A reddish, iron and aluminium rich soil formed by intense leaching in regions of high temperature and heavy seasonal rainfall, typically infertile but hardening into a useful building material.
- Forms under hot, humid climates with alternating wet and dry seasons, where heavy rain leaches away silica and bases, leaving behind iron and aluminium oxides (hence the red colour).
- Low in fertility, low in nitrogen, lime, and humus; acidic and prone to erosion, but responds to manuring and fertiliser.
- Found on the summits of the Western Ghats, the Eastern Ghats, parts of Karnataka, Kerala, Tamil Nadu, Madhya Pradesh, Odisha, and the Assam hills.
- When dried and cut into blocks it hardens irreversibly, so it has long been used as a building brick (the name comes from the Latin "later", meaning brick).
- Suited to plantation crops such as tea, coffee, rubber, cashew, and coconut with proper inputs.
The leaching origin, the iron-aluminium (red) composition, the use as building brick, the hill-top occurrence, and the plantation-crop suitability are recurring soils facts.
Laterite soil is leached and infertile (good for plantation crops with inputs and for brick-making), unlike the river-deposited, highly fertile alluvial soil. Both can look reddish, but the cause and fertility differ.
Leached, iron-aluminium-rich red soil of hot wet uplands; infertile but hardens into brick; suits plantation crops.