CDS Geography · Indian Geography — Physical Features
Soils of India
The main soils of India, what each is rich and poor in, where each is found, and the soil orders of the modern classification.
Why this matters
Eight CDS questions from 2016 to 2026, four of them since 2023: 1 EASY, 6 MODERATE, 1 HARD. Most give three clues and ask you to name the soil, so learn each soil as a set of clues.
Concept 1 of 3: Alluvial and black soils
Alluvial soil is the silt rivers lay down, so it covers the great plains and the deltas. Black soil formed from the lava rocks of the Deccan; it is a sticky clay that holds water for a long time. These two soils carry most of India's farming.
Definition
Alluvial soil:
- Laid down by rivers; ranges from sandy loam to clay.
- Generally rich in potash and poor in phosphorus; has enough lime.
- Grouped by age: bhangar (older) and khadar (newer).
Black soil (regur, black cotton soil):
- Formed from the lava rocks of the Deccan; covers most of the Deccan plateau: Maharashtra, Madhya Pradesh, Gujarat.
- Rich in lime, iron, magnesia and alumina; poor in nitrogen, phosphorus and organic matter.
- Clayey, deep and impermeable; it holds moisture, so it suits rainfed cotton.
| Soil | Rich in | Poor in | Found in |
|---|---|---|---|
| Alluvial | Potash, lime | Phosphorus | Northern plains, river valleys and deltasQ CDS 2021 (I): rich in potash and poor in phosphorus. |
| Black (regur) | Lime, iron, magnesia, alumina | Nitrogen, phosphorus, organic matter | Deccan plateau: Maharashtra, Madhya Pradesh, GujaratQ CDS 2026 (I): the false statement said rainfed crops do not grow well in black soil. |
Practice this conceptself-check · 4 quick reps
The same idea in a real exam question:
CDS · 2021 · CDS (I) 2021 — General Knowledge · Q21Easy
Example 1 · Indian Geography — Physical Features · Soils of India
Identify the type of soil on the basis of the given characteristics :
1. They are rich in lime, iron, magnesia and alumina.
2. They are generally clayey, deep and impermeable.
3. They are mainly found in Maharashtra, Madhya Pradesh and Gujarat.
Select the correct answer from the given alternatives :
Impermeable helps, not hurts
Black soil is impermeable, and that is why it holds moisture and grows good rainfed crops such as cotton. A statement that rainfed crops do badly on it is false.
Alluvial is rich in potash, poor in phosphorus
The pairing is potash rich, phosphorus poor. CDS offered the reverse and both-rich options in 2021 (I).
Concept 2 of 3: Laterite, saline, arid and other soils
Each of these soils is shaped by its climate. Heavy rain washes laterite clean of most minerals; fierce evaporation leaves salt on top of saline soil; little rain keeps arid soil sandy and low in humus. Read the climate and you can name the soil.
Definition
The soils:
- Laterite: hot, very wet places; heavy rain washes out lime and silica and leaves iron and aluminium. Low in nitrogen and humus. Western Ghats, Kerala, Karnataka, hills of Odisha and the north-east.
- Saline (usar): sodium, potassium and magnesium salts; infertile; sandy to loamy; poor in nitrogen. Arid and semi-arid areas and waterlogged, swampy ground: western Gujarat, the eastern deltas, the Sundarbans.
- Arid: sandy, low in humus and nitrogen. Western Rajasthan.
- Red and yellow: red from iron spread through old crystalline rock, yellow when that iron is hydrated. Eastern and southern Deccan.
- Peaty: lots of humus and organic matter; wet, badly drained ground in coastal Kerala, Odisha and West Bengal.
| Soil | Clue | Found in |
|---|---|---|
| Laterite | Iron and aluminium; heavy rain washes out the rest | Western Ghats, Kerala, Karnataka, Odisha hills |
| Saline (usar) | Sodium, potassium and magnesium salts; infertile; poor in nitrogen | Western Gujarat, eastern deltas, SundarbansQ CDS 2025 (I): 'rich in nitrogen' was the false statement. |
| Arid | Sandy; low in humus and nitrogen | Western Rajasthan |
| Red and yellow | Iron in crystalline rock gives the colour | Eastern and southern Deccan |
| Peaty | Very rich in humus and organic matter | Coastal Kerala, Odisha, West Bengal |
Practice this conceptself-check · 4 quick reps
The same idea in a real exam question:
CDS · 2023 · CDS (II) 2023 — General Knowledge · Q60Moderate
Example 2 · Indian Geography — Physical Features · Soils of India
Identify the type of soil on the basis of given characteristics :
1. They contain a large proportion of sodium, potassium and magnesium, and thus, they are infertile.
2. Their structure ranges from sandy to loamy.
3. They are more widespread in western Gujarat, deltas of the eastern coast and in Sunderban areas of West Bengal.
Saline soil is not fertile
The salts in saline soil make it infertile, and it is poor in nitrogen. It forms both in dry areas and in waterlogged ground where evaporation leaves salt behind.
Concept 3 of 3: Soil orders (modern classification)
Scientists also sort soils into orders by how far their layers have developed. India's soils are mostly young: the two biggest orders, Inceptisols and Entisols, are soils whose layers have hardly formed yet.
Definition
Share of India's area (ICAR classification, as in the NCERT book):
- Inceptisols about 40%: young soils with weak layers; the largest.
- Entisols about 28%: very young soils, such as fresh river sand and silt.
- Alfisols about 14%.
- Vertisols about 9%: heavy clays that crack when dry, like black soil.
- Aridisols about 4%: desert soils.
| Soil order | Share of India | What it is |
|---|---|---|
| Inceptisols | About 40% | Young soils with weak layers |
| Entisols | About 28% | Very young soils |
| Alfisols | About 14% | More developed soils, with clay built up below the top layer |
| Vertisols | About 9% | Cracking clays, like black soil |
| Aridisols | About 4% | Desert soils |
Practice this conceptself-check · 3 quick reps
The same idea in a real exam question:
CDS · 2020 · CDS (II) 2020 — General Knowledge · Q11Hard
Example 3 · Indian Geography — Physical Features · Soils of India
The largest geographical area of India is covered by which one of the following types of soils?
Inceptisols, not Entisols, are the largest
Both are young soils, but Inceptisols (about 40%) cover more of India than Entisols (about 28%).
Summary — formulas & gotchas at a glance
A revision cheat-sheet for the formulas and gotchas above. Click any concept name to jump back to its full explanation.
Reference tables (3)
Alluvial and black soils2 rows
| Soil | Rich in | Poor in | Found in |
|---|---|---|---|
| Alluvial | Potash, lime | Phosphorus | Northern plains, river valleys and deltasQ CDS 2021 (I): rich in potash and poor in phosphorus. |
| Black (regur) | Lime, iron, magnesia, alumina | Nitrogen, phosphorus, organic matter | Deccan plateau: Maharashtra, Madhya Pradesh, GujaratQ CDS 2026 (I): the false statement said rainfed crops do not grow well in black soil. |
Laterite, saline, arid and other soils5 rows
| Soil | Clue | Found in |
|---|---|---|
| Laterite | Iron and aluminium; heavy rain washes out the rest | Western Ghats, Kerala, Karnataka, Odisha hills |
| Saline (usar) | Sodium, potassium and magnesium salts; infertile; poor in nitrogen | Western Gujarat, eastern deltas, SundarbansQ CDS 2025 (I): 'rich in nitrogen' was the false statement. |
| Arid | Sandy; low in humus and nitrogen | Western Rajasthan |
| Red and yellow | Iron in crystalline rock gives the colour | Eastern and southern Deccan |
| Peaty | Very rich in humus and organic matter | Coastal Kerala, Odisha, West Bengal |
Soil orders (modern classification)5 rows
| Soil order | Share of India | What it is |
|---|---|---|
| Inceptisols | About 40% | Young soils with weak layers |
| Entisols | About 28% | Very young soils |
| Alfisols | About 14% | More developed soils, with clay built up below the top layer |
| Vertisols | About 9% | Cracking clays, like black soil |
| Aridisols | About 4% | Desert soils |
Watch out for (4)
- Impermeable helps, not hurts→ Alluvial and black soils
- Alluvial is rich in potash, poor in phosphorus→ Alluvial and black soils
- Saline soil is not fertile→ Laterite, saline, arid and other soils
- Inceptisols, not Entisols, are the largest→ Soil orders (modern classification)
Test yourself on Indian Geography — Physical Features
20 past CDS questions from this chapter, timed at 20 minutes and marked the way the exam marks it. You see your score and every answer the moment you finish. Free to start.