Land Resources and Land-Use Change Study Notes

2.7 LAND RESOURCES AND LAND-USE CHANGE

2.7.1 LAND AS A RESOURCE

• Land is a finite and valuable resource, providing essential materials such as:

  • Food

  • Fibre

  • Medicines

  • Fuel

  • Wood

• Classified as a natural resource, land can be considered renewable if utilized properly.

• Essential for the survival of humans and other terrestrial life forms, supporting biodiversity.

• Used for various purposes including:

  • Habitation

  • Industrial activities

  • Shopping complexes

  • Transportation

• Plays a significant role in economic, social, and cultural development.

2.7.1.1 Maintenance of Land Resources

• Given its finite nature, land must be maintained to ensure fertility and sustained yield.

• Topsoil is classified as a renewable resource because it is continually regenerated, albeit at a slow rate of formation, taking about 200-1000 years to form one inch (2.5cm) of topsoil, depending on climate and soil type.

• If erosion rates exceed renewal rates, topsoil becomes a non-renewable resource.

2.7.1.2 Land Use Planning

• Land use planning is necessary for regulating land use and promoting efficient resource utilization at:

  • Individual level

  • Societal level

  • National level

• For example, in India, land is categorized into features such as:

  • Plains (43%)

  • Mountains (30%)

  • Plateaus (27%)

• Different land-use categories include:

  1. Forests

  2. Non-agricultural uses (urban settlements, infrastructure, commercial, and industrial).

  3. Permanent pastures and grazing lands.

  4. Barren and wastelands.

  5. Miscellaneous trees, crops, and groves.

  6. Culturable wasteland.

  7. Fallow land.

  8. Net area sown including crop sown area.

2.7.1.3 Land-Use Change

• To mitigate land-use conflicts, plans are implemented based on regulations like zoning.

• Population growth leads to land-use changes such as:

  • Deforestation

  • Urban sprawl

  • Desertification

• Land-use change refers to converting land from its traditional use to other purposes, often involving:

  • Natural ecosystems (e.g. forests into agricultural land)

  • Developmental activities (e.g. industry, housing).

• The necessity for land-use change is often for economic or social development, yet this transformation incurs environmental costs, including:

  • Increased greenhouse gases contributing to climate change

  • Pollution from intensive agricultural practices

  • Endangerment of species via wetland conversion

  • Polluted air, water, and soil due to industrial conversion.

• In summary, land conversion has drastic impacts on ecosystem processes and services, potentially undermining economic and social progress.

2.8 LAND DEGRADATION

• The growing population increases demand for arable land leading to degradation due to over-exploitation.

• Soil degradation is alarming as soil formation is extremely slow.

• Average annual erosion rates are 20-100 times greater than soil formation rates, leading to:

  • Soil erosion

  • Water-logging

  • Salinization

  • Soil contamination by industrial wastes like heavy metals or fly ash.

2.8.1 SOIL EROSION

• Defined as the removal and movement of soil components, particularly the topsoil, from one location to another.

• Results in loss of soil fertility because the fertile topsoil layer is eroded.

• Approximately one-third of the world's cropland is experiencing erosion, predominantly in Asia and Africa, where two-thirds of seriously degraded lands are located.

• Types of soil erosion:

  1. Normal erosion (Geologic erosion): Gradual removal of topsoil through natural processes maintaining equilibrium.

  2. Accelerated erosion: Caused by human activities (overgrazing, deforestation, mining), leading to rapid erosion compared to soil formation.

2.8.1.1 Agents of Soil Erosion

• Climatic Agents:

  • Water:

  • Various forms including torrential rains and snowmelt.

  • Types of water-induced soil erosion:

    • Sheet erosion: Uniform removal of a thin layer over large areas.

    • Rill erosion: Finger-shaped grooves form from rainfall.

    • Gully erosion: Deeper U or V-shaped gullies form from heavy rainfall.

    • Slip erosion: Occurs on steep slopes during heavy rainfall.

    • Stream bank erosion: Resulting from rapidly flowing streams cutting into banks.

  • Wind:

  • Types of wind erosion:

    • Saltation: Soil particles (1-1.5mm) move upward under wind's direct pressure.

    • Suspension: Fine particles (<1mm) remain airborne.

    • Surface creep: Larger soil particles (5-10mm) creep along the surface.

• Biotic Agents: Human activities such as overgrazing, mining, and deforestation lead to erosion by removing vegetation preventing soil exposure to erosion forces.

2.8.1.2 Prevention of Soil Erosion

• Conservation practices include:

  1. Conservational till farming: Minimizes soil disturbance compared to traditional methods.

  2. Contour farming: Cultivation across slopes helps slow runoff and retain soil.

  3. Terracing: Converts steep slopes into broad terraces to retain water.

  4. Strip cropping: Alternates strips of crops with soil-saving cover crops to reduce runoff.

  5. Alley cropping: Plants crops between rows of trees or shrubs to retain soil.

  6. Wind breaks: Planting rows of trees to block wind and reduce erosion.

2.8.2 WATER LOGGING

• Caused by excessive irrigation leading to underground water accumulation affecting crop growth.

• Waterlogged soils inhibit gas exchange in roots, deteriorating crop health.

• Often associated with salinity due to irrigation water containing salts.

• Affected areas and salinity showed significant economic losses estimated at 10,000 million per annum in India.

2.8.3 LANDSLIDES

• Caused by human activities such as:

  • Hydroelectric projects

  • Road and railway construction

  • Mining

• Increased frequency of landslides following major construction activities, exacerbating erosion and soil displacement.

2.8.4 DESERTIFICATION

• Defined as a significant reduction in productivity (≥10%).

• Describes conversion of arid/semi-arid land regions into desert-like conditions, marked by:

  • Devegetation and loss of plant cover

  • Water depletion and salinization

  • Soil erosion

• Desertification causes a severe loss in agricultural productivity, characterized in regions across the globe.

Causes of Desertification

• Natural Phenomena: Climate change affecting vegetation and soil moisture levels.

• Human Activities:

  1. Deforestation: Eliminating tree cover exacerbates runoff, erosion, and soil fertility reduction.

  2. Overgrazing: High cattle populations contribute significantly to land denudation.

  3. Mining and Quarrying: Create vast bare areas leading to erosion and land degradation.

2.9 ROLE OF INDIVIDUAL IN CONSERVATION OF NATURAL RESOURCES

• Emphasizes individual responsibility for protecting and conserving resources, including:

  • Forests

  • Water

  • Soil

  • Energy

• Strategies for conservation include:

  • Water conservation techniques:

  • Avoid running taps unnecessarily.

  • Repair leaks promptly to prevent waste.

  • Use rainwater harvesting systems.

  • Energy conservation strategies:

  • Turn off unused appliances, harness natural heat for drying.

  • Utilize solar energy where possible.

  • Soil protection:

  • Avoid uprooting trees during construction.

  • Promote composting and use of organic fertilizers.

  • Implement mixed cropping to maintain soil health.

• Overall, individual actions contribute significantly to broader conservation efforts.

2.10 EQUITABLE USE OF RESOURCES FOR SUSTAINABLE LIFESTYLE

• The importance of equitable resource distribution to prevent displacement of local communities and to ensure sustainable development for all.

• Acknowledges disparities caused by development efforts requiring attention to the needs and rights of marginalized populations.