Straws in the wind

Delhi has registered its worst air quality in recent times. This has prompted Chief Minister Arvind Kejriwal to >call it a “gas chamber”. Pollution in different parts of the capital has touched hazardous levels with potentially serious health effects on the rich and poor alike, especially on children, the elderly and physically vulnerable people. Leaving aside the politics, the Central and Delhi governments should take urgent measures to prevent air pollution in order to stem the current impact as well as the future cost of healthcare.

Elumalai Kannan

It is often pointed out that >paddy stubble burning in neighbouring Haryana and Punjab is a major reason for affecting air quality in Delhi during the onset of winter. Stubble burning is a common practice followed by farmers in these States to prepare the field for sowing of wheat in November as there is little time left between the harvesting of paddy and sowing of wheat. Since this practice is followed every year despite some efforts by the State governments to prevent it, the problem of air quality getting affected in Delhi during October-November will recur. Therefore, it is important to diagnose and address the fundamental problems that force the farmers to burn the paddy straw on the field and not utilise it for any productive purpose. It may appear that paddy straw has no economic value for farmers in these States.

The rice-wheat rotation

Historically, rice was not a major crop grown in Punjab and Haryana. In Punjab, rice accounted for only 7.6 per cent of the total cropped area during 1970-1973, which increased to a whopping 36 per cent during 2011-13. Similarly, in Haryana, paddy area increased from 5.6 per cent to 19 per cent during the same period. Extensive development of irrigation, assured price (minimum support price) and secured market (government procurement) have induced farmers to grow paddy and expand the area of cultivation considerably over time. Consequently, farmers in this traditionally wheat-growing belt started cultivating rice and wheat in rotation year after year. Various studies have shown that the rice-wheat rotation has put land and other resources under severe strain, resulting in depletion of soil nutrients, decline in water table, build-up of pests and diseases, and micronutrient deficiency. The State governments’ initiatives to push crop diversification as a strategy to overcome these problems have not convinced farmers to break the rice-wheat rotation. Crop diversification with vegetables and fruits hit a roadblock due to marketing problems.

Being agriculturally progressive States, almost all farmers in Punjab and Haryana grow high-yield varieties of rice and wheat. According to the Ministry of Agriculture, the average rice yield was as high was four tonnes per hectare in Punjab and 3.2 tonnes in Haryana. These States have also experienced a high level of mechanisation of agricultural operations including harvesting. In fact, combine harvesters have been extensively used for harvesting of paddy and wheat due to non-availability of labour at the time of harvesting and increase in labour cost. A rough estimate based on the grain to straw ratio showed that Punjab with an average rice production of 11.1 million tonnes during 2011-13 generated about 16.6 million tonnes of paddy straw. Similarly, in Haryana, the average rice output was 1.3 lakh tonnes and it produced about 1.9 lakh tonnes of straw.

Use of machines for harvesting has serious implications for crop residue management at the farm level. The combine harvester cuts the crop well above the ground, leaving behind substantial amount of stubble on the field. The machine leaves the residues in such a state that it is difficult to collect them manually. However, the farmers found ways to collect the wheat residue (bhusa) as it is a highly valuable animal feed and is even traded across districts. Given its economic use, the farmers run a chaff combine (reaper) after combine harvesting to collect straws, cut stubbles and make into chaff for feeding to animals directly or mixed with green fodder. So the burning of wheat residue is not necessary for the farmers because of the availability of technology and its higher economic value as dry fodder. Rice straw, however, is not used as fodder as it is found to be non-palatable to animals due to its high silica content. Because of its little economic value as animal feed and other general uses, farmers are prompted to burn it on the field instead of incurring a high cost on collecting it. In fact, field studies show that even though farmers are aware that the burning of straw is harmful to health, they do not have alternatives for utilising them effectively. Therefore, blaming only the farmers may not solve the problem of air pollution and there is a need to find sustainable technological solutions that can help farmers and simultaneously allow everyone to breathe clean air.

Looking through the haze

Biomass provides safe and reliable energy. The available paddy straw can be effectively used for power generation, which will go a long way towards overcoming the problem of disposal of crop residues and power deficit in the region. According to data from the Ministry of New and Renewable Energy, Punjab and Haryana have not made much progress in creating biomass-based power generation plants as compared to States such as Maharashtra, Uttar Pradesh, Karnataka and Tamil Nadu. Thus, there is great potential for making investments in paddy straw-based power plants which can help avoid stubble burning to a large extent and also create employment opportunities.

Incorporation of crop residues in the soil can improve soil moisture and help activate the growth of soil microorganisms for better plant growth. However, suitable machinery for collection, chopping and in situ incorporation of straw is required. Further, initiatives can also be made to convert the removed residues into enriched organic manure through composting.

Presently, a limited quantity of paddy straw is used for cardboard making and in packing industries and paper mills. However, new opportunities for industrial use — such as extraction of yeast protein — can be explored through scientific research.

There is also a need to develop rice varieties that are both rich in grain yield and high in straw quality. Use of such dual-purpose rice varieties will help to maintain food security, farm income and improve environmental sustainability.

Elumalai Kannan is Associate Professor at Centre for the Study of Regional Development, JNU, New Delhi.

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Printable version | Sep 14, 2021 1:34:23 AM |

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