Biochar: Turning India's Farm Residue Fires Into 'Black Gold' for the Soil

Every post-harvest season, the skies over Punjab and Haryana turn grey as farmers torch more than 20 million tonnes of paddy straw in open fields. The practice is driven by narrow harvest windows and a near-absence of practical alternatives — yet the cost is enormous.

Burning crop residues releases significant quantities of greenhouse gases and fine particulate matter, fouling the air across northern India. Equally damaging but less visible is the loss of organic matter that is incinerated rather than returned to the soil. Meanwhile, agricultural land across the country — from Maharashtra's black soils to Kerala's red soils — already suffers from critically low soil organic carbon, weak water retention, and rapid nutrient loss. Higher-quality seeds and expanded irrigation have not been enough to arrest the decline in productivity. Both crises, researchers argue, are symptoms of the same systemic failure: India does not recycle its natural resources efficiently.

Biochar is produced through pyrolysis — heating agricultural waste in conditions where oxygen is severely restricted. The result is a carbon-dense, highly porous material that resists rapid decomposition, locking carbon into the soil for extended periods.

Its agronomic value goes well beyond carbon sequestration. The porous structure aggregates soil particles, improves water retention by 10%–25%, and creates a hospitable habitat for beneficial soil microorganisms. Studies indicate biochar can lift crop productivity by 10%–30% in nutrient-depleted soils.

Indian field trials reinforce these findings:

• Maharashtra (Akola district): Biochar derived from maize stalks, applied to black soils, improved soil organic carbon content and overall fertility.
• Kerala: Biochar produced from coconut leaf stalks enhanced soil quality across multiple cropping systems, demonstrating the value of using locally available feedstocks.

Long-term studies further show that these soil health gains are durable, sustaining higher crop output over time rather than delivering a one-season boost.

The economic argument for biochar hinges on carbon markets. Biochar carbon meets stringent stability criteria for long-term sequestration and qualifies as a persistent carbon dioxide removal technology under internationally recognised accounting frameworks.

The VM0042 agricultural land management methodology is particularly relevant: it quantifies both avoided emissions from residue burning and long-term soil carbon sequestration. Under this protocol, each tonne of certified biochar can generate 2–2.8 tonnes of CO₂-equivalent in tradeable carbon credits, providing additional income for project developers, farmer groups, and cooperatives — with the exact value depending on prevailing carbon market prices.

A domestic example already in operation is the KISAN kiln developed at IIT-Kharagpur, which is designed for smallholder use and enables farmers to monetise farm waste directly. International precedents are also instructive: Kenya converted rice husks into thousands of certified carbon credits while improving soil phosphorus and pH; Thailand embedded biochar certification within its national carbon registry; and Brazil's Embrapa Institute recorded high carbon retention and significant yield gains from on-farm biochar produced from sugarcane bagasse.

Agricultural residue is not the only raw material available. India generates approximately 62 million tonnes of municipal solid waste per year, of which more than half is biodegradable. Sewage sludge and urban organic waste can also be processed into biochar through pyrolysis.

This positions biochar within a broader circular economy framework: organic material that would otherwise decompose in landfills — generating methane, a potent greenhouse gas — is instead converted into a productive agricultural input. For urban local bodies grappling with waste management, and for agri-businesses seeking new input categories, this dual-feedstock model expands the addressable opportunity considerably.

Researchers emphasise, however, that scaling biochar successfully requires more than technology. It demands an integrated ecosystem that connects decentralised, appropriately sized pyrolysis units with robust measurement, reporting, and verification systems — and that creates reliable market linkages so farmers can access both biochar inputs and carbon credit revenues at an affordable cost.

Despite the weight of evidence, biochar remains largely confined to research stations and pilot schemes in India. Agricultural residues continue to be treated primarily as a disposal problem rather than a resource.

Researchers advocate for integrating biochar into existing government programmes — including natural farming initiatives, soil health management schemes, and emerging carbon farming frameworks — to unlock environmental and economic benefits at scale. A coherent policy-to-market pipeline, modelled partly on Thailand's experience of tying biochar certification to national carbon registry access, could be the catalyst needed.

Three priorities stand out:

• Formalising carbon credit pathways for biochar under Indian climate policy
• Supporting decentralised pyrolysis technology — such as the KISAN kiln — for small and marginal farmers
• Expanding feedstock sourcing to include urban organic waste, linking municipal waste management with agricultural soil improvement

For India's most climate-exposed farmers, the convergence of soil restoration, income generation, and climate mitigation that biochar offers is too significant to remain a laboratory curiosity.