Field trials of Pusa’s stubble solution show mixed results
Deepak Yadav, a farmer in Jhuljhuli village of south-west Delhi’s Najafgarh, picks up and displays the stubble of a late variety of Basmati strewn on his two-acre farm.
Deepak Yadav, a farmer in Jhuljhuli village of south-west Delhi’s Najafgarh, picks up and displays the stubble of a late variety of Basmati strewn on his two-acre farm. It’s in the same form it was in more than a month ago when district officials sprayed the Pusa bio-decomposer on the farm, they had told him the post-harvest stubble would turn into manure in 15 to 20 days.

For some reason, the bio-decomposer doesn’t quite seem to be effective on the post-harvest stubble of the fine-grained rice.
“We had got the bio-decomposer sprayed on our field on October 23 and it has been a month and the stubble has not shown any sign of melting,” said Yadav, 33 . He quickly added: “We are not nitpicking. The Delhi government’s initiative could be a good solution for farmers cultivating mota chawal (non-basmati rice), but we have not benefitted much.”
The Pusa bio-decomposer has been developed by scientists at the Indian Agricultural Research Institute (IARI) in New Delhi to turn post-harvest crop residue into manure, and has been plugged by Delhi chief minister Arvind Kejriwal as a potential solution to the annual practice of stubble burning in neighbouring agrarian states such as Punjab, Haryana and Uttar Pradesh that covers the national capital in a blanket of smoky haze every winter.
In the capital, the bio-decomposer was sprayed free in 25 villages between October 11 and November 20. Hindustan Times visited some villages in the rural pockets of Delhi to find out how effective it had been. Some farmers found the solution to be useful in converting stubble into manure, some said that it was taking much longer than the 15-20 days the Delhi government said the process would take.
The free spraying was not done everywhere, but interested farmers could contact the district administration and get their farms sprayed if they wanted to. The government survey was limited to 2,000 acres of non-basmati fields.
In the same village where Deepak Yadav grows basmati, three farmers cultivate non-basmati varieties. Two of them said they seen noticeable results in their fields where the bio-decomposer successfully turned the sturdy stubble into manure.
“The stubble from non-basmati varieties is thicker and coarser, and when we use harvesting machines, the remains of the straw requires some kind of intervention. It took around 22 days for the stubble to turn into manure. It is good that the government is coming up with solutions for farmers and providing this free of cost,” said Kushal Singh, who owns eight acres in Najafgarh.
The early response for the decomposer may be mixed, but most farmers say the solution could be a viable option. Farmers should be told how exactly the solution works, under what circumstances it could take longer than the promised 15-to-20 days to turn stubble into manure, and what the farmers need to do to ensure the process is faster and more effective, they said.
How the solution works
The bio-decomposer is being tested in the fields of Uttar Pradesh, Haryana and Punjab and factors such as temperature and quality of stubble plays a role in the impact of solution, said Dr AK Singh, director of IARI . He said the process takes at least 25 days, but could last as long as two months.
He said that bio-decomposer works on stubble after it has been cut into small pieces by the Super Straw Management System (SMS). SMS is a machine attached to a combine harvester, which chops the stubble remains into pieces. The solution is then sprinkled over the stubble.
“Once the field is harvested, the solution has to be sprayed in the field after which the field should be plowed with a rotavator machine so that the solution is mixed with the soil. The field should then be irrigated and left for 25 days. When left for 25 days, we have seen that the effectiveness of the decomposer was as much as 90%,” Singh said.
He said that for the decomposition to be effective, a minimum 25 days is needed between paddy harvesting and sowing of the wheat crop. When the temperatures are lower or when the bio-decomposer is used after machines such as Happy Seeder are put to use, the time for decomposition was around two months, Singh said. The Happy Seeder is a machine that cuts and lifts rice straw, sows wheat, and deposits the straw over the sown area as mulch.
A senior official of the Punjab agriculture department said that in the agricultural demography of Delhi, such simple solutions could be easier, but Punjab has nearly 2.7 million hectares of land under paddy cultivation, of which 600,00 hectares is used to grow basmati varieties.
“It is great that the Delhi government is taking the initiative and wants to find a solution for the problem of stubble burning, but agrarian states such as Punjab, Haryana and even UP have been experimenting with solutions for years now, and if things were this simple, then we would be the first to implement it. We are not denying that a certain bio-decomposer could be yielding better results, but the result depends on multiple factors,” the official said, requesting anonymity.
Farmers who harvested their fields in the latter part of October or early November, when the temperatures start falling, would have possibly seen that the process takes longer, said a Delhi government spokesperson.
“I don’t know which farmers are finding it to not be effective, but it could possibly be because in lower temperature the fungal growth takes time. The field should also be irrigated, because the fungus needs that to grow. But the non-basmati farmers that we have surveyed have seen a tremendous result from the Pusa bio-decomposer,” the spokesperson said.
Delhi is different
Tribhuvan Singh, a farmer in Daryapur village of Najafgarh, said the practice of setting fire to stubble to clear the fields has been almost done away with in Delhi. He said that because of small landholdings, it is easier for farmers here to hire labour and manually get rid of the stubble.
“There are two problems. Since the fields are smaller, the use of mechanised harvesting is neither a feasible option, nor a very popular one here. Another reason is that when you harvest some fine basmati varieties by machines, the grain tends to split and this fetches lower prices in the market. So the need for such a bio-decomposer is barely there in Delhi,” said Singh.
The Delhi government had on November 5 announced the formation of a 15-member impact assessment committee to study the effectiveness of the Pusa bio-decomposer in 2,000 acres (810 hectares) of Delhi. Based on the committee’s report, Delhi environment minister Gopal Rai had written to the Commission for Air Quality Management (CAQM) in Delhi and adjoining areas, calling the bio-decomposer a “success” in Delhi and suggested that the new body direct states such as Punjab and Haryana to use the technique.
The Basmati Survey Report, 2018-2019, by the Agricultural and Processed Food Products Export Development Authority (APEDA) showed that Delhi had a total of 1.58 hectares of land under rice cultivation, out of which in 1.2 hectares basmati varieties were being grown.
Similarly, in states such as Punjab and Haryana there was a consistent shift towards the cultivation of basmati varieties, instead of non-basmati ones. The APEDA report shows that in Punjab, between 2018 and 2019, 549.19 hectares of land was under basmati cultivation, compared to the total of 2863.08 hectares under rice cultivation. In Haryana, out of 1278.79 hectares of land under rice cultivation, 631.75 hectares were under basmati.
Latest data also shows that the area under basmati this year in Punjab was the highest in five years, a 4% increase compared to last year.
“In Delhi, the practice of stubble burning is not prevalent. That is also because the city has a major packaging industry, so the stubble from paddy is sold off at a good price, without having to burn it. This was just an experiment. We need to send out the message that this is a feasible solution. Happy seeders, etc have not worked because those are not practical solutions,” the Delhi government spokesperson said.
She added, “These machines are hardly used for 20 days in the whole year. Even if all the subsidies were working perfectly and reaching the farmers in time, it is very expensive. No one will invest that much for its use for just 20 days in a year. The bio-decomposer is a great alternative.”

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