Biochar is a carbon-rich material produced by heating biomass such as crop residue, wood waste, husk, manure or other organic waste in a low-oxygen environment. This process is called pyrolysis.
It looks like charcoal, but its purpose is different. Charcoal is mainly used as fuel, while biochar is mainly used for soil improvement, carbon sequestration, waste management and pollution control.
How Biochar Is Made
Biochar is produced when biomass is heated in limited oxygen. Because oxygen is restricted, the biomass does not burn completely. Instead, it breaks down into a stable carbon-rich solid.
The process can produce:
- Biochar: solid carbon-rich material
- Bio-oil: liquid by-product
- Syngas: gas that can be used for energy
Common raw materials include:
- paddy straw
- rice husk
- sugarcane bagasse
- cotton stalk
- coconut shells
- bamboo waste
- wood chips
- animal manure
- municipal organic waste
The Government of India has described biochar as a carbon-rich material made by heating biomass such as crop residues or wood waste under low-oxygen conditions. It also notes that engineered biochar can be further treated to improve soil fertility, water retention and nutrient-use efficiency.
Why It Is Important
Biochar is important because it connects agriculture, climate action and circular economy.
Instead of burning crop residue in the open field, biomass can be converted into biochar. This reduces air pollution and creates a useful soil amendment.
Its importance lies in:
- converting farm waste into useful material
- improving soil quality
- storing carbon in soil for long periods
- reducing crop-residue burning
- improving water retention in dry soils
- reducing nutrient loss
- supporting circular economy in agriculture
A 2026 government note on circular economy in agriculture highlighted composting, biochar use and biomass recycling as practices that enhance soil fertility and improve agricultural circularity.
Biochar and Soil Health
Biochar improves soil by changing its physical and chemical properties.
It can make soil more porous, which improves aeration and water-holding capacity. It can also help retain nutrients, especially in degraded or sandy soils where nutrients are easily washed away.
In agriculture, biochar may help:
- improve water retention
- reduce fertiliser loss
- improve soil structure
- support microbial activity
- reduce soil acidity in some cases
- improve nutrient-use efficiency
- reduce erosion and nutrient leaching
Recent scientific reviews note that biochar can improve soil carbon sequestration, nutrient retention, water retention, pH regulation and soil productivity, though results depend on soil type, feedstock and production conditions.
Biochar and Carbon Sequestration
Biochar is also important as a carbon dioxide removal method.
When plants grow, they absorb carbon dioxide from the atmosphere. If crop residue decomposes or burns, much of that carbon returns quickly to the atmosphere. But when biomass is converted into biochar, a part of the carbon becomes more stable and can remain locked in the soil for decades or even centuries.
This makes biochar useful for:
- long-term carbon storage
- soil carbon enhancement
- carbon-credit generation
- climate-change mitigation
- reducing open biomass burning
The IPCC has discussed biochar as part of soil carbon sequestration and negative-emission pathways, especially when sustainably produced and applied.
India’s Relevance
Biochar is highly relevant for India because India produces large quantities of agricultural residue every year. Much of this residue is either burned, wasted or underutilised.
Biochar can be especially useful in regions affected by:
- crop-residue burning
- declining soil organic carbon
- water-stressed agriculture
- degraded soils
- high fertiliser dependence
- air pollution from biomass burning
In states like Punjab, Haryana, Uttar Pradesh and parts of Rajasthan, crop-residue management is a major air-quality issue. In dryland and rainfed regions, biochar can help improve water retention and soil resilience.
Link with Carbon Markets
Biochar is gaining attention because it can generate carbon-removal credits.
In 2025, Google signed a deal with Indian supplier Varaha to buy 100,000 tonnes of carbon credits by 2030 from a project that converts agricultural waste from Indian farms into biochar. Reuters reported this as Google’s first major entry into India’s carbon dioxide removal sector.
This is important because it shows that biochar is no longer only an agricultural input. It is also becoming part of the climate-finance and carbon-credit economy.
Uses of Biochar
Biochar has multiple uses beyond soil improvement.
Important uses include:
- Agriculture: soil amendment, water retention, nutrient retention
- Climate action: carbon sequestration and carbon-credit generation
- Waste management: conversion of crop residue and biomass waste
- Pollution control: adsorption of pollutants from water and soil
- Composting: improves compost quality and reduces odour
- Livestock: may be used in bedding or manure management systems
- Energy systems: pyrolysis by-products like syngas can support decentralised energy
Its use in wastewater treatment is also being studied because biochar can adsorb certain pollutants, nutrients and heavy metals depending on how it is produced and modified.
Engineered Biochar
Engineered biochar is biochar that is modified or treated to improve specific properties.
For example, biochar can be engineered to:
- improve nutrient retention
- adsorb heavy metals
- improve water purification
- increase surface area
- enhance microbial activity
- improve fertiliser efficiency
This makes engineered biochar useful not only in agriculture, but also in environmental remediation and wastewater treatment.
Benefits
Biochar has several advantages when produced and applied properly.
Its benefits include:
- reduces open burning of crop residue
- improves soil health
- stores carbon in a stable form
- improves water retention
- reduces fertiliser loss
- supports circular economy
- creates rural enterprise opportunities
- can generate carbon credits
- helps manage agricultural waste
For farmers, the immediate value depends on yield improvement, reduced input cost and soil resilience. For climate policy, the value lies in durable carbon storage.
Limitations
Biochar is promising, but it is not a magic solution.
Its performance depends on feedstock, pyrolysis temperature, soil type, climate, crop and application rate. Poor-quality biochar may not improve soil and may even create problems if contaminated biomass is used.
Major limitations include:
- high initial cost of pyrolysis units
- lack of standard quality norms
- difficulty in measuring long-term carbon storage
- transport cost of bulky biomass
- uncertain yield response across soils
- risk of contamination from polluted feedstock
- need for farmer training
- weak market linkage for biochar products
There is also a concern that carbon-removal credits should not become an excuse for companies to delay direct emission cuts. Critics have warned that biochar-based carbon removal must be used carefully and should not replace actual emission reduction.
Policy Relevance
Biochar fits into several policy areas in India.
It is relevant for:
- crop-residue management
- soil health improvement
- natural farming and sustainable agriculture
- circular economy
- carbon markets
- climate mitigation
- rural entrepreneurship
- waste-to-wealth initiatives
For large-scale use, India will need clear standards for biochar quality, reliable carbon-accounting methods, farmer-level demonstrations, affordable pyrolysis technologies and integration with crop-residue management schemes.
Way Forward
Biochar should be promoted where it gives both agricultural and environmental benefits.
India can scale biochar through:
- village-level biomass pyrolysis units
- farmer producer organisations
- crop-residue collection systems
- carbon-credit aggregation for small farmers
- soil-specific biochar recommendations
- quality certification
- research on Indian soils and crops
- integration with composting and organic farming
The strongest use case is not simply producing biochar anywhere, but matching the right biomass, right production method and right soil condition. Done properly, biochar can turn agricultural waste into a tool for soil health, climate action and rural income.
