"Decentralised Biochar Units Proposed to Resolve Punjab Stubble Burning"
Biochar
carbon-rich material made by heating biomass under limited oxygen; improves soil and sequesters carbon.
Pyrolysis
thermal decomposition of biomass in low-oxygen conditions, producing biochar, bio-oil, and syngas.
Every post-harvest season, Punjab and Haryana generate millions of tonnes of paddy straw, locally called parali, that farmers burn to clear fields quickly before the wheat sowing window. This practice releases large quantities of particulate matter, carbon monoxide, and greenhouse gases, contributing significantly to the severe air quality crisis in the Indo-Gangetic Plain, including Delhi. Governments have responded with satellite monitoring, fines, and subsidies for Happy Seeder machines and other in-situ residue management tools. Yet burning continues, because the economics for individual farmers have not changed enough.
The paddy-wheat rotation in Punjab is itself a product of the Green Revolution and the Minimum Support Price (MSP) system. Assured procurement of rice and wheat by the Food Corporation of India (FCI) locked farmers into these two water-intensive crops. The same system that drove productivity gains now generates a residue problem that the state struggles to manage. Soil quality in Punjab has declined from decades of intensive cultivation, heavy fertiliser use, and groundwater depletion, making the agronomic case for soil amendment stronger than ever.
Crop residue management sits at the intersection of three GS3 themes: agricultural sustainability, rural value addition through processing, and environmental pollution. UPSC has repeatedly tested how food processing and decentralised rural industry can raise farmer incomes, and this article extends that logic to a non-food biomass stream.
Biochar is produced by heating biomass, including paddy straw, maize stalks, cotton stalks, and mustard stalks, in a low-oxygen environment through a process called pyrolysis. Roughly 100 kg of dry parali yields approximately 30 kg of biochar. Unlike direct combustion, which releases most of the biomass carbon back into the atmosphere as carbon dioxide, pyrolysis locks a significant share of carbon into a stable solid form. When applied to agricultural soil, biochar can persist for a century or longer, making it a genuine carbon sequestration tool.
Beyond carbon storage, biochar improves soil water retention and nutrient-use efficiency. For Punjab's degraded soils, this is directly relevant: the same residue that currently worsens air quality could, if processed into biochar and returned to fields, partially reverse soil health decline. This dual benefit, environmental (reduced burning, carbon sequestration) and agronomic (soil improvement), distinguishes biochar from simply using parali as fuel in Compressed Biogas (CBG) plants or biomass power stations, where the carbon is released as energy. …
What are the reasons for poor acceptance of cost-effective small processing units? How will food processing units help uplift the socio-economic status of poor farmers?
What are the challenges and opportunities of the food processing sector in India? How can income of farmers be substantially increased by encouraging food processing?
How do subsidies affect cropping pattern, crop diversity and economy of farmers? What is the significance of crop insurance, minimum support price and food processing for small and marginal farmers?
Consider the following statements regarding biochar production from crop residues:
1.Biochar is produced by heating biomass under limited oxygen conditions through a process called pyrolysis.
2.Approximately 100 kg of dry paddy straw yields around 30 kg of biochar.
3.Unlike direct combustion, biochar production returns most of the biomass carbon to the atmosphere.
4.Biochar applied to soil can sequester carbon for a century or longer.
How many of the above statements are correct?
With reference to paddy straw (parali) management in India, consider the following statements:
1.Parali burning is primarily driven by the narrow time window between rice harvest and wheat sowing.
2.The current biomass supply chain concentrates value addition at the farm level rather than at centralised processing facilities.
3.Biochar produced from paddy straw can improve soil water retention and nutrient-use efficiency.
Which of the statements given above is/are correct?
Consider the following pairs:
Crop residue use → Carbon outcome
1.Direct combustion of paddy straw → Most carbon returned to atmosphere as CO₂
2.Pyrolysis into biochar → Carbon locked in stable solid form in soil
3.Use in Compressed Biogas (CBG) plants → Carbon permanently sequestered underground
How many of the above pairs are correctly matched?
Which of the following best describes the 'build-operate-transfer (BOT)' model as proposed for village-scale biochar units in India?
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