GS Notes

1.5 - Geography Notes 41

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Elaborate Notes

SOILS OF INDIA

Soil is the thin upper layer of the Earth’s crust, composed of a mixture of rock particles and organic matter, which supports plant life. The study of soils is known as Pedology. In India, the classification of soils has been attempted by various agencies, most notably the Indian Council of Agricultural Research (ICAR), which builds upon earlier work like that of the Soil Survey of India established in 1956.

  • Common Characteristics of Indian Soils

    • Nitrogen Deficiency: A pan-India characteristic is the general deficiency of nitrogen in soils. This is primarily attributed to high temperatures that lead to rapid decomposition of organic matter by soil microbes, and traditional agricultural practices that often do not adequately replenish nitrogen. This necessitates the extensive use of nitrogenous fertilizers like urea.
    • Iron Content: Laterite and Red soils, predominantly found in the peninsular region, are rich in iron oxides. The reddish or yellowish colour of these soils is due to the presence of ferric oxides (rust). In Laterite soils, this is a result of intense leaching, which removes silica and leaves behind concentrations of iron and aluminium oxides.
    • Humus Content: Humus, the stable, dark-coloured organic matter, is crucial for soil fertility and structure. Its presence varies significantly:
      • Rich: Black soils (Regur) of the Deccan plateau have a good humus content due to their fine texture and high moisture retention. Mountain & Forest soils are rich in humus due to the accumulation of leaf litter and slow decomposition rates under cool, moist conditions. Peaty soils, formed in waterlogged areas, have extremely high organic matter content due to anaerobic conditions that inhibit decomposition.
      • Poor: Alluvial, Red, and Laterite soils are generally deficient in humus.
    • Salt Content: Arid soils, found in Western Rajasthan and parts of Gujarat, are characterized by high salt content. This is due to high rates of evaporation exceeding precipitation, which draws mineral salts from lower soil profiles to the surface through capillary action, a process known as salinization.
    • Black Soil Colour: The distinctive black colour of these soils is attributed to the presence of a fine-grained clay-humus complex and compounds like titaniferous magnetite, derived from the weathering of the basaltic parent rock of the Deccan Traps.

  • RED SOIL

    • Formation: Formed under conditions of moderate precipitation and moderate to high temperatures, allowing for chemical weathering of crystalline and metamorphic rocks like granite and gneiss of the Archaean period. The red colour is due to the wide diffusion of ferric oxide. It appears yellow when in a hydrated form.
    • Properties: These soils are typically loamy to sandy loam, well-drained but have low water retention capacity. They are rich in iron, magnesium, and aluminium but are characteristically poor in nitrogen, phosphorus, and humus. They are generally not fertile but can be made productive with the application of fertilizers and irrigation.
    • Regions: They cover a vast area of peninsular India, including Tamil Nadu, parts of Karnataka, southern Andhra Pradesh, eastern Madhya Pradesh, Chhattisgarh, Odisha, and the Chota Nagpur plateau. They are also found in parts of the North-East.

  • LATERITE SOIL

    • Formation: The term ‘Laterite’ is derived from the Latin word ‘later’ meaning brick. As described by Francis Buchanan-Hamilton (1807), these soils are formed under conditions of high temperature and high seasonal precipitation, typical of monsoon climates. These conditions lead to intense leaching, a process called laterization, where silica and other soluble bases are washed away, leaving a residue rich in iron and aluminium oxides (sesquioxides).
    • Properties: They are acidic in nature due to the leaching of alkaline components. They are poor in silica, bases (like calcium and magnesium), humus, nitrogen, and phosphate. They are, however, rich in iron and aluminium oxides. When dried, they become very hard, making them suitable for use as building bricks.
    • Utility: While generally infertile for food crops, they are well-suited for plantation crops like tea, coffee, rubber, cashew nuts, and spices with proper manuring and irrigation.
    • Regions: Found in patches on the summits of hills and plateaus, such as the Western Ghats (on its western side), parts of Odisha, the Meghalaya plateau (Shillong plateau), and the southern parts of the Aravalli range.

  • BLACK SOIL

    • Formation: Also known as Regur Soil or Black Cotton Soil, these are in-situ soils formed from the weathering of basaltic lava flows of the Deccan Trap, which erupted during the Cretaceous period.
    • Properties: The colour is due to titaniferous magnetite and humus content. They are clayey in texture, highly retentive of moisture, and rich in lime, iron, magnesium, and alumina. They are deficient in nitrogen and phosphorus. A unique characteristic is self-ploughing; they swell and become sticky when wet, and develop deep cracks upon drying, which aids in soil aeration.
    • Regions: These soils dominate the Deccan Plateau, including most of Maharashtra, western Madhya Pradesh, southern Gujarat, northern Karnataka, and parts of Telangana and Andhra Pradesh.

  • ALLUVIAL SOIL

    • Formation: These are transported or ex-situ soils, formed by the deposition of sediments (alluvium) carried by rivers. They are geologically young and represent the most widespread soil type in India.
    • Properties: Their chemical composition varies depending on the source of the sediment. They are generally rich in potash and lime but deficient in nitrogen and humus. They lack well-developed soil profiles or marked differences in layers (horizons) due to their recent depositional nature. They are classified based on age into older alluvium (Bhangar) and newer alluvium (Khadar).
    • Regions: They cover the vast Northern Plains (Indo-Gangetic-Brahmaputra plains) and the coastal plains (Mahanadi, Godavari, Krishna, and Kaveri deltas).

  • ARID & DESERT SOIL

    • Formation: Found in arid and semi-arid regions characterized by high temperatures and low rainfall. High evaporation rates lead to the accumulation of salts on the surface.
    • Properties: They are sandy to gravelly in texture, with low moisture content. They are saline and alkaline in nature, often containing a high percentage of soluble salts. They are deficient in nitrogen and humus. With proper irrigation, as seen in the Indira Gandhi Canal command area, these soils can be made productive.
    • Regions: Predominantly found in Western Rajasthan, Northern Gujarat, and southern parts of Haryana and Punjab.

  • MOUNTAIN & FOREST SOIL

    • Formation: Found in hilly and mountainous regions with sufficient rainfall. The character of these soils changes with parent rock, ground configuration, and climate.
    • Properties: In valleys, they are loamy and silty, but on upper slopes, they are coarse-grained and thin-layered (immature). Forest soils are typically rich in organic content (humus). However, due to slow decomposition under cooler temperatures, the humus is not well-integrated, leading to an acidic nature.
    • Regions: Found along the Himalayan ranges, parts of the Vindhyas and Satpuras, and forested areas of the Western and Eastern Ghats.

  • PEATY SOIL

    • Formation: These soils develop in areas of heavy rainfall and high humidity, leading to waterlogged or submerged conditions. This promotes a large accumulation of organic matter.
    • Properties: They are characterized by a very high content of organic matter and humus, often exceeding 40-50%. They are heavy, dark-coloured, and highly acidic. When properly drained and utilized, they are used for rice cultivation.
    • Regions: Found in the deltas of major rivers (e.g., Sundarbans), estuaries, the Kottayam and Alappuzha districts of Kerala (known as Kari soils), and parts of coastal Odisha.

WATER RESOURCES

  • Oceanic Resources A resource is any natural or man-made substance that has utility or economic value. Oceanic resources are vital components of the “Blue Economy”.

    • Types of Oceanic Resources

      • 1) Mineral Resources:

        • Dissolved Form: Seawater contains numerous dissolved minerals. Common salt (sodium chloride) is the most abundant. Other commercially extracted salts include those of magnesium, bromine, and potassium.
        • Deposited Form: These are solid minerals found on the seabed.
          • Continental Shelf: This shallow, submerged extension of the continent is a source of:
            • Minor minerals: Sand, gravel, and silt used for construction.
            • Placer deposits: Heavy minerals concentrated by wave and current action, such as Magnetite (iron ore), Gold placers (e.g., off the coast of Alaska), and Monazite sand. The Kerala coast and India’s entire eastern coast are rich in Monazite, a key source of Thorium and Rare Earth Elements (REEs), which are critical for high-end technology manufacturing (e.g., electronics, magnets, catalysts).
            • Biotic resources: Corals and pearls.
          • Deep Ocean:
            • Polymetallic Nodules (PMN) or Manganese Nodules: Potato-sized accretions of minerals found on the abyssal plains at depths of 4,000-6,000 meters. They are rich in manganese, nickel, copper, and cobalt. The Central Indian Ocean Basin (CIOB) is a significant area for PMN, where India has exclusive exploration rights granted by the International Seabed Authority (ISA).
            • Polymetallic Sulphides: Found near hydrothermal vents (underwater geysers) along mid-oceanic ridges. As superheated, mineral-rich water from the Earth’s crust mixes with cold seawater, it deposits sulphides of metals like copper, zinc, lead, gold, and silver.

      • 2) Energy Resources:

        • Petroleum and Natural Gas: Formed from the remains of marine organisms trapped in sedimentary rocks. Major offshore reserves are found on continental shelves. The North Sea (producing Brent crude), Persian Gulf, and Caspian Sea are prime examples. In India, the Mumbai High field is a significant offshore oil and gas producer.
        • Coal: While less common, underwater coal seams exist in some parts of the world.
        • Tidal Energy: Harnesses the energy from the rise and fall of tides. Requires a large tidal range. The Gulf of Khambhat and Gulf of Kutch on the Gujarat coast have the highest potential in India.
        • Wave Energy: Utilizes the kinetic energy of the up-and-down motion of ocean waves to generate electricity.
        • Ocean Thermal Energy Conversion (OTEC): Works on the principle of the temperature difference between warm surface water and cold deep ocean water to run a heat engine. A temperature difference of at least 20°C is required.
        • Wind and Solar Energy: Offshore wind farms and floating solar panels are increasingly being deployed to harness these renewable resources over the ocean surface.
        • Nuclear Energy Sources: Thorium from monazite sands can be used as fuel in advanced nuclear reactors. Seawater also contains deuterium, which can be extracted to produce Heavy Water (D₂O), used as a moderator and coolant in nuclear reactors.
        • Green Hydrogen: Can be produced by electrolysis of seawater using renewable energy (like offshore wind or solar).

      • 3) Food Resources:

        • Fish and Seafood: Includes finfish, crustaceans (prawns, lobsters, crabs), and molluscs (oysters, mussels). Fisheries are a critical source of protein and livelihood for millions.
        • Seaweeds: Marine algae that are a source of food, animal feed, and raw materials for industries (e.g., alginates, agar). With climate change impacting terrestrial agriculture, seaweeds (aquaculture) are seen as a major alternative food source.

      • 4) Water Resource:

        • Desalination: The process of removing salts from seawater to produce freshwater. Major methods include Reverse Osmosis (RO) and Electrodialysis. India’s National Institute of Ocean Technology (NIOT) has developed an indigenous Low-Temperature Thermal Desalination (LTTD) technology, which utilizes the ocean’s thermal gradient and is suitable for island territories like Lakshadweep.

ISSUES IN EXTRACTION OF OCEANIC RESOURCES

  • Technological Hurdles:

    • OTEC: The technology is still in a nascent stage and not yet commercially viable on a large scale due to low thermal efficiency.
    • Polymetallic Nodules (PMN): Deep-sea mining at depths of 4-6 km presents immense technological challenges, from extraction systems to vertical transport and processing. India’s Samudrayaan Mission aims to develop the technology for this.
    • Desalination: While technologies like RO exist, they are energy-intensive. The brine discharge (highly concentrated salt water) can harm local marine ecosystems. LTTD is promising but has geographical limitations.
    • Thorium: India has vast thorium reserves, but the technology to utilize it commercially in the third stage of its nuclear program is still under development.

  • Cost:

    • The high capital investment required for deep-sea mining, OTEC plants, and large-scale desalination makes these ventures economically challenging, especially compared to terrestrial alternatives.

  • Distribution and Geopolitics:

    • Uneven Distribution: Key resources like PMNs are concentrated in specific regions (e.g., Clarion-Clipperton Zone in the Pacific, Central Indian Ocean Basin, Peru Basin). Similarly, petroleum reserves are clustered in regions like the Persian Gulf.
    • Governance Deficit: This concentration raises governance issues, managed by bodies like the International Seabed Authority (ISA) under the UN Convention on the Law of the Sea (UNCLOS). Debates persist on benefit-sharing between technologically advanced nations and the global community.
    • Resource Curse and Dutch Disease: Nations heavily dependent on a single resource (e.g., Venezuela on oil) can suffer from economic instability, corruption, and neglect of other sectors.
    • Conflict: Competition over resources can lead to regional tensions and conflicts over maritime boundaries.

  • Physical Barriers:

    • The deep ocean environment is hostile: extreme pressure, complete darkness, and near-freezing temperatures require specialized, robust, and expensive equipment (e.g., Remotely Operated Vehicles - ROVs). Geological features like mid-oceanic ridges and volcanic activity pose additional risks.

  • Environmental/Ecological Impact:

    • Habitat Destruction: Mining on the continental shelf and deep seabed can destroy fragile ecosystems like coral reefs and benthic habitats. Oil spills, like the Deepwater Horizon spill (2010) in the Gulf of Mexico, have devastating impacts on marine life, wetlands, and coastal economies.
    • Unsustainable Fishing: Practices like Bottom Trawling, where heavy nets are dragged across the seafloor, cause widespread destruction of marine habitats and lead to high levels of bycatch (unwanted species).

FISHING RESOURCES

  • Conditions Favorable for the Fishing Sector (Fishing Grounds)

    • Mixing of Currents: The confluence of warm and cold ocean currents creates ideal conditions for plankton growth, which forms the base of the marine food web, attracting large fish populations.
      • Example: The Grand Banks off Newfoundland, where the cold Labrador Current meets the warm Gulf Stream.
      • Example: Off the coast of Japan, where the cold Oyashio Current meets the warm Kuroshio Current.
    • Upwelling Zones: The movement of cold, nutrient-rich water from the deep ocean to the surface supports explosive growth of phytoplankton.
      • Example: The coast of Peru and Chile, influenced by the Humboldt (Peru) Current.
    • Shallow Continental Shelves: Wide and shallow shelves (less than 200m deep) allow sunlight to penetrate, promoting photosynthesis and plankton growth.
      • Example: The Dogger Bank in the North Sea, off the coast of Western Europe.
    • Ocean Current Circulation: Continuous circulation distributes nutrients, oxygenates water, and influences fish migration patterns.
    • Coral Reefs: These “rainforests of the sea” provide critical habitats and breeding grounds for a diverse array of fish species. Prominent in South and Southeast Asia.

  • Conditions Favorable for the Fishing Industry (Commercial Exploitation)

    • Temperature: Moderate temperatures of temperate regions aid in fish preservation, reducing spoilage and the need for immediate, expensive cold storage. Conversely, high temperatures in tropical regions lead to rapid decomposition, and while they support high biodiversity, this lack of uniformity can be a disadvantage for large-scale industrial fishing which often targets specific species.
    • Geography:
      • Coastline: A broken or indented coastline (a submergent coast) provides numerous natural harbours and sheltered areas for fishing fleets.
      • Land Use: Fishing often becomes a primary economic activity in regions where the land is rugged or unsuitable for agriculture, as seen in countries like Japan and Norway.
    • Economy: The development of a modern fishing industry requires significant investment in infrastructure like cold storage, processing plants, modern trawlers, and efficient transport networks. Less developed economies often struggle with these requirements.

DISTRIBUTION OF FISHING INDUSTRY

  • Major Fishing Grounds:

    • North-West Atlantic: Centered around Newfoundland (Grand Banks, George’s Bank), benefiting from the Labrador-Gulf Stream convergence.
    • North-East Atlantic: Extends from Spain to Norway, including the North Sea (Dogger Bank), benefiting from a wide continental shelf and the mixing of the warm North Atlantic Drift with cold Arctic waters.
    • North-West Pacific: Surrounding Japan and Korea, a result of the Kuroshio-Oyashio current convergence.
    • North-East Pacific: Along the western coasts of Canada and the USA, influenced by the cold California Current and a broken coastline.
    • Central and Eastern Pacific: Off the coasts of Peru and Chile, one of the world’s most productive regions due to upwelling caused by the Humboldt Current.

  • Indian Fishing Sector’s Potential

    • A long coastline of approximately 7,517 km and a vast Exclusive Economic Zone (EEZ).
    • A wider continental shelf along the western coast compared to the eastern coast.
    • Significant potential for inland fishing (aquaculture) in rivers, lakes, and ponds. India is a major producer of freshwater fish.
    • The broken coastline on the West Coast is suitable for developing harbours.
    • India is the second-largest fish producer in the world (after China), combining marine and inland fisheries.

  • Issues in the Indian Fishing Sector

    • Cultural Factors: A significant portion of the Indian population is vegetarian, which limits domestic demand compared to countries in Southeast Asia or Europe.
    • Infrastructure Deficit: Lack of adequate cold storage, processing facilities, and efficient supply chains leads to post-harvest losses. Investment in the sector remains low.
    • Unorganized Nature: The sector is dominated by small-scale, traditional fishers. It is often a caste-based occupation, facing social and economic marginalization.
    • Outdated Technology: Widespread use of traditional boats and gear limits efficiency and catch capacity.
    • Market Focus: The sector often does not target high-value fish species, making it less competitive in international export markets.
    • Climatic Vulnerability: The fishing season is severely affected by the monsoon and the increasing frequency of cyclones.
    • Underdeveloped Processing Industry: Limited value addition through processing means lower economic returns.
    • Territorial Disputes: Frequent conflicts with neighbouring countries, such as with Sri Lanka over fishing rights in the Palk Strait, and disputes over maritime boundaries like Sir Creek with Pakistan.
    • IUU Fishing: Illegal, Unreported, and Unregulated (IUU) fishing by both domestic and foreign vessels depletes stocks and undermines sustainable management.
    • Climate Change Impact: Rising sea temperatures, ocean acidification, and altered currents are disrupting marine ecosystems, affecting fish stocks and migration patterns.

Prelims Pointers

  • Nitrogen Deficiency: All Indian soils are generally deficient in Nitrogen.
  • Iron Rich Soils: Laterite and Red soils are rich in iron.
  • Humus Rich Soils: Black soil, Mountain & Forest soil, and Peaty soil have high humus content.
  • Saline Soils: Arid soils are characterized by high salt content due to evaporation.
  • Black Soil Colour: The black colour is due to the presence of titaniferous magnetite.
  • Red Soil Parent Rock: Granite and Gneiss.
  • Laterite Soil Formation: Formed by Laterization (heavy leaching) in areas of high temperature and high precipitation.
  • Laterite Soil Acidity: They are slightly acidic in nature.
  • Laterite Soil Crops: Suitable for plantation crops like coffee, tea, and rubber.
  • Black Soil Parent Rock: Basaltic magma of the Deccan Trap.
  • Self-Ploughing Soil: Black soil is called self-ploughing soil due to its cracking property when dry.
  • Alluvial Soil: Formed by the deposition of river sediments; covers the northern and coastal plains.
  • Mountain Soil: Thin-layered and acidic due to slow decomposition of organic matter.
  • Peaty Soil: Found in waterlogged conditions like deltas and estuaries; high in organic matter.
  • Ocean Mineral Resources:
    • Dissolved: Common salt (NaCl), Magnesium, Bromine salts.
    • Deposited (Continental Shelf): Monazite sand (source of Thorium and Rare Earth Elements) found on the Kerala coast and the eastern coast of India.
    • Deposited (Deep Ocean): Polymetallic Nodules (PMN) and Polymetallic Sulphides.
  • PMN Composition: Rich in Manganese, Iron, Nickel, Cobalt, and Copper.
  • PMN Location: Central Indian Ocean Basin (CIOB), Clarion-Clipperton Zone (Pacific).
  • Ocean Energy Resources:
    • Tidal Energy Potential in India: Highest in the Gulf of Kutch and Gulf of Khambhat (Gujarat).
    • OTEC: Requires a temperature difference of at least 20°C between surface and deep water.
    • Monazite Sand: Source of Thorium for nuclear energy.
  • Desalination Technology in India: The National Institute of Ocean Technology (NIOT) developed Low-Temperature Thermal Desalination (LTTD).
  • Major Fishing Grounds (Global):
    • Grand Banks: Confluence of Labrador Current (cold) and Gulf Stream (warm).
    • Japanese Coast: Confluence of Oyashio Current (cold) and Kuroshio Current (warm).
    • Peruvian Coast: Upwelling due to the Humboldt Current (cold).
    • North Sea (Dogger Bank): Wide continental shelf.
  • India’s Fish Production Rank: Second largest in the world, after China.

Mains Insights

GS Paper I (Geography & Society)

  1. Soil Degradation and its Impact on Indian Agriculture:

    • Cause-Effect: The inherent deficiency of nitrogen and humus in major Indian soils (Alluvial, Red) coupled with intensive agricultural practices (Green Revolution) has led to widespread soil degradation. This results in declining crop yields, increased fertilizer costs for farmers, and threats to long-term food security.
    • Interlinkage: Soil health is directly linked to the agrarian crisis. Salinization in arid regions (due to over-irrigation) and acidification of forest soils impact the livelihoods of farmers and tribal communities respectively.
    • Government Initiatives: Discuss the efficacy of schemes like the Soil Health Card Scheme in addressing these micro-nutrient deficiencies and promoting balanced fertilization.

  2. Regional Disparities based on Soil Types:

    • The distribution of soils has historically shaped cropping patterns and economic development. The fertile Alluvial plains support intensive grain cultivation (wheat, rice), while the Black soils of the Deccan are ideal for cotton, creating distinct agro-economic zones. Laterite soil regions, though less fertile for food crops, have developed plantation economies. This analysis can be used to explain regional variations in agricultural prosperity and challenges.

GS Paper II (Governance & International Relations)

  1. Geopolitics of Deep-Sea Mining:

    • Governance Structure: The UN Convention on the Law of the Sea (UNCLOS) and the International Seabed Authority (ISA) regulate deep-sea mining in areas beyond national jurisdiction. The principle of “common heritage of mankind” is central but contested.
    • Strategic Imperative for India: India’s exclusive rights to explore PMNs in the Central Indian Ocean Basin (CIOB) are a strategic asset. It reduces import dependency for critical minerals (cobalt, nickel) essential for battery technology and the green transition. This is a key component of India’s ‘Blue Economy’ policy and its strategic competition with China in the Indian Ocean Region.
    • Debate: There is a significant global debate between technologically advanced nations pushing for exploitation and developing nations/environmental groups advocating for a precautionary approach due to unknown ecological impacts. This reflects a classic North-South divide.

  2. Trans-boundary Resource Disputes:

    • The issue of fishermen’s rights, particularly between India and Sri Lanka in the Palk Strait, is a recurring diplomatic challenge. It is not just a livelihood issue but also involves aspects of maritime security, resource depletion (due to bottom trawling by Indian vessels), and national sovereignty. A nuanced solution requires diplomatic engagement, joint resource management, and promoting alternative livelihoods.

GS Paper III (Economy, Environment & Technology)

  1. The Blue Economy: Potential vs. Perils:

    • Potential: Oceanic resources offer immense economic potential for India through energy (offshore wind, tidal), minerals (PMNs, REEs), food (fisheries, aquaculture), and transportation. The ‘Sagarmala’ and ‘Deep Ocean Mission’ are steps to harness this potential.
    • Perils (Challenges): The extraction is fraught with challenges:
      • Technological: Lack of indigenous deep-sea mining technology (being addressed by Samudrayaan Mission).
      • Economic: High cost and commercial non-viability of technologies like OTEC.
      • Environmental: The risk of irreversible damage to deep-sea ecosystems is a major concern. The “Precautionary Principle” must be applied. A robust environmental impact assessment framework is necessary before commercial exploitation begins.

  2. Reforming the Indian Fishing Sector:

    • Problem Analysis: The sector is characterized by a “dualistic” nature: a small, mechanized, export-oriented fleet and a large, traditional, subsistence-level fishing community. The key issues are not just low productivity but also social inequity, infrastructural gaps, and resource sustainability.
    • Policy Suggestions:
      • Formalization & Organization: Promote fishermen cooperatives (like AMUL model) to improve bargaining power, access to credit, and technology.
      • Infrastructure Development: Invest in cold chains, modern harbours, and fish processing units under the Pradhan Mantri Matsya Sampada Yojana (PMMSY).
      • Sustainable Practices: Regulate destructive practices like bottom trawling and enforce fishing holidays to allow stocks to replenish. Promote seaweed cultivation and mariculture as alternative livelihoods.
      • Tackling IUU: Enhance maritime surveillance and use technology (e.g., satellite monitoring) to curb Illegal, Unreported, and Unregulated fishing.

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