrence of the Alluvial soils is in the Indo-Gangetic plain starting from Punjab in the West to West Bengal and Assam in the East. They are also found in deltas of Mahanadi, Godavari, Krishna and Cauvery, where they are called deltaic alluvium, Along the coast, they are known as coastal alluvium. Some alluvial soils are found in Narmada and Tapi (Tapti) valleys Geologically, the alluvium is divided into newer or younger Khadar and older Bhangar soils. Geographically, Black soils are spread over 5.46 lakh sq. km while the red soils occupy a vast area of about 8.7 lakh sq. km.

5. Old Kachhari clay of Gangetic plain is called: [41st B.P.S.C.(Pre) 1996]

(a) Bhabar
(b) Bhangar
(c) Khadar
(d) Khonodolyte

Correct Answer: (b) Bhangar

Solution:Geologically, the alluvium of the great plain of India is divided into newer or younger khadar and older bhangar soils. Bhangar is found on the higher level beyond the reach of floods. Bhangar soil contains calcareous concretions and is generally pale reddish brown in color.

6. Which of the following types of soil has minimum water retention capacity? [Uttarakhand P.C.S.(Pre) 2003]

(a) Alluvial Sand soil
(b) Loamy Sand soil
(c) Clayey Loam soil
(d) Loamy soil

Correct Answer: (a) Alluvial Sand soil

Solution:Alluvial sand soil has minimum water retention capacity because soil with limited water holding capacity (i.e., sandy loam) reaches the saturation point much sooner than a soil with a higher water holding capacity (i.e., clay loam).

7. Which soil particles are present in loamy soils? [53rd to 55th B.P.S.C. (Pre) 2011]

(a) Sand particles
(b) Clay particles
(c) Silt particles
(d) All types of particles

Correct Answer: (d) All types of particles

Solution:Generally, Loam soil has 40% sand particles, 40% clay particles and 20% silt particles. Thus, option (d) is correct.

8. Choose the correct statement out of the four statements given regarding alluvial soil: [Chhattisgarh P.C.S.(Pre) 2020]

(a) This soil is found in about 14% portion of India's land surface
(b) Phosphoric acid is found in rich quantity in this soild
(c) This soil is also known by names such as Reh, Thur, Chopan
(d) This soil is not fertile

Correct Answer: (b) Phosphoric acid is found in rich quantity in this soild

Solution:Alluvial soils: They are the largest group covering about
11 lakh sq. km or about 33.5% of the total area. Alluvial
soils have Potash, Phosphoric acid and Alkalies in sufficient quantity. But the proportion of nitrogen is low. Alluvial soils as a whole are very fertile.
Reh, Thur, Chopan, Kallar, Rakar, Karl etc. are the local names for saline soils.

9. Which one of the following is the most productive soil in India? [U.P.R.O./A.R.O.(Pre) 2014]

(a) Red soil
(b) Black soil
(c) Alluvial soil
(d) Calcareous soil