The pollution level in Delhi reached unprecedented levels this year. Paddy stubble burning in October and November is a major contributor to Delhi’s air pollution. Stubble burning also implies loss of nutrients. This cannot and should not go on and we need to take drastic measures. Punjab and Haryana have banned it, and a stiff fine is levied — Rs 2,500 for two acres and up to Rs 15,000 for larger areas. Despite this, stubble burning goes on. Stubble burning is fairly common in China too despite a government ban.
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. Today, paddy harvesting is done by harvester combines, which leave two thirds of the stalks on the ground. 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. However, manual harvesting has become very expensive. Labourers charge around Rs 4,000 per acre and take three to four days. A harvester combine does it in half an hour and charges Rs 1,200 per acre. Farmers burn paddy straw after the crop is harvested. It is the cheapest and quickest way to get their fields ready in time for the sowing of next crop.
Stubble burning has also some other advantages. It kills weeds including those resistant to herbicides. It also kills slugs and other pests. On the other hand, it causes smoke and particulate pollution that can move over long distance. A farmer’s economic compulsions dominate his decision. Thus to check stubble burning, we need to find a way that provides him economic incentive to cease from it.
In Punjab alone, 15 million tonnes of paddy straw is burnt every year. Because of good monsoon, the amount may be larger this year. This is done over a period of 20 days and cause haze and low hanging clouds of smoke. This poses a lethal hazard. 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. Thus 15 million tonnes of paddy straw will generate 45 million tonnes of particulates.
Punjab and Haryana plant some 10.5 million acres of paddy. If the burning is to be stopped, farmers would want Rs 2,800 per acre, which is the extra cost of employing manual labour. So it will cost at least Rs 3,000 crore per year to stop paddy burning in Punjab and Haryana. If there is a demand for economical use of straw, it will be gathered and used, eliminating the need for burning. Can the potential uses create a market for straw?
Stubble can be used to make bio-char or cellulosic ethanol, burn in a power plant or plant the next crop without tillage. All of these, however, require first cutting the stubble. An attachment, Super SMS (straw management system) that fits onto the combine harvesters for paddy, spreads residue evenly over the field. Excepting the no tillage planting, others require that the stubble is gathered from the field, baled and transported to the plant site. An IFSL power plant purchases straw at Rs 1,200 to Rs 1,300 per tonne from traders who use their own machines to collect and bale straws. The farmers get around Rs 900 to Rs 1,000 per tonne. The cost of collection, transport, palletising etc. comes to Rs 2,000/tonne for the plant.
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 with its highly porous structure, improved water retention and increased soil surface area when used with other fertilisers, increases the yield by up to 30 per cent to 50 per cent for some soils and crops. Unfortunately for the soils of Punjab and Haryana, biochar is not likely to be very effective as a nutrient.
Another use of paddy straw will be as fuel in a power plant. A 12MW plant of IFCL in Patiala district with a capital cost at Rs 72 crore collects a lakh tonne of straw from a 50 km radial distance, operates for seven months and generates 5.5 crore kWh of electricity. The CERC fixed tariff of Rs 8.26/unit for such plants will make it economical. However, a subsidy of Rs 5 /kWh will be needed for consumers to buy the electricity. Around 10 to 12 power plants can cover the whole paddy-rice area in Punjab and Haryana. The total subsidy burden will be around Rs 330 crore per year.
HPCL is setting up a plant in Punjab to produce ethanol from paddy straw. The plant with an investment of Rs 600 crore will produce three crore litre of ethanol and generate around 70 million kWh of electricity using 1,50,000 tonne of paddy straw. Again to make this an economically viable option, subsidy of Rs 10 per litre of ethanol may be needed, requiring Rs 300 crore for 10 plants along with an effective blending policy.
No tillage planting of wheat an be done with a device named Happy Seeder. The data shows increase in wheat yield or at least no reduction in wheat yield. Somanathan and Gupta (IE, November 23) have estimated the initial cost of Happy Seeder and Super SMS to be around Rs 1,800 crore to cover the whole country. The annual subsidy required may be much smaller. Over eight years, the adopters have increased from less than a hundred to around 3,000.
Both power generation and cellulosic ethanol provide options that can be implemented quickly. Also they provide additional income to farmers for the paddy stubble. While power plant is a proven technology, cellulosic ethanol production is a new one but a very important technology for the country’s energy security and emission reduction.
A multipronged strategy is called for promoting power plants and ethanol production. Announce a policy of subsidy in the next month and encourage private entrepreneurs to set up these plants. Only then can we hope to reduce substantially stubble burning by next Diwali.