Notes on "Climate Resilient Agriculture":

Introduction:

• Climate change: Major environmental issue of the 21st century with long-term weather pattern changes.
• Influences: Natural (solar radiation, volcanism) and human activities (industrial revolution effects).
• IPCC 2007 findings: Increased frequency/intensity of extreme weather events over the last 50 years.

Greenhouse Gases and Global Warming:

• Causes: Fast-paced development, industrialization, and environmental destruction.
• Greenhouse gases: CO2, CH4, N2O; different lifetimes, radiative forcing, and atmospheric concentrations.
• Greenhouse effect: Traps heat, leading to global warming and regional climate changes.
• GHG sources: Solar, volcanic, and biospheric/industrial.
• Major anthropogenic CO2 sources: Biosphere, burning of fossil fuels, deforestation.
• Projected impacts by 2100: Temperature rise 1.4 to 5.8°C, decreased rainfall in sub-tropics, increased extreme events.

Climate Variability Including Extreme Events:

• Definition: Yearly fluctuation of climate above/below a long-term average.
• Climate extremes: Drought, untimely rainfall, floods, heat/cold waves, frost, hailstorms, cyclones.
• Impact: Affects crop area, performance, yield, and overall agricultural production.

Droughts:

• Types: Meteorological, hydrological, agricultural, socio-economic.
• India Meteorological Department (IMD) criteria: Rainfall deficit and drought classification.

Untimely Rainfall/High Intense Rainfall Events:

• Recent trends: Continuous high rainfall leading to crop losses, pest outbreaks, total crop failure.

Floods:

• Common in Indian river basins and coastal areas.
• Effects: Physical crop loss, land degradation, soil erosion.

Heat Wave:

• Definition: Exceeding normal temperatures for a duration in specific regions.
• Impacts: Affect growth, flowering, fruiting, and crop mortality.

Cold Wave:

• Definition: Below normal minimum temperatures for a duration in specific regions.
• Impacts: Affect growth, flowering, and ripening of crops.

Frost:

• Occurrence: Surface temperature falls below freezing.
• Impact: Affects plant growth and productivity.

Hailstorm:

• Definition: Weather condition where hail falls to the ground.

Cyclone:

• Origin: Tropical low pressure depression with oceanic temperature above 26°C.
• Impacts: Crop inundation, seawater intrusion.

Climate Change Effects on Crops:

• Direct effects: Plant growth, yield changes due to temperature, rainfall, CO2 levels.
• Indirect effects: Land use changes, water availability, soil transformations, pest infestations.

Effect of Climate Change on Photosynthesis, C3 and C4 Crops:

• Impact on photosynthesis: Varies with CO2 levels and temperature.
• C3 plants: More responsive to CO2 increase.
• C4 plants: Less responsive due to CO2 concentrating mechanism.
• Temperature effects: Significant on crop phenology, yield reduction in C3 crops with temperature increase.

Effect of Climate Change on Crop Production:

• Atmospheric CO2 increase: Promotes growth in C3 plants, affects crop duration and respiration rates.
• Temperature rise: Reduces yields in warmer regions, affects crop-pest equilibrium.
• Variable impacts: Different for each crop; e.g., cotton resilient to high temperatures but sensitive to water availability.

Climate Change Effects on Soils:

• Potential changes: Organic matter supply, temperature regimes, hydrology, evapotranspiration.
• Impacts: Soil moisture stress, workability, erosion, compaction, water holding capacity.

Climate Change Effects on Insect-pests:

• Increased temperature: Affects insect-pest populations, host plant interactions, and pest status changes.

Climate Change Effects on Diseases:

• Temperature and UV radiation changes: May reduce effectiveness of natural and synthetic pesticides.

Climate Change Effects on Weeds:

• Spread of tropical/subtropical weeds into temperate areas.
• Rainfall pattern changes: Alter water availability and weed shifts.

Climate Resilient Agriculture:

• Definition: Incorporation of adaptation, mitigation practices in agriculture.
• Goal: Increase system capacity to resist damage and recover from climate disturbances.

Adaptation:

• IPCC definition: Adjustments in response to climate stimuli.
• Types: Reactive/anticipatory, private/public, planned/autonomous.
• Adaptation in agriculture: Adjusts to minimize damage, promotes sustainable development.

Mitigation:

• Efforts to reduce/prevent greenhouse gas emissions.
• Strategies: New technologies, energy efficiency improvements, management practice changes.

Agro-Techniques for Adaptation to Climate Change:

• Crop Management Strategies: Tillage practices, crop and cultivar choices.
• Contingency crop planning: Alternate crop choices based on rainfall and soil moisture.
• Water Management Strategies: Harvesting rainwater, runoff, and improving irrigation efficiency.

Agro-Techniques to Mitigate Climate Change:

• Crop Management: Reducing GHG emissions through improved agronomic practices.
• Nutrient Management: Reducing nitrous oxide emissions with efficient management practices.
• Tillage/Residue Management: Enhancing soil carbon sequestration through reduced tillage.

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