Agro-Climatic Classification of India

1. Agro-climatic classification is based on climate, soil, and physiographic conditions.
2. Purpose: To plan regional agricultural development and resource management.
3. Agro-climatic zones (Planning Commission, 1988): 15 zones.
4. Agro-ecological regions (ICAR-NBSS&LUP, 1992): 20 regions.
5. Agro-ecological sub-regions in India: 60.
6. Agro-climatic regions were classified by: Planning Commission (1988).
7. Agro-ecological regions were classified by: ICAR-NBSS&LUP (1992).
8. Basis of classification: Climate, length of growing period (LGP), soil type, physiography.
9. Length of Growing Period (LGP): Duration in days when soil moisture and temperature are suitable for crop growth.
10. LGP classification:
    • < 90 days → Arid
    • 90–180 days → Semi-arid
    • 180–270 days → Sub-humid
    • 270 days → Humid
11. India’s largest agro-climatic zone: Western Plateau and Hills Region.
12. Smallest agro-climatic zone: Western Himalayan Region.
13. ICAR’s 20 Agro-Ecological Regions are further divided into 60 subregions based on LGP and soil.
14. Agro-climatic zones help in crop planning, research station establishment, and weather advisory.
15. Agro-climatic region of Uttar Pradesh:
    • Western Plain Zone
    • Central Plain Zone
    • Eastern Plain Zone
    • Bundelkhand Zone
    • North Eastern Plain Zone

Indian Monsoon and Rainfall Facts

1. Monsoon means “seasonal reversal of winds.”
2. Word ‘Monsoon’ derived from: Arabic word “Mausim” meaning “season.”
3. Southwest Monsoon Season: June–September.
4. Northeast Monsoon Season: October–December.
5. Summer monsoon contributes ~75–80% of India’s annual rainfall.
6. Average annual rainfall of India: ~1180 mm.
7. Onset of Southwest Monsoon in India: Around 1st June (Kerala coast).
8. Withdrawal of Monsoon: Starts from northwest India in September.
9. Monsoon winds are divided into two branches:
   • Arabian Sea branch
   • Bay of Bengal branch
10. Arabian Sea branch brings rain to: Western coast & Western Ghats.
11. Bay of Bengal branch brings rain to: Eastern India and the Gangetic plains.
12. Heaviest rainfall in India: Mawsynram, Meghalaya (~11,871 mm).
13. Least rainfall area: Leh-Ladakh (<100 mm).
14. Break in Monsoon: Period when monsoon weakens temporarily.
15. Rain shadow region: Area receiving low rainfall due to obstruction by mountains (e.g., Deccan Plateau).
16. Monsoon onset and progress monitored by: India Meteorological Department (IMD).
17. ENSO (El Niño Southern Oscillation) affects monsoon variability.
18. El Niño years: Weak monsoon in India.
19. La Niña years: Strong monsoon and above-average rainfall.
20. Southwest monsoon covered area: Entire India except Tamil Nadu (mainly affected by NE monsoon).

Climatic Regions of India (Köppen Classification)

1. India lies in the tropical and subtropical zone.
2. Köppen classified world climate based on: Temperature and precipitation.
3. Main climatic regions of India:
   • Tropical wet (Monsoon)
   • Tropical dry (Semi-arid and arid)
   • Subtropical humid
   • Mountain climate
4. Western Rajasthan: Arid climate.
5. Punjab, Haryana, UP, Bihar: Semi-arid to sub-humid.
6. Northeast states: Humid to per-humid.
7. Himalayan region: Mountain climate with snowfall.
8. Coastal regions: Tropical wet.
9. Major climatic control factors: Latitude, altitude, distance from sea, ocean currents, and monsoon.
10. India’s climatic type according to Köppen: Tropical Monsoon Climate (Am).

Drought and Flood Management

🌵 Drought Facts

1. Drought: Period of prolonged dry weather leading to water shortage.
2. Types of drought:
   • Meteorological
   • Agricultural
   • Hydrological
   • Socio-economic
3. Meteorological drought: Rainfall < 75% of normal.
4. Agricultural drought: Soil moisture insufficient for crop growth.
5. Hydrological drought: Deficit in surface or groundwater supply.
6. Socio-economic drought: Water shortage affects livelihoods.
7. Deficit rainfall classification (IMD):
   • Normal: ±19%
   • Deficient: -20 to -59%
   • Scanty: -60 to -99%
   • No rain: -100%
8. India’s most drought-prone areas: Rajasthan, Gujarat, Maharashtra, Karnataka.
9. Meteorological drought year: Rainfall < 75% of normal.
10. Most drought-prone state: Rajasthan.
11. Drought-prone area in India: ~33% of geographical area.
12. Drought early warning monitored by: IMD and CRIDA (Hyderabad).
13. Drought index commonly used: Standardized Precipitation Index (SPI).
14. Other indices: Palmer Drought Severity Index (PDSI), Aridity Index.
15. Aridity Index (AI) = PET / Precipitation.
16. AI > 2 indicates extreme aridity.
17. Drought mitigation: Rainwater harvesting, mulching, drought-tolerant crops.
18. Major drought years in India: 1965, 1972, 1987, 2002, 2009.
19. Rajasthan & Gujarat experience drought once every 3 years.
20. Drought declaration based on rainfall, crop failure, and water availability.

Flood Facts

1. Flood: Overflow of water that submerges land not usually submerged.
2. Main causes: Heavy rainfall, river overflow, dam failure, deforestation.
3. India’s flood-prone area: ~40 million hectares.
4. Most flood-prone states: Bihar, Assam, West Bengal, UP.
5. River most prone to floods: Brahmaputra.
6. Flood management authorities: CWC (Central Water Commission), IMD, NDMA.
7. Flood forecasting centers established by: Central Water Commission (CWC).
8. Flood warning period: 24–48 hours before occurrence.
9. Flood mitigation measures: Embankments, reservoirs, afforestation.
10. Remote sensing and GIS – Used for flood monitoring and mapping.

Climate Change and Global Warming

1. Climate change – Long-term change in temperature and rainfall patterns.
2. Greenhouse gases (GHGs): CO₂, CH₄, N₂O, CFCs, O₃.
3. CO₂ contributes ~60% of total greenhouse effect.
4. Main causes: Fossil fuel burning, deforestation, industrialization.
5. Global warming potential (GWP):
   • CO₂ = 1
   • CH₄ = 25
   • N₂O = 298
   • CFCs = up to 10,000
6. IPCC (Intergovernmental Panel on Climate Change): Established in 1988.
7. UNFCCC (United Nations Framework Convention on Climate Change): 1992.
8. Kyoto Protocol: 1997 (entered into force 2005).
9. Paris Climate Agreement: 2015.
10. India’s nodal agency for climate change: MoEFCC (Ministry of Environment, Forest and Climate Change).
11. National Action Plan on Climate Change (NAPCC): 2008.
12. Important missions under NAPCC:
    • National Solar Mission
    • National Water Mission
    • National Mission on Sustainable Agriculture
13. Climate-smart agriculture: Integrates adaptation, mitigation, and productivity.
14. CO₂ Fertilization Effect: Increased CO₂ enhances photosynthesis in C₃ plants (e.g., wheat, rice).
15. Climate change impact: Shift in crop zones, pest outbreaks, and yield variability.
16. Mitigation: Carbon sequestration, afforestation, renewable energy use.
17. Adaptation: Drought-tolerant crops, early warning systems, water management.
18. Global temperature rise since 1880: ~1.1 °C.
19. Sea level rise per year: ~3.3 mm.
20. India’s National Innovation on Climate Resilient Agriculture (NICRA) – Launched by ICAR in 2011.