India: Climate, Soils and Natural Vegetation
India’s climate, soils and natural vegetation are closely linked. The exam tests monsoon mechanisms, soil properties and vegetation–rainfall relationships.
Core rules
- The monsoon is a seasonal reversal: summer heating shifts the ITCZ, the Somali jet strengthens moisture flow, and the tropical easterly jet supports upper-level outflow.
- Seasons: cold weather, hot weather, south-west monsoon and retreating monsoon.
- Major soils: alluvial (fertile, transported), black or regur (clayey, moisture-retentive, from basalt), red (weathered crystalline rock), laterite (leached, acidic), desert and mountain soils.
- Vegetation types: tropical evergreen, tropical deciduous, thorn, montane and mangrove.
- Rainfall variability makes irrigation, drought planning and flood control necessary.
Worked example
Why is black soil suited to cotton? It forms from weathered basalt, is rich in clay and retains moisture, so cotton can survive dry spells. It is also dark and warms quickly. The reasoning connects parent rock, texture, moisture regime and crop choice. Laterite, by contrast, is leached and acidic, so it suits cashew, tea or rubber with management rather than cotton.
Traps
Do not call black soil black alluvium; it is volcanic in origin. Do not say laterite is naturally fertile. Do not equate tropical deciduous forest with evergreen forest. Do not explain the monsoon only by differential heating; pressure, jets and relief also matter.