Nature and Major Gases
Agricultural greenhouse gas emissions arise from crop production, livestock rearing, fertiliser use, farm energy consumption and changes in land use.
The principal gases are:
- Methane, mainly from livestock digestion, manure and flooded rice fields
- Nitrous oxide, mainly from nitrogen fertilisers, manure and agricultural soils
- Carbon dioxide, mainly from land-use change, machinery, irrigation and energy use
Agriculture is different from many industrial sectors because a large share of its emissions comes from biological processes rather than direct fossil-fuel combustion.
Major Sources
Livestock
Ruminant animals such as cattle, buffaloes, sheep and goats produce methane during digestion through a process called enteric fermentation. Improperly managed manure also releases methane and nitrous oxide.
Rice cultivation
Continuously flooded paddy fields create oxygen-deficient conditions in which microorganisms break down organic matter and release methane.
Agricultural soils
The application of synthetic fertilisers and animal manure increases nitrogen in the soil. Microbial processes can convert part of this nitrogen into nitrous oxide.
Crop-residue burning
Burning agricultural residue releases carbon dioxide, methane, nitrous oxide and air pollutants such as particulate matter.
Land-use change
Conversion of forests, grasslands and wetlands into agricultural land releases stored carbon and reduces the capacity of ecosystems to absorb carbon dioxide.
Farm energy use
Diesel pumps, tractors, machinery, cold storage and fertiliser production contribute indirectly or directly to carbon dioxide emissions.
Environmental and Economic Effects
Agricultural emissions contribute to global warming and can also affect soil, air and water quality.
Methane is a powerful short-lived greenhouse gas, while nitrous oxide has a much longer atmospheric lifetime and a high warming effect.
Climate change, in turn, affects agriculture through:
- irregular monsoon rainfall;
- droughts and floods;
- heat stress;
- declining crop yields;
- increased pest attacks;
- livestock health problems;
- greater irrigation demand.
Agriculture is therefore both a contributor to and a victim of climate change.
Emission-control policies must protect food security and farmer incomes. Measures that raise production costs without providing financial and technical support may disproportionately affect small and marginal farmers.
Mitigation Measures
Improved rice cultivation
Alternate wetting and drying, direct-seeded rice and better water management can reduce methane emissions while conserving irrigation water.
Efficient fertiliser use
Measures include:
- soil testing;
- balanced nutrient application;
- precision farming;
- split application of nitrogen;
- use of organic and slow-release fertilisers;
- promotion of neem-coated urea.
Livestock management
Better feed quality, improved animal health, scientific breeding and manure management can reduce emissions per unit of milk or meat.
Dung and other organic waste can be processed in biogas plants to produce clean fuel and organic manure.
Crop-residue management
Residue can be converted into compost, bioenergy, animal feed, biochar or industrial raw material instead of being burnt.
Carbon sequestration
Agroforestry, conservation agriculture, cover crops, restoration of degraded land and improved soil-organic matter can increase carbon storage.
Indian Context and Way Forward
India’s agricultural emissions are strongly influenced by its large livestock population, extensive rice cultivation and widespread use of nitrogen fertilisers.
The mitigation approach must focus on reducing the emissions intensity of agriculture rather than reducing food production or livestock-based livelihoods.
Important priorities include:
- climate-resilient crop varieties;
- efficient irrigation;
- farmer access to low-emission technologies;
- expansion of biogas and organic-waste management;
- better agricultural-extension services;
- financial incentives for sustainable practices;
- reliable measurement of farm-level emissions;
- integration of mitigation with adaptation.
Policies must account for regional differences. Rice-producing regions, dryland agriculture, dairy areas and plantation systems require different solutions.
Conclusion
Agricultural greenhouse gas emissions arise mainly from livestock, rice fields, fertilisers and land-use change. Their reduction requires changes in farm practices, technology and resource management without compromising food security or rural livelihoods.
