Paddy stubble burning is found to be a major contributor to Delhi’s air pollution.
Bans and fines are unlikely to be effective.
To devise a policy with a chance to succeed, one needs to understand the reasons why farmers prefer burning.
Why stubble burning is bad?
It causes smoke and particulate pollution that can move over long distance.
It also implies loss of nutrients in soil.
One tonne of straw when burnt releases 3 kg of particulate matter, 60 kg of carbon monoxide, 1,460 kg of carbon dioxide, 199 kg of ash and 2 kg of sulphur dioxide.
In Punjab alone, 15 million tonnes of paddy straw is burnt every year, generating 45 million tonnes of particulates.
Even after a stiff fine by Punjab and Haryana farmers still chose the option stubble burning.
Why farmers choose stubble burning?
When manually harvested, the crops can be cut at the bottom and the stalks could be sent for other uses such as paper mills, animal bedding, etc.
But manual harvesting has become very expensive as labourers charge around Rs 4,000/acre and take three to four days.
So at present, paddy harvesting is done by combine harvester machine, which finishes it in half an hour and charges Rs 1,200/acre.
But it leaves two thirds of the stalks on the ground.
So stubble burning is the cheapest and quickest way to get their fields ready in time for the sowing of next crop.
It kills weeds including those resistant to herbicides.
It also kills slugs and other pests.
What are the alternate uses of stubble?
Properly cut Stubble can be used to make bio-char or cellulosic ethanol, burn in a power plant or plant the next crop without tillage.
Bio-char is a fine-grained, carbon-rich, porous product remaining after straw has been subjected to pyrolysis at low temperatures in an environment with little or no oxygen.
Bio-char can improve water retention and increased soil surface area when used with other fertilisers.
What can be a viable solution?
A farmer’s economic compulsions dominate his decision to burn stubble.
Incentives from power generators and ethanol manufactures to farmers bringing stubble will provide solution for this.
Super SMS (straw management system) is an attachment that fits onto the combine harvesters for paddy, spreads residue evenly over the field.
It should be deployed while cutting the stubbles.
Initiatives should be taken to market biochar as a nutrient and private players should be involved for the infrastructures required.
