Soil Acidification in India

GS-1 Mains (Geography)

Short Notes or Revision Notes 

Question :  Examine the causes and extent of soil acidification in India. Suggest Wayforwad.

What is it?

• Soil acidification is a decrease in soil pH over time.
• Caused by removal of base cations (Ca, Mg, K, Na) and their replacement with H+ and Al+ ions.
• Accelerated by intensive agriculture.

Causes:

• Natural:
  • Weathering of soil minerals releases H+ ions.
  • Rainwater has a naturally acidic pH (around 5.6).
• Anthropogenic:
  • High levels of ammonium-based fertilizers.
  • Long-term rainfall.
  • Draining sulfuric soils.
  • Acid deposition.
  • Removing all harvested materials.

Extent:

• Global:
  • Future warming could deplete soil inorganic carbon (SIC) by 1.35-5.83 GtC by 2100.
  • 13 billion tonnes of SIC lost from soils annually.
• India:
  • Over 30% of cultivable land is acidic (48 million hectares).
  • Widespread in humid southwest, northeast, and Himalayas.
  • Northeast India: 95% of soils are acidic.

Impacts:

• Depletes soil inorganic carbon (SIC), harming soil health and carbon storage.
• Reduces availability of plant nutrients, affecting crop growth and productivity.
• Increases susceptibility to other stresses.
• India: Potential loss of 3.3 billion tonnes of SIC in next 30 years.

Soil Carbon Types:

• Soil Inorganic Carbon (SIC): Mineral forms like calcium carbonate.
• Soil Organic Carbon (SOC): From plant/animal waste, microbes, etc.

Improving Acidic Soil:

• Sustainable methods: Compost, wood ash.
• Management strategies: Optimize fertilizer use, minimize leaching.
• Liming: Adding materials to neutralize acidity (Ca/Mg oxides, hydroxides, carbonates).

Government Initiatives:

• Soil Health Card Scheme: Provides info on soil nutrients for corrective measures.
• Paramparagat Krishi Vikas Yojana: Promotes organic farming to improve soil organic matter.
• Neem Coating of Urea: Slows down urea degradation and improves plant uptake.
• Save Soil Movement: Aims for chemical-free soil, healthy soil organisms, moisture conservation, reduced groundwater depletion, and minimized soil erosion.

Conclusion:

• Soil acidification is a serious threat to soil health, productivity, and livelihoods.
• Sustainable practices and effective management are crucial to mitigate its impacts.