Delhi's Toxic Air: Why It’s Best To Retain Paddy Straw In Fields, Grow Short-Duration Rice

Officials talking at cross purposes have fouled up solutions to the burning of paddy stubble and loose straw by offering farmers multiple options and confusing them. Letting paddy crop waste remain in fields to decompose by itself over time and sowing of wheat in the unploughed fields has been shown to be best for retention of soil moisture, improvement of soil fertility through enhancement of organic carbon, reduction of tractor emissions, and avoidance of the release of smoke and soot. But officials and some machinery manufacturers tout removal of paddy waste from fields for production of paper, cardboard, power, ethanol and biogas as better options.

A study published in Science in late 2019 compared 10 land preparation and sowing methods in northern India’s rice-wheat cropping systems and concluded that sowing wheat directly in unploughed fields with shredded paddy straw was the best option and raised farmers profits through higher yields, and savings in labour, fuel and machinery costs. At a press conference that year Trilochan Mohapatra, then the Director-General of the India Council of Agricultural Research, endorsed the cultivation practice for its benefits for the environment and lauded the institute for pushing it.

The study said the 23 million tonne of paddy straw produced by three north Indian states if raked and baled into 20-kg, 38-cm-high bales and stacked on top of each other, would reach a height of 430,000 km or 1.1 times the distance to the moon.

Sowing wheat in unploughed fields after paddy harvest requires the harvester to be equipped with a straw shredder and spreader. The wheat seed is sown with a drill called the Happy Seeder. Over the years, enough numbers of these machines have been made available to Punjab farmers with generous subsidies. Those who don’t own them can hire them. Punjab Agricultural University had also developed the Super Seeder, which ploughs the straw into the soil.

Yet, Punjab’s Attorney General told the Supreme Court earlier this week that farmers were not adhering to alternatives to straw burning because they cannot afford the “costly” machines. He wanted them to be supplied free with the Punjab, Delhi and Central governments sharing the cost.

Among the costly pieces of equipment is the combine harvester. But farmers don’t need to own them. These are available readily on hire. The Happy Seeder costs about Rs 1 lakh. The Super Seeder is more expensive. They need high-horsepower tractors to power them. Even these are available on rent. Perhaps he also had rakers and balers in mind.

I have met scores of farmers in Punjab and Haryana who had practiced  zero tillage or low tillage conservation agriculture and are quite satisfied. Some have been at it for more than two decades.

Those farmers who are hesitant about sowing wheat amid paddy stubble can incorporate the straw using a mould-board plough which turns the soil 12-inches deep, compared to 4-inch turns done by conventional ploughs. Virender Latther, former principal scientist of Indian Agricultural Research Institute recommends sowing short duration varieties like PR-126 which mature in 110-120 days compared to the 150-160 days that Pusa 44 takes. Pusa 44 has a high yield of 10 tonnes per hectare but it also consumes more water. Latther says Haryana has banned the cultivation of Pusa 44. Punjab is said to be contemplating a ban from next year. Pusa 44 is grown on about a quarter of Punjab’s rice area (which is about 30 lakh hectares).

Latther says the best option is for Punjab farmers to plant short duration rice under the direct seeding method from May 20 before the onset of monsoon. The procurement should end by Oct. 15 (and not continue till Nov. 10 or 15). That will compel farmers to end their harvesting operations early and give them enough time to manage paddy straw and stubble by incorporating them in soil, without having to burn them. He says direct seeding of rice should be legally mandated and farmers should be given about Rs 5,000 an acre to follow the practice. This will save both water and fuel and avert smoke and soot.

But the government needs to stay on the message instead of talking in multiple voices.

The oil marketing companies, for instance, have set up distilleries to produce ethanol from paddy straw though it is not clear whether the output can compete with alcohol produced from molasses, sugarcane juice, maize and damaged rice without subsidy.

In an interview to BQ Prime in April,  NITI Aayog Member Ramesh Chand said paddy stubble was best used to produce not alcohol but compressed biogas. He said it would mesh with the cattle economy – and the ruling party’s ideology that is opposed to the slaughter of cattle – because the decomposition of straw in anaerobic digesters would be speeded up if mixed 20 percent with cattle dung. When asked whether the removal and transport of straw from large areas would not result in more emissions (from rakers, balers and trucks), he said not in places where rice was intensively cultivated. He said he had got a study done by the Food and Agriculture Organisation which showed that the biogas would not need subsidy if produced in areas where rice was densely grown.

During the Supreme Court hearing some petitioners blamed the Punjab Preservation of Sub-Soil Water Act of 2009 for late paddy sowing and late harvest leaving farmers with a short time to sow wheat, compelling them to deal with paddy straw in the quickest and lowest cost manner – by setting it on fire.

But in a note in 2018 called “Clearing the Smog on Paddy Transplanting Date,” PAU had cautioned against allowing farmers to grow rice before the onset of monsoon, as it would result in overdrawing of groundwater.

“Our worry is that these influential voices (who blame late transplanting) can seriously set back the groups attempting to address these (crop residue management) issues through technology development and dissemination,” PAU noted.  Those who cite late transplanting for stubble-burning fail to note that the share of short-duration varieties in Punjab’s rice area has increased from 32.6 percent in 2012 to 81.7 percent in 2018, it said. Among those influential voices was that of the late M.S Swaminathan, who is regarded as the architect of India’s Green Revolution.

Baldev Singh Dhillon, then Vice-chancellor of Punjab Agricultural University told me that he would not mind “ex-situ management” of rice crop residue “for the time being but ultimately it must be managed in-situ” to nourish the soil depleted by the extraction of so much grain.

If in-situ management of straw is the best option, the message should be amplified not diluted.

Vivian Fernandes is a journalist with more than three decades of practice.

The views expressed here are those of the author and do not necessarily represent the views of BQ Prime or its editorial team.