It is again the time of the year when the country’s plains are enveloped in thick smog, causing respiratory, eye, skin and other health-related issues as well as delays in and/or cancellation of flights and reduced hours for commuting by road.

Stubble burning, along with vehicular and industrial emissions, is mainly responsible for polluting the environment as the carbon dioxide released into the air combines with fog to turn it into haze and smog.

For the last couple of years, governments have been active in controlling the menace by curbing the burning of tyres at steel re-rolling mills, converting brick kilns to new zigzag technology or closing them down altogether during winters. Cases are instituted against farmers that burn stubble (of paddy at this time of the year) at their respective fields.

In just Hafizabad, one of the four districts in the famous Basmati rice-producing belt of Punjab, at least 400 paddy growers have so far been booked for violating the ban on setting ablaze crop residue.

Though it causes smog, burning straw is a low-cost solution that helps control invasive weeds and pests

But the question is, why do farmers burn the stubble even though it destroys nutrients in the soil and the heat generated by the burning leads to loss of soil moisture and useful microbes?

Kissan Board Pakistan’s vice-president Amanullah Chathha says dewdrops on standing stubble and scattered chaff in the fields make it too wet to till. The use of heavy machinery to root out the standing paddy stubble and collect the trash left in the field by the harvester is costlier and laborious.

In such a situation, burning straw is not only a low-cost solution, but the step also helps in controlling invasive weeds, particularly those resistant to herbicides and pests, he argues.

If residue burning causes loss of soil nutrients and there is the risk that repeated burning may result in a faster decline of soil organic carbon, microbes and fauna besides reducing soil’s hydraulic conductivity and aggregate stability, then retaining stubble is also no less challenging.

It may make sowing difficult by causing seeder blockages and increasing the population of mice, snails, slugs and insects. At the same time, herbicide-resistant weeds may also grow rapidly beside the eruption of stubble-borne diseases. Therefore, a comprehensive, integrated approach is required to manage stubble.

There is a need to create awareness among the farming community about the disadvantages of burning and provide alternative low-cost solutions for managing the problem.

Some opine that the government should provide subsidies to the growers enabling them to purchase machinery for mulching the crop residue and thus using it as soil nutrients. Others suggest the provision of apparatus for mixing the residue and cow dung to prepare biomass pellets as fuel for specially designed stoves. Another proposal is to use the straw for paper and cardboard manufacturing and establish a mill close to the rice-producing belt.

Hasan Khurram Hanif, a progressive grower from Sargodha, opposes offering subsidies to the farmers to purchase machinery for mulching the stubble. Rather he thinks that the solution to the crop residue issue is to create a market for the refuse.

“As a farmer, I know how difficult it is to manage rice straw. Despite the subsidy, the farmers may continue burning stubble in their fields because old habits die hard and it takes time to change attitudes.” But, if a market is created for the refuse, for example, power plants, biomass pellets, board factories etc, are set up in the area, farmers themselves will collect and sell the residue to the potential buyers.

“It’s happening in India and in a small way in Pakistan too. In Gujranwala division and Lahore, there is a demand for rice straw to the extent that the buyers are paying farmers the cost of harvesting and picking up the residue. Sadly in other areas like Sargodha, there’s no such demand.”

Dr Rizwan Yousaf, a livestock expert, recalls that crop residue would be used for animal feed and cow bedding around two decades ago. But, the concept has faded since the introduction of harvesters, which chop the rice stalks into chaff and scatter it all over the field. Burning this refuse was found to be the easiest solution. The increase in the trend, however, led to the smog problem as we see it today.

He favours preparing biomass pellets by mixing crop residue with cow dung. A private company has already marketed biomass-fueled stoves, which gasify the biomass and thus produce no or negligible smoke. While fitted with [computer] power supply fans, they also don’t need blowpipes used in the past for inflaming firewood in hearths. This tiny fan may be run on a power bank thus, there is no need for electricity, which may be unavailable in villages and outhouses.

He says that a proposal has been submitted to the Higher Education Commission for preparing a prototype of the biomass pellets preparing machine, which may be rented out like harvesters to the farmers.

About the use of the stalk as cow-bedding, he says animals like to sit on the soft bedding, but their excretion leads to the growth of fungus on the stalk. If animals consume this stalk, it causes a disease in which the ends of the hooves and tails start to fall off. Therefore, cattle farmers avoid using crop residue as cow-bedding.

Published in Dawn, The Business and Finance Weekly, October 31st, 2022