Why stubble burning? Because supply chain management is not efficiently managed

The governments of Punjab, Haryana and Uttar Pradesh have a crucial role to play in coordinating activities to ensure optimum supply chain management practices for paddy stubble. One would hope that in the last quarter of 2024, the stubble burning issue would no more be raised. The ball is clearly in the court of governments, says N.S. Venkataraman

Burning of paddy straw (stubble) in the last quarter of every year in Punjab, Haryana, Uttar Pradesh  and a few other states  have been a recurring issue for the past several years, causing a high level of pollution in these states as well as in  the capital city of New Delhi. As a result, New Delhi has gained notoriety as one of the most polluted cities in the world, which is not good for India’s image. A careful examination of the issues and possible solutions for solving the pollution-causing stubble-burning practice would highlight the fact that there is really no justification for the problem. The problem is there thanks to lack of forward planning and inefficient supply chain management.

It is reported that in Punjab alone, around 18 to 20 million tonnes of paddy straw is generated every year and about 15 million tonnes of paddy straw are burnt in open fields in a  few weeks, to clear the land for sowing wheat or other crops thereafter. There are plenty of things to be gained by avoiding the burning of stubble. Profit is one of them. Instead of focusing on finding long-term solutions to solve the issue, keeping in view the constraints and opportunities, only cosmetic measures have been adopted from time to time, when the pollution level would reach its peak due to stubble burning. 

Cosmetic steps are announced such as an odd-even scheme for taking out cars, declaring holidays for schools, asking people to work from home, suggesting a shift in crop pattern in the affected regions, attempting to get artificial rain and so on. For example, the attempt to alleviate severe pollution by resorting to artificial rain or cloud-seeding is an experimental endeavour with no evidence so far that it would be successful during non-monsoon months. Though cloud-seeding has been attempted in several regions earlier, it has been proved to be an almost wasteful exercise. Such schemes are cosmetic and seem to have been introduced  by the Delhi Government ‘to buy peace with the critics’.

The solutions are known but the problem has arisen due to lack of initiative and dynamism in facilitating the implementation of the solutions by the governments. The solutions can be broadly categorised as under:

• Use of  paddy straw as  organic  manure and  use it for organic farming
• Use of paddy straw to produce briquettes /  pellets to be used as fuel
• Use of paddy straw to produce ethanol by fermentation technology

Why stubble is burnt?
The paddy straw in the fields have to be cut and removed and the fields have to be cleaned in about two to three weeks time to allow for the planting of wheat or some other crop   thereafter. Cutting and removing the straw manually is costly and time-consuming and, therefore, machines are required. For collecting the paddy straw, governments have been providing subsidies to the farmers for  the purchase of machines including  surface-super-seeder machines, which are in situ paddy stubble management devices. The machines uproot the crop residue.  

It is reported that in Punjab which has more than 10 lakh farming families having land holdings of 2.5 acres or less, the families are not able to afford the machines. The machines are available to farmers at a rental of around Rs 1800 per acre. However, the machines are not available in adequate numbers, considering the extent of paddy farmland. In any case, small farmers feel that they cannot afford to spend so much of money as rental. Further, these agro machines are required only for a short period of a few weeks every year. Investing in them does not make economic sense. Thus, the farmers just burn the paddy straw.

Organic manure much needed
With a high focus on promoting organic farming by the Government of India, there is a large and unmet demand for organic manure in the country. Biomass can be converted into manure using a process called composting, a natural decomposing process where biomass such as paddy straw is broken down to micro-organisms and into a nutrient-rich compost / organic manure. The question is why organic manure is not being produced on a large scale, utilising millions of tonnes of paddy straw that is readily available. Paddy straw is adequately available and organic manure is in demand. Inadequate supply chain management to produce manure and facilitate transportation to consumers is thus clearly evident.

Huge demand for briquette as fuel
Paddy straw can be used as fuel in brick kilns, power plants, cement units and industrial boilers, by converting paddy straw into pellets / briquette. ‘Briquetting’ is the process of converting low-bulk-density agricultural material such as paddy straw into solid fuel (concentrated fuel briquette) with high density. Biomass briquette is produced from crop residue (biomass) for use as fuel. The briquette is formed in cylindrical logs using high mechanical pressure without the use of a chemical binder.  Packing paddy straw into briquette increases bulk concentration of paddy straw, transportation cost is reduced and it is easy to store and transport.

Comparison of   paddy straw as briquette fuel with fuel  from other sources

Such briquette / pellets provide much more heat and emit less than 50 per cent of particulate matter and only a fraction of ash from burning an equivalent amount of coal. The price of briquette fuel produced from paddy straw may be in the region of Rs 5800 to Rs 6500 per tonne, depending upon the regional demand supply scenario. The Ministry of New and Renewable Energy estimates about 270 million tonnes of such agricultural waste, including paddy straw, is annually available in India that can produce 28,000 MW of power. About 800 kg of paddy straw-based briquette can replace a tonne [1,000 kg] of coal. The Union Environment Ministry had announced a scheme to provide entrepreneurs inentives to manufacture briquette from paddy stubble.

The Power Ministry in October 2021 had decreed that all thermal power plants should ensure 5 per cent compliance by October 2022.  However, India has been severely lagging in ensuring that at least 5 per cent of coal used in thermal plants is mixed with biomass, despite guidelines mandating them to do so. India’s thermal power plant operators are unable to comply with norms that require them to mix coal with a certain proportion of biomass because of inadequate supply of briquette. In the period April 2020 to March 2021, only eight power plants had co-fired biomass pellets, and the number has risen to 39 now. To put that number in perspective, India has around 180 thermal power plants. Apart from power plants, paddy straw briquette can be used profitably in cement plants in kilns. Many cement units are eager to use briquette as fuel due to several advantages but unable to do so due to supply constraint of briquette. This again points to inadequate supply chain management practice.

Use of paddy straw as feedstock for bio-ethanol
The Government of India is now asking the industry to boost the production of ethanol, as the administration is targeting to increase ethanol blending with petrol to the level of 25 per cent. Several incentive measures have been announced to boost the production of ethanol. Due to supply scarcity of ethanol, the Government of India has permitted even food grains such as rice and maize to be used as feedstock for production of ethanol. To achieve the target of 20 per cent blending by 2025, about 1,016 crore litres of ethanol would be required. About 334 crore litres ethanol would be required for other usage.  It appears that availability of ethanol blending with petrol would not be adequate.

Obviously, paddy straw which is available in large quantity should be used as feedstock for the production of ethanol. IISc, Bangalore has devised a way to extract ethanol from paddy straw. It is claimed that 100 kg of paddy straw can produce 36 litres of ethanol, while wheat stalk of the same quantity can produce 53 litres. The scientists have come out with a pre-treatment process that helps hydrolysis and fermentation. Making ethanol is essentially breaking down the poly sugar content in crop residue into simple sugar and then converting it into ethanol through fermentation.  The scientists used marine cellulolytic bacteria for hydrolysis and fermentation was done with isolated yeast strain. Though some steps have been taken to produce ethanol from biomass, it is surprising that active steps have not been taken to use paddy straw for the production of ethanol.

What is the way out?
Millions of tonnes of paddy straw are available during the short period of two or three weeks, which is now largely burnt. The solutions pointed out must be implemented as quickly as possible and with efficiency. Supply chain management is the key. The concerned states – Punjab, Haryana, Uttar Pradesh – should jointly promote an organisation with the object of facilitating the collection of paddy straw and its use as manure, for use in agriculture, for conversion into briquette, for use as fuel, and for production of ethanol. Since the paddy straw is cut and removed during the short period, adequate  storage facilities are required and since it would be expensive to transport the straw over long distances, it is necessary to promote a facility to use paddy straw for the production of organic manure, briquette and ethanol proximate to the paddy farm area.

Power plants, cement and fertiliser units and chemical industries have to be encouraged to utilise paddy straw for production of manure, briquette and ethanol. Possibly, the units can be tasked with responsibility and given the authority to cut paddy straw after paying a nominal fee to the farmers. The above arrangement would be a win-win situation for paddy growers as well as user industries. And, of course, New Delhi and nearby regions would be saved the pollution horror.

(The writer is managing trustee, Nandini Voice for the Deprived. He is a chemical engineer and lives in Chennai.)