Land Degradation

Land degradation is the temporary or permanent decline in the productive capacity of land due to a combination of natural geomorphic processes and anthropogenic pressures. Under the Soils and Land Resources unit of Indian Geography, land degradation is analyzed as a critical environmental and economic challenge, as it directly compromises food security, alters hydrological cycles, and accelerates desertification.

Distinction Between Land Degradation and Desertification

• Land Degradation: A global phenomenon occurring across all climatic zones, involving the decline in soil quality, vegetation cover, or water resources.
• Desertification: A specific subset of land degradation occurring exclusively in arid, semi-arid, and dry sub-humid areas (collectively known as drylands), resulting from climatic variations and human activities.

Institutional Monitoring and Data Framework

The Space Applications Centre (SAC) of the Indian Space Research Organisation (ISRO), in collaboration with partner institutions, periodically publishes the Desertification and Land Degradation Atlas of India. This baseline assessment utilizes high-resolution satellite remote sensing data to map and monitor the spatial distribution of degraded tracts across the country.

Major Drivers and Mechanisms of Land Degradation in India

Land degradation in India is driven by a complex interplay of physical vulnerabilities and unsustainable resource management.

Water Erosion

Water erosion remains the single largest contributor to land degradation in India, accounting for over half of the total degraded area. It manifests as sheet, rill, and gully erosion, removing nutrient-rich topsoil from steep Himalayan slopes, the Western Ghats, and the rolling terrains of the Peninsular Plateau.

Vegetation Degradation

Vegetation degradation involves the reduction in density, canopy cover, or biomass volume of natural forests and grasslands. This is primarily caused by deforestation, overexploitation of timber, forest fires, and the grazing of livestock far beyond the carrying capacity of pastures.

Wind Erosion

Wind erosion is highly active in the hyper-arid and arid tracts of western India. Strong summer winds dislodge and transport loose, dry sandy particles, causing topsoil removal, shifting sand dunes, and the encroachment of sand sheets onto surrounding fertile fields.

Salinization and Alkalinization

Salinization is the accumulation of free soluble salts on the soil surface, while alkalinization involves the high saturation of exchangeable sodium ions. This type of degradation is largely an anthropogenic byproduct of over-irrigation in canal-command areas, where capillary action lifts subsoil salts to the surface crust.

Acidification and Nutrient Depletion

Soil acidification occurs when intense rainfall leaches away soluble bases like calcium and magnesium, leaving behind toxic concentrations of iron and aluminum. Nutrient depletion refers to the chronic loss of Soil Organic Carbon (SOC) and primary macronutrients due to intensive cultivation without adequate organic recycling.

Geographical Distribution and State-Wise Hotspots

The intensity and dominant process of land degradation vary significantly across India’s distinct physiographic zones.

Structural Matrix of Land Degradation Processes in India

The following framework delineates the specific spatial footprint and underlying causes of the primary degradation processes monitored by national agencies.

1. Fluvial Degraded Lands

• Causative Agents: Torrential rainfall, rapid surface runoff, and loss of riparian vegetation.
• Spatial Distribution: Sub-Himalayan Tarai region, Western Ghats foothills, and major river basins like the Chambal, Yamuna, and Mahanadi.
• Impact: Loss of root-anchoring capacity, rapid removal of humic topsoil, and severe downstream reservoir siltation.

2. Eolian Degraded Lands

• Causative Agents: High-velocity summer winds, high aridity indices, and complete absence of shelterbelts.
• Spatial Distribution: Thar Desert core (Jaisalmer, Barmer, Bikaner) and transitional districts of Haryana and Southwest Punjab.
• Impact: Destruction of agricultural crops via abrasive sandblasting and burial of communication and transport infrastructure.

3. Chemical Degraded Lands (Salt-Affected)

• Causative Agents: Shallow water tables, seepage from unlined canals, and heavy application of chemical fertilizers.
• Spatial Distribution: Indogangetic alluvial plains, coastal pockets, and the black soil zones of the Deccan under canal command.
• Impact: Development of barren white crusts (Reh or Usar), loss of soil osmotic potential, and standard crop failure.

4. Biological Degraded Lands

• Causative Agents: Chronic depletion of soil organic matter, lack of green manuring, and destruction of soil macrofauna.
• Spatial Distribution: Pan-India, particularly intensive rainfed agricultural tracts.
• Impact: Drop in soil microbial respiration, compaction of soil structure, and low nutrient-use efficiency.

National Policies and Institutional Strategies for Reclamation

India employs a combination of engineering, biological, and legislative tools to arrest land degradation and restore ecological stability.

Sustainable Land Management Interventions

• Mechanical Reclamation: Constructing engineering structures such as contour bunds, graded trenches, bench terraces, and gabion check dams to reduce the slope length and velocity of runoff.
• Chemical Remediation: Applying gypsum (calcium sulfate) or agricultural pyrites to exchange harmful sodium ions with calcium ions, followed by deep leaching to reclaim alkaline soils.
• Biological Engineering: Planting deep-rooted, site-specific vegetative barriers like Vetiver grass (Chrysopogon zizanioides) to lock topsoil, and deploying multi-row shelterbelts to act as windbreaks.

Key Government Schemes and Institutional Initiatives

• Pradhan Mantri Krishi Sinchayee Yojana (PMKSY-WDC): Focuses on the holistic development of degraded watersheds using geospatial resource mapping, rainwater harvesting, and community-based land treatment.
• Soil Health Card Scheme: A diagnostic tool assessing 12 soil parameters to prevent the over-application of specific fertilizers, thereby curbing secondary chemical land degradation.
• National Mission for a Green India (GIM): One of the eight missions under the National Action Plan on Climate Change (NAPCC), aimed at improving forest canopy cover and restoring degraded ecosystems.
• Paramparagat Krishi Vikas Yojana (PKVY): Promotes organic farming, agroforestry, and low-input sustainable agriculture to restore soil organic carbon pools.

UPSC Prelims Facts and Trivia

United Nations Convention to Combat Desertification (UNCCD)

The UNCCD is the sole legally binding international agreement linking environment and development to sustainable land management. India is a signatory to the convention, and the Ministry of Environment, Forest and Climate Change (MoEFCC) acts as the national focal point for its implementation.

Land Degradation Neutrality (LDN)

LDN is a state whereby the amount and quality of land resources necessary to support ecosystem functions and enhance food security remain stable or increase within specified temporal and spatial scales. India has committed to achieving LDN targets by restoring 26 million hectares of degraded land by 2030, in line with Sustainable Development Goal (SDG) Target 15.3.

The “Three Rio Conventions”

The trio of international treaties adopted at the 1992 Earth Summit in Rio de Janeiro includes the UNCCD, the United Nations Framework Convention on Climate Change (UNFCCC), and the Convention on Biological Diversity (CBD). Land degradation directly intersects all three, as it impacts carbon sequestration, biodiversity conservation, and sustainable livelihoods.

Central Soil Salinity Research Institute (CSSRI)

Located in Karnal, Haryana, this premier research body under the Indian Council of Agricultural Research (ICAR) is dedicated to developing isolation and management protocols for salt-affected and waterlogged soils across India.