Q1. Which of the following soil types is primarily formed due to deposition by rivers and is characterized by annual renewal of fertility?
(a) Black Soil
(b) Red Soil
(c) Alluvial Soil
(d) Laterite Soil
Answer: (c) Alluvial Soil
Explanation:
- Formation: Deposited by major river systems (Indus–Ganga–Brahmaputra) through fluvial processes.
- Annual renewal: Floods bring fresh silt (alluvium) → replenishes nutrients → sustains high fertility.
- Nutrient profile: Rich in potash & humus, relatively deficient in phosphorus.
- Extent: Covers ~45.6% of India → agricultural backbone (rice–wheat system).
Q2. Assertion (A): Black soil is considered ideal for cotton cultivation.
Reason (R): Black soil has high clay content, excellent moisture retention capacity, and is rich in lime and iron.
(a) Both A and R are true and R is the correct explanation of A
(b) Both A and R are true but R is not the correct explanation of A
(c) A is true but R is false
(d) A is false but R is true
Answer: (a)
Explanation:
- Assertion: Correct → Black soil is also called Regur / Black Cotton Soil.
- Reason: Correct and explanatory:
- High clay (>60%) → retains moisture → crucial for cotton (long growing season).
- Shrink–swell property → improves aeration (self-ploughing).
- Chemical composition: Rich in lime, iron, magnesium → supports crop growth.
- Origin: Derived from Deccan Trap basalt.
Q3. A farmer in the Western Ghats wants to cultivate plantation crops that thrive in acidic, leached soils rich in iron and aluminium oxides. Which soil is most suitable?
(a) Alluvial Soil
(b) Red Soil
(c) Laterite Soil
(d) Forest Soil
Answer: (c) Laterite Soil
Explanation:
- Formation: Intense leaching under high rainfall and temperature → removal of silica → concentration of Fe & Al oxides.
- Nature:
- Acidic, nutrient-poor (deficient in NPK)
- Porous, well-drained → suitable for plantation crops
- Geography: Western Ghats, Eastern Ghats, NE India
- Crops: Tea, coffee, rubber, cashew
Q4. Consider the following soil types:
- Black Soil
- Red Soil
- Laterite Soil
Which of the above is/are known for poor nitrogen, phosphorus, and potassium (NPK) content?
(a) 1 only
(b) 2 and 3 only
(c) 1, 2 and 3
(d) 1 and 3 only
Answer: (b) 2 and 3 only
Explanation:
- Red Soil:
- Deficient in nitrogen, phosphorus, humus → low fertility
- Laterite Soil:
- Strongly leached → removal of bases → poor in NPK
- Black Soil:
- Deficient mainly in nitrogen & phosphorus, but relatively better in potassium and micronutrients
Q5. ‘Reh’, ‘Usar’, and ‘Kallar’ are local names associated with which soil type found in Punjab, Haryana, and Uttar Pradesh?
(a) Laterite Soil
(b) Peaty & Marshy Soil
(c) Saline & Alkaline Soil
(d) Desert Soil
Answer: (c) Saline & Alkaline Soil
Explanation:
- Nature: High concentration of soluble salts (Na, Mg, Ca) → forms white crust.
- Causes:
- Poor drainage
- High evaporation → salt accumulation
- Irrigation mismanagement
- Impact:
- Reduces soil permeability
- Toxic to crops → low productivity
- Reclamation:
- Gypsum application + proper drainage + leaching
