[Commentary] A microbial spray could be the game changer against crop residue burning

Pusa Decomposer, a microbial spray, developed by the Microbiology Division of the Indian Agriculture Research Institute (IARI), Delhi, is the harbinger of hope for an end to paddy residue burning which has been on the rise in the paddy fields of Punjab, Haryana, Uttar Pradesh and around Delhi for the last half a decade. The intervention derives its name from the Pusa campus of the IARI in Delhi.

With farmers setting agricultural fields on fire from October to December to get them ready for wheat sowing after harvesting paddy, the air over the National Capital Region has been turning increasingly toxic. The pollution also spreads across the Indo-Gangetic Plains and other parts of north India.

With mounting reports of asthma and lung ailments, the Supreme Court of India and the National Green Tribunal came down heavily on the state governments concerned, accusing them of endangering people’s right to life enshrined in the Constitution. This spurred a frenzied burst of activity that ranged from providing a range of expensive farm machines to deal with the crop residue; crop diversification from the popular paddy/wheat cycle to growing maize, cotton and Basmati; and making bundles or bales of the paddy straw and taking it out of the fields. Once the crop residue is taken out it can be used for generating power, biogas, biofuel and cardboard.

Read more: Smoke from stubble burning in Punjab may aggravate COVID-19 symptoms

Carrot and stick

A carrot-and-stick approach was used to contain crop burning. Incentives were given to farmers and the machines were provided to individual farmers as well as farmer groups at a subsidised rate. For the marginal farmers, they were to be provided free of cost. Those who did not fall in line were fined, arrested and red marks entered in their property papers, ensuring they will not be entitled to government loans and benefits.

Despite the inducements and the stick, crop residue fires continued and even increased in some villages where the machines had not reached. There were also villages totally free from farm fires.

The COVID-19 pandemic and the lockdown saw nature bursting into its own – clearer skies, purer air and reports of wildlife on city roads. The opening up after the pandemic saw the magic of nature fading out. Traffic, construction activity and industry surged. From October, the first reports began appearing on the falling quality of the air of the National Capital Region. The PAU Vice Chancellor, B.S. Dhillon, said new varieties of rice had been developed that can be harvested in 93 to 117 days. These probably were one of the reasons for the farm fires that began late September this year.

In the first week of October there were 606 farm fires in Punjab and 137 in Haryana, which was nine and three times respectively higher than for the same period last year.  By October 27, the number of fires reported from the two states was 2400.  Panic buttons were pushed as hope for a healthier winter faded.

Microbe-based Pusa Decomposer

The announcement of a wild card entry for crop residue management in the form of the microbe based capsules called Pusa Decomposer by the Chief Minister of Delhi at the end of this September was like the proverbial breath of fresh air that the NCR was waiting for. An elated K. Annapurna, head of the Microbiology Division of the Indian Agricultural Research Institute (IARI), said that her team had visited the fields of farmer Prakash Singh of Hiranki village, Najafgarh block, Delhi, where the microbial decomposer had been sprayed by Chief Minister Arvind Kejriwal on October 13. Just 15 days later, on October 28, they found that 90 percent of the paddy residue had decomposed. The farmer was ecstatic and was hoping to sow wheat in the first week of November.

The search for a solution to the crop fires of the northern states goes back to 2009-2010 when paddy cultivation was shifted from May to July to coincide with the monsoon because the extensive use of water for irrigating paddy was fast depleting the groundwater. There was an explosion of farm fires as farmers opted for the quickest way to clear their fields for the winter sowing of wheat. Apart from providing a slew of subsidised machines to help farmers’ clear fields without burning paddy straw, the government of Punjab announced a USD 1 million award for technology for in situ crop residue management.

The IARI and Punjab Agriculture University (PAU) in Ludhiana have been working on the microbial spray for some years now. PAU has been working on reducing the period for decomposing the paddy straw from 40 days to 20 days if not less and is also on the brink of a breakthrough.  It seems to have been beaten in the race by the IARI.

Annapurna said that the IARI’s work was given the extra nudge with the seeding money provided by the Niti Aayog project for mass production of manure/fertiliser from agricultural biomass in 2019. The IARI solution that comes in the form of four capsules, each costing Rs 5 or Rs 20 for a packet of four capsules is so cheap and decomposes stubble so fast that it can be used by all farmers without worrying about costs or depriving the soil of its nutrients through burning.

Just four capsules are needed to convert a hectare of farm waste into useful compost says Livleen Shukla, principal scientist of the Microbiology Division in Pusa. The total cost per acre works out to about Rs 300 and includes the cost of making the concoction with jaggery, gram, blending the capsules in large containers of water and the cost of labour for spraying. While decomposing the farm waste, the fields retain some moisture and the soil is enriched, reducing the use of fertilizers. The farm fires were killing the friendly insects and worms and reducing the fertility of the fields, Shukla pointed out. Another virtue of the capsule that contains crop friendly fungi is it has no side effects.

Shukla explains how the spray is made by boiling 150 grams of jaggery or gur in water and removing the dirt. After the jaggery solution cools it is mixed in water. Then 50 grams of gram flour and the four capsules are also blended into the solution and the container is kept in a warm place for five days. The layer that solidifies on the water surface has to be blended in. A 25 litre solution, enriched by enzymes that decompose stubble, is enough for a hectare.

Annapurna says the Pusa Decomposer has to be used quickly after preparation. Timing is important. The temperature outside has to be about 30 degrees Celsius during spraying. The licence for the Pusa Decomposer has been given to eight companies dealing with bio-products.

This year, the Delhi government announced that the spray would be used on 800 hectares of farmland around Delhi. Then, Environment Minister Prakash Javadekar announced that it will also be used on 100 hectares of land in Punjab and Haryana and 10,000 hectares in U.P.

Trial this year and up-scaling in 2021

As a follow up of the microbial spray in fields this October, IARI will be assessing the quality of soils every 15 days. Simultaneously, in the IARI fields studies are being conducted to see if there will be release of methane and other gases.

“We want to bring out a holistic report on the microbe-based spray that has been developed”, says Annapurna.  Some 200 pouches of the new technology of four capsules per pouch have been sent to the agriculture department of Punjab for trial on 200 hectares. One pouch can decompose five to six tonnes of paddy straw on a hectare. The spray is dispensed just like any pesticide by individual farmers. It can also be mounted and sprayed from tractors.

This has been a trial year for the Pusa Decomposer. Next year it can be up-scaled and used on larger tracts of paddy fields provided the state governments, farmers, farmers unions and the marketing companies come together. There will have to be policy changes, extensive communication on the newest technology on offer.

This could well be the reprieve for the farmers of north India who are too happy with the dividends of the paddy/wheat cycle to switch to alternate crops.

Banner image: Containers with microbial spray solution at an IARI facility. Photo by special arrangement.