India: Monsoon, Soils and Natural Vegetation
India: Monsoon, Soils and Natural Vegetation
India's climate is a monsoon climate: seasonal winds reverse direction and bring most of the year's rain in four months. Soils and forests follow this rainfall. NTPC asks the monsoon's branches and mechanisms, which soil is found where and suits which crop, and the types of forests.
1. The Monsoon
| Item | Facts |
|---|---|
| South-west monsoon | June to September; two branches: Arabian Sea branch and Bay of Bengal branch; onset over Kerala around 1 June |
| North-east (retreating) monsoon | October to December; rain on the Tamil Nadu coast |
| Mechanisms | Low pressure over north-west India in summer; shift of the ITCZ; easterly jet stream; El Niño weakens and La Niña strengthens the monsoon |
| Withdrawal | The subtropical westerly jet stream returning south of the Himalayas helps the monsoon withdraw |
| Highest rainfall | Mawsynram and Cherrapunji (Meghalaya) |
| Mango showers | Pre-monsoon showers in Kerala and Karnataka |
| Kalbaisakhi | Evening thunderstorms in Bengal (Nor'westers) |
2. Soils of India
| Soil | Found in | Notes |
|---|---|---|
| Alluvial | Northern plains, river deltas | Most widespread; fertile |
| Black (regur) | Deccan: Maharashtra, Gujarat, MP | From basalt; holds moisture; best for cotton |
| Red and yellow | Eastern and southern peninsula | Red from iron oxide |
| Laterite | High-rainfall areas: Kerala, Karnataka, Odisha hills | Good for cashew, tea |
| Arid (desert) | Rajasthan | Sandy, saline |
| Mountain (forest) | Himalayan slopes |
3. Natural Vegetation
| Forest type | Rainfall | Examples |
|---|---|---|
| Tropical evergreen | Over 200 cm | Western Ghats, North-east; ebony, mahogany, rosewood |
| Tropical deciduous (monsoon) | 70-200 cm | Most widespread; teak, sal |
| Thorn and scrub | Under 70 cm | Rajasthan; acacia, babool, kikar |
| Mangrove (tidal) | Deltas | Sundarbans (sundari tree) |
| Montane | Hills | Deodar, pine, oak |
✗ Black soil is best for tea | ✓ Black soil suits cotton; tea grows on well-drained hill and laterite soils
✗ The north-east monsoon brings rain to Kerala | ✓ It mainly brings rain to the Tamil Nadu coast
हिंदी नोट: दक्षिण-पश्चिम मानसून जून से सितंबर तक; अरब सागर और बंगाल की खाड़ी शाखाएँ। काली (रेगुर) मिट्टी कपास के लिए सबसे अच्छी है; जलोढ़ मिट्टी सबसे अधिक क्षेत्र में; मरुस्थलीय मिट्टी मुख्यतः राजस्थान में। उष्णकटिबंधीय पर्णपाती (मानसूनी) वन भारत में सबसे अधिक फैले हैं।
Exam Pointer: Verified NTPC patterns: the state where desert soil is mostly found (June 2025 Graduate CBT-1) and the role of the subtropical jet stream in monsoon withdrawal (June 2025 Graduate CBT-1). Forest-type questions are tagged syllabus-based.
Pariksha Pattern: Every Way NTPC Asks This Topic
Pattern 1: Soils and where they are found
[PYQ: NTPC Graduate CBT-1 18-Jun-2025 Shift-1]
EXAM LEVEL
Q. In which state is desert soil mostly found?
Rajasthan.
Answer: Rajasthan
EXAMATLAS LEVEL
Q. Which soil is best for cotton and what is it formed from, and which is the most widespread soil in India?
Black (regur) soil, formed from basalt (Deccan lava). Alluvial soil is the most widespread.
Answer: Black soil, from basalt; alluvial
Pattern 2: Monsoon mechanism
[PYQ: NTPC Graduate CBT-1 12-Jun-2025 Shift-3]
EXAM LEVEL
Q. Which two branches does the south-west monsoon have?
The Arabian Sea branch and the Bay of Bengal branch.
Answer: Arabian Sea and Bay of Bengal branches
EXAMATLAS LEVEL
Q. How does the subtropical westerly jet stream affect the monsoon, and which ocean event weakens the Indian monsoon?
Its return south of the Himalayas helps the monsoon withdraw. El Niño weakens the monsoon.
Answer: It helps withdrawal; El Niño
Pattern 3: Seasonal rain names and records
[Pattern: syllabus-based, PYQ-style]
EXAM LEVEL
Q. Which place in Meghalaya receives the highest rainfall?
Mawsynram.
Answer: Mawsynram
EXAMATLAS LEVEL
Q. What are pre-monsoon showers in Kerala called, and which region gets most of its rain from the north-east monsoon?
Mango showers; the Tamil Nadu coast.
Answer: Mango showers; Tamil Nadu coast
Pattern 4: Forest types
[Pattern: syllabus-based, PYQ-style]
EXAM LEVEL
Q. Which is the most widespread forest type in India?
Tropical deciduous (monsoon) forest.
Answer: Tropical deciduous
EXAMATLAS LEVEL
Q. Which forests grow where rainfall exceeds 200 cm, and which tree gives the Sundarbans its name?
Tropical evergreen forests; the sundari tree.
Answer: Tropical evergreen; sundari
60-Second Revision
- SW monsoon June-Sept (two branches); NE monsoon wets Tamil Nadu.
- El Niño weakens, La Niña strengthens; jet stream aids withdrawal.
- Black soil cotton (Deccan); desert soil Rajasthan; alluvial most widespread.
- Deciduous forests most widespread; evergreen over 200 cm; mangroves in the Sundarbans.