Soil Erosion

Types, Causes, Effects, Conservation Methods

Edu Level: Unit2

Date: Aug 11 2025 - 4:48 PM

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The removal of topsoil by wind and water, leading to loss of soil fertility and eventual land degradation.

Deforestation / Removal of Vegetation – Roots bind soil; leaf litter reduces raindrop impact. Removal exposes soil to rain-splash, runoff, wind.
Squatting on Hillsides – Clearing land for homes and crops increases slope exposure to erosion.
Ploughing Up & Down Slopes – Creates gullies that channel water downslope, removing soil.
Unsustainable Agriculture – Overgrazing, bare fields after harvest, forest clearance for ranching; leaves topsoil unprotected.
Quarrying – Strips vegetation, excavates land → major soil loss and degradation.
Urbanisation – Increases impermeable surfaces and rapid runoff, washing away exposed soil.
Landslides – Natural movement of regolith and topsoil downslope.

Loss of Fertile Land – Reduces agricultural productivity; worsens food security as population grows.
Desertification – Vegetation loss leads to arid conditions; worsened by climate change (droughts, reduced rainfall) and poor land use. Example: Haiti – ~50% of land degraded due to deforestation and poor farming.
Water Pollution – Sediment from erosion contaminates rivers.
Damage to Coral Reefs – Sediment blocks sunlight, kills coral polyps.
Health Hazards – Sediment blocks watercourses, creating stagnant pools → breeding grounds for disease vectors like mosquitoes.

Agronomic Methods

No-Till Planting – Keeps previous plant roots intact to hold soil.
Strip Cropping – Alternating crop strips; often combined with crop rotation for continuous cover.
Contour Ploughing – Ploughing across slopes to prevent gully erosion.
Agroforestry – Integrating trees/shrubs with crops for wind protection, microclimate regulation, water retention.
Mulching – Organic cover reduces raindrop impact, improves moisture retention and soil structure.
Windbreaks – Trees planted between fields to reduce wind erosion.
International Action –
- 1994 UN Convention to Combat Desertification.
- Haiti case – FAO restored 11,645 ha by planting 5M seedlings.

Mechanical / Engineering Methods

Terracing – Step-like platforms on slopes reduce gradient and runoff (e.g. Lady Young Road, Trinidad).
Gabion Baskets – Wire cages filled with rocks to support slopes, slow runoff, trap sediment.
Check Dams – Small barriers in gullies to slow water, trap sediment, recharge groundwater.
Stormwater Diversion Drains – Channels to redirect runoff from upslope to safe/useful areas.