Pollution

CSE experts explain: Strategies to reduce crop residue burning for air pollution mitigation

Farm residue burning is a serious seasonal problem with severe public health consequences

 
By DTE Staff
Published: Friday 10 November 2023
Photo: iStock__

The Supreme Court of India has come down heavily on Punjab and Haryana for crop residue burning. The large-scale burning of crop residues from the rice–wheat systems of Punjab, Haryana and western Uttar Pradesh contributes significantly to regional air pollution. This is a serious seasonal problem with severe public health consequences in cities and rural areas of the National Capital Region of Delhi.

Here are key highlights of strategies from Delhi-based think tank Centre for Science and Environment presented in 2017 to reduce crop residue burning for air pollution mitigation.

Why are farmers burning crop residues?

Shorter cropping cycles: Multiple cropping and shortened intervals between crops give a very short window of about 10–15 days during which the field needs to be prepared for the next crop. This does not give farmers enough time to allow straw to be incorporated in the soil or use other methods of disposal. In Punjab, this interval is further shortened by the rules, which delays the sowing of paddy till after the onset of rains to minimize dependence on groundwater for irrigation. 

Increased mechanisation of harvesting: The use of mechanized harvesters leaves stubble of 10– 30 cm in the field, depending on the type of crop, which was not the case earlier with manual harvesting. It is too expensive to hire labour to clear this stubble.

Labour shortage: Use of expensive labour for stubble extraction is not feasible. Costs are especially high in Punjab and Haryana, where farm sizes are large and use of mechanized harvesters is common. Burning of residues is a cheaper and easier option.

No market for crop residue: The local economy cannot absorb straw any more for roofing of houses etc., as it did earlier. The low commercial and economic value of crop residue, coupled with the high costs of processing, reduces its value for farmers. Although the quantities of residue produced are equivalent to the total crop output, this entire volume of residue has little or no economic value. But it can be raw material for a variety of products that have not been adequately explored yet. 

Unless these factors are addressed, any external ban/fine/penalty imposed on crop residue burning will not work. 

Address barriers to promote solutions

The solution to the problem of crop residue burning is fairly well known. But there are several barriers to the implementation of these strategies. The commercial supply chain and ecosystem for alternative utilisation is currently nearly non-existent, and needs to be created and sustained through appropriate policy changes. Enforcement is also challenging due to the sheer extent of incidence of burning, which is often beyond the capacity of the existing resources. Fines, penalties and charges regularly prove ineffective, mainly due to lack of effective alternatives.

Promote agri-implements with subsidy 

The cost of agri-implements needed to reduce burning is high. As these implements are used only for two to three weeks a year, farmers do not consider these worth investing. The state government has rolled out schemes for providing subsidy for mechanical implements that can mix the crop residue with soil to improve fertility. In spite of subsidies, only a small number of farmers can access them. The subsidy amount can be augmented.

Currently, Punjab proposes to provide subsidy for 67,750 units of agricultural implements per year and Haryana has notified a scheme in May 2016 to subsidise 1,810 units of agricultural implements. This is not sufficient, considering 56–57 million tonnes and 36–37 million tonnes of crop residue are generated in Punjab and Haryana, respectively. This subsidy for agricultural equipment, which will retill the straw or bale it for use in energy and paper plants, needs to be stepped up immediately.

Recommendation on agri-implements

  • Augment subsidy and make it accessible to larger number of farmers
  • Promote co-ownership models for the agri-implements: In Punjab, there are more than 1,700 cooperative and privately run Agricultural Machinery Service Centres (AMSC), which can be supported with subsidies on purchase of agri-implements. These agencies can make such implements accessible to farmers. It is important that farmers understands the value of crop residues and use these implements for extraction and packaging. 

Utilise crop-residues fuel in biomass-based power plants 

Crop residue can be used as fuel to generate electricity through biomass-based power plants. Such plants aggregate the combustion of crop residues. The emissions from these are much easier to control and mitigate. Punjab has a plan to build biomass-based power plants of 600 MW. So far, only 62.5 MW has been commissioned and another 44 MW is in various stages of planning and implementation.

Haryana needs to formulate a policy for biomass-based power plants and set targets.

The existing power plants in Punjab are facing problems of low demand and the inability to sign longterm power purchase agreements with state governments. This is partially attributable to the power surplus situation.

Currently, operational and planned projects in Punjab would cumulatively utilise just 1.22 million

tonnes of paddy straw against an estimated 17–18 million tonnes produced. This is clearly not good enough and the government needs to step up its utilisation of straw and set up power plants expeditiously.

It may also be noted that there are some variants of high-silica content paddy that are unsuitable as fuel in power plants. Along with some other kinds of crop residue, these cannot be utilised effectively for biomass-based power generation. Further, technology innovation is needed in this regard. 

Recommendation

Prioritise biomass-based power: State governments need to incentivise establishment of biomass-based power plants through fiscal interventions and prioritization. Along with long-term purchase contracts for the power generated thus, this will effectively promote the development of a market for crop residue and build a commercial supply chain around it. Several social entrepreneurs have come forward to develop business model. But this requires enabling infrastructure and policy support. 

Use of crop residues for production of biofuels and fertilizers 

Crop residue contains high concentrations of organic nutrients, which ought to be returned to the soil in order to retain its fertility and yield potential. These can be used either in a decentralised small-scale ex-situ unit or through organized commercialization for the production of fertilizers. Similarly, they can be used to produce biofuels. 

The scale of currently operational production facilities for biofuel and biomass-based fertilizers is very small. This needs to be expanded by incentivizing startups / entrepreneurs for manufacturing and supply chain of the above technologies. Collection mechanism remains a problem. 

Recommendation:

Prioritise biofuel by mandating its use in specific sectors: The state governments, along with appropriate policy interventions from the central government need to incentivise utilisation of biofuels. For example, higher levels of biodiesel can be permitted for blending with regular diesel and made available commercially. 

utilise as raw material for biomass pellets and other uses 

Biomass pellets can be sold commercially as the main fuel for industrial boilers and replace coal. Micro-pelletization should be incentivised and its local usage promoted. There are other small-scale industries such as cardboard manufacturing and mattress production that can utilise straw. Straw can also be used for substrata for mushroom cultivation. Sugar cane residue or bagasse is used as the raw material for the production of paper. 

Recommendation:

Fiscal support to promote biomass-based products in specific sectors: State governments, along with appropriate policy interventions from the Central government, need to popularize biomass-based paper and other such products made from crop residue. This has to be supported, along with the development of markets for such products and a commercial supply chain built around it. Industry partnership is important. 

R&D and crop diversification 

In the long term, there is a need to develop a range of alternatives. For example, Punjab Agricultural University is developing a variant of paddy straw that has lower silica content, thereby making it suitable for utilisation in biomass-based power plants. Similarly, using crop variants that have a shorter maturity period allows for more time for farmers to prepare field, allowing in-situ re-assimilation of the crop residue into the soil. Such research needs to be promoted and popularized rapidly. 

There is also ongoing research into the design of mechanical harvesters, which will reduce the length of the crop residue that remains on the field, thereby ensuring reduced generation of crop residue. This needs to be speed tracked, along with being made popular. R&D efforts require intensive investments in terms of time and resources. The results will only be visible in the medium to long term and will require intensive efforts to execute. 

Recommendation: Support research projects that can work towards reducing crop residue generation  

Crop residue collection mechanism 

There is no centralized or uniform decentralised mechanism for the collection, storage and commercial sale of crop residues to support all the initiatives and enterprises that are possible around the reuse and recycling of crop residues. This makes procurement of raw material very difficult. For instance, power producing companies are dependent on specific farmers for supply of biomass fuel. There is also uncertainty of year-round availability of crop residue due to its seasonal nature, coupled with the lack of infrastructure. 

Recommendation:

Create a uniform decentralised mechanism for the collection, storage and commercial sale of crop residue. This will facilitate easy procurement of biomass fuel for power generation and other uses. The strategy, broadly, is to assign a real economic and commercial value to the agricultural residue and making burning it an economic loss to the farmer.

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