Environment and ecology
Biochar: Turning Farm Waste into ‘Black Gold’
India’s Agricultural Paradox
- Large quantities of agricultural biomass that could enrich soils are instead burned.
- Punjab and Haryana burn over 20 million tonnes of paddy straw annually due to short post-harvest windows and lack of viable alternatives.
- Residue burning releases greenhouse gases and particulate matter, causing severe air pollution and loss of valuable organic matter.
Declining Soil Health
- Many agricultural regions, from Maharashtra’s black soils to Kerala’s red soils, suffer from:
- Low soil organic carbon,
- Poor water-holding capacity,
- Rapid nutrient depletion.
- These factors reduce crop productivity despite improved seeds and irrigation.
Biochar
- Biochar is produced by heating agricultural waste under low-oxygen conditions (pyrolysis).
- The process yields a carbon-rich material that decomposes very slowly, enabling long-term carbon storage.
- It is considered a carbon-negative technology.
Benefits of Biochar
- Enhances soil structure and microbial activity.
- Improves water retention and nutrient-use efficiency.
- Increases crop yields by 10–30%.
- Raises water-holding capacity by 10–25%, especially in nutrient-poor soils.
- Helps maintain soil fertility and crop productivity over the long term.
Successful Field Studies in India
- In Akola district, Maharashtra, biochar from maize stalks improved soil organic carbon and fertility.
- Studies in Kerala found that biochar made from coconut leaf stalks enhanced soil quality across different cropping systems.
- Emphasizes the importance of utilizing locally available biomass resources.
Supporting Climate-Resilient Agriculture
- Biochar can help crops withstand droughts, heatwaves, and erratic rainfall.
- Reduces dependence on external agricultural inputs.
- Particularly beneficial for small and marginal farmers vulnerable to climate change.
- Can complement initiatives on:
- Natural farming,
- Soil health management,
- Carbon farming.
Carbon Credit Opportunities
- Biochar can be integrated into carbon credit markets, creating economic incentives for farmers and cooperatives.
- It qualifies as a persistent carbon dioxide removal technology under international standards.
- Under the VM0042 Agricultural Land Management Methodology, each tonne of certified biochar can generate 2–2.8 tonnes of CO₂-equivalent carbon credits.
- Carbon credits can provide an additional source of income.
Indian Innovation: KISAN Kiln
- Projects using the KISAN kiln, developed by IIT-Kharagpur, enable small farmers to convert farm waste into biochar and earn revenue from carbon markets.
Utilising Urban Organic Waste
- Biochar feedstock is not limited to crop residues.
- It can also be produced from:
- Municipal biodegradable waste,
- Sewage sludge,
- Other organic waste streams.
- India generates about 62 million tonnes of municipal solid waste annually, with over 50% being biodegradable.
Promoting a Circular Economy
- Converting organic waste into biochar diverts waste from landfills and reduces methane emissions.
- Supports sustainable agriculture while contributing to climate mitigation
