Why in news: Recent studies highlight that Alternate Wetting and Drying (AWD) in paddy cultivation enhances water productivity, maintains high rice yields, and significantly reduces methane emissions, making it a climate-smart rice production practice.
What is Alternate Wetting and Drying (AWD)?
1AWD is a water-saving irrigation technique used in irrigated lowland rice.
2Unlike continuous flooding, paddy fields are intermittently dried and re-flooded based on soil water conditions.
3It reduces water use without compromising crop yield when properly managed.
How AWD Works (Mechanism)
- After irrigation, water is allowed to subside naturally.
- Fields are re-irrigated only when the water level drops to a specified depth below the soil surface (often measured using a perforated field water tube).
- This cycle of wetting and drying continues until the flowering stage, after which shallow flooding is usually resumed.
Why AWD Reduces Greenhouse Gas Emissions
- Methane (CH₄) in rice fields is produced due to anaerobic decomposition of organic matter under continuously flooded conditions.
- Temporary drainage introduces oxygen, disrupting anaerobic conditions.
- This suppresses methane-producing microbes, leading to lower CH₄ emissions.
- AWD can reduce methane emissions by 30–70%, depending on soil and management practices.
Benefits of AWD
1Water Efficiency
- Saves 15–30% irrigation water, improving water productivity.
- Particularly useful in water-stressed regions.
2Climate Mitigation:
- Reduces methane emissions, contributing to India’s climate commitments (NDCs).
3Agronomic Advantages
- Maintains or improves yields if applied correctly.
- Encourages deeper root growth and better nutrient uptake.
4Economic Benefits
- Lower irrigation costs.
- Reduced pumping energy use.
Challenges in Adoption
1Requires farmer awareness and training.
2Needs field-level monitoring of water depth.
3Risk of yield loss if drying exceeds critical thresholds.
4Institutional support needed for large-scale adoption.
Relevance for India
1Rice is a major water- and methane-intensive crop.
2AWD aligns with:
oNational Mission for Sustainable Agriculture
oClimate-Smart Agriculture
oWater conservation goals
3Important for states like Punjab, Haryana, Telangana, Andhra Pradesh, and Tamil Nadu.
IAS-2026 - OPTIONAL / GEOGRAPHY / PUBLIC ADMINISTRATION / SOCIOLOGY / ANTHROPOLOGY / ORIENTATION ON 03 & 04-10-2025 
