BharatNotes What is Soil Erosion and Conservation?
Soil erosion is the removal of the nutrient-rich topsoil by natural agents — chiefly running water and wind — at a rate faster than soil formation. Because topsoil forms over centuries, erosion is effectively an irreversible loss within human timescales. Soil conservation is the deliberate management of land to prevent erosion and sustain fertility, combining agronomic, mechanical (engineering) and biological measures. The two are studied together because conservation is the corrective response to erosion's drivers: deforestation, faulty farming, overgrazing and intense rainfall on bare, sloping land.
Types of Soil Erosion
Water erosion in India progresses through a recognised sequence:
| Type | Description |
|---|---|
| Splash erosion | Raindrop impact detaches individual soil particles — the first stage |
| Sheet erosion | Thin, uniform removal of topsoil over a wide area by surface runoff |
| Rill erosion | Finger-like channels appear on cultivated land after sheet erosion |
| Gully erosion | Enlarged rills cut deep channels; advances by headward erosion |
Wind erosion dominates in arid and semi-arid regions (e.g. western Rajasthan), removing fine particles through suspension and saltation. The Chambal ravines (Madhya Pradesh–Rajasthan–Uttar Pradesh) are India's classic example of severe gully erosion, with some gullies exceeding 80 metres in depth.
Current Status in India
The scale is large. A widely cited estimate (Narayana and Ram Babu, 1983) puts the average erosion rate at about 16.35 tonnes per hectare per year, totalling roughly 5,334 million tonnes annually for the country.
On degradation, ISRO's Desertification and Land Degradation Atlas of India (Space Applications Centre, published June 2021) reported that about 97.85 million hectares (29.7% of total geographical area) underwent land degradation in 2018–19, up from 94.53 mha (2003–05) and 96.40 mha (2011–13). Desertification affected about 83.69 mha in 2018–19. Degradation rose in 28 of 31 states/UTs between 2011–13 and 2018–19, with Rajasthan, Maharashtra and Gujarat among the largest contributors.
Conservation Methods and Government Initiatives
Mechanical: contour bunding (earthen bunds along contour lines to slow runoff), terracing on hill slopes, check dams, nala bunds and percolation tanks. Agronomic/biological: contour ploughing, crop rotation, strip cropping, mulching, cover crops, and afforestation/reforestation of degraded and ravine land.
Key programmes (verified):
- Watershed Development Component of PMKSY (WDC-PMKSY 2.0) — approved 15 December 2021 for 2021–26, with an indicative central outlay of about Rs 8,134 crore and a physical target near 49.50 lakh hectares, using a ridge-to-valley approach.
- MGNREGA, which funds afforestation and soil-and-water conservation works.
- National Mission for Sustainable Agriculture (NMSA) and the Soil Health Card scheme.
UPSC Angle
Treat this as a high-yield linkage topic: connect erosion types and soil regions (GS1) to land degradation neutrality, watershed development and desertification (GS3). Remember the water-erosion sequence, the Chambal ravines as the gully-erosion exemplar, and contour bunding versus terracing as distinct mechanical measures — a frequent point of confusion.
