50 million
people have been exposed to high levels of toxic smoke for a week so far in and
near Lahore, Pakistan as a result of burning crop waste. This is not unusual
this time of year in that part of the world. New Delhi, India and Dhaka, Bangladesh
are other large cities exposed regularly, in addition to the many small cities
exposed. November and December are typically the months when crop waste is
burned. In this area during this season, it is mainly rice straw that is burned. It is also known as the season of air pollution as this smoke from crop burning combines with construction dust, exhaust pollutants, and the firecrackers, candles, and oil lamps from Diwali celebrations.
Burning crop
waste has long been a part of traditional farming practices. Usually, the
farmers burn to get rid of the left-over rice stubble and prepare for the
winter wheat crop. India usually issues bans against burning as they have this
year, but they are often not heeded or well enforced. Transport and construction
are shut down as are schools, offices, parks, and malls. Northern India and
Pakistan are the most affected by this smog that occurs when increased smoke hits
cooler air that holds the smoke low and keeps it from rising.
India is the
world’s second-largest agricultural economy and produces crops year-round. The
92 million metric tons of crop waste burned each year contribute very significantly
to local pollution and to global warming as well. Are there feasible
alternatives to burning? There are certainly alternatives but are they feasible?
India’s farmers don’t have the capital to invest in many of the viable
solutions such as composting, biochar production, making biofuels, and improved
mechanical processing. The Indian government has initiated several programs to
address the issue, but these will take time. Meanwhile, there are estimates that
every single one of the 1.4 billion people in India is routinely exposed to
pollution levels over World Health Organization safe limits.
Source: Crop Residue Burning in India: Potential Solutions. Kawaljeet Kaur and Preetpal Singh. Agricultural Waste - New Insights [Working Title]. Dr. Fiaz Ahmad and Prof. Muhammad Sultan. October 25, 2022. Crop Residue Burning in India: Potential Solutions | IntechOpen
The crop waste
includes stalks and stems, leaves, and seed pods. Lignin is the component
prevalent in stalks and stems that is most resistant to biological and chemical
decomposition by fermentation. It is also the most carbon-rich component. The
majority of this left-over lignocellulosic biomass is made up of the
four most important agricultural crops farmed worldwide: sugarcane, wheat,
rice, and maize. In cellulosic biofuel production, the lignin is treated with special
microbes able to break it down. One possible solution is treating more of this waste
with microbes able to break it down with the added benefit of improving soil quality.
However, the farmers need to make way for the next crop so this may not be a
timely enough process for them.
Burning crop
waste has multiple negative environmental effects. These include a high degree
of air pollution and subsequent health effects, release of greenhouse gases,
biodiversity loss, and soil fertility loss. According to the 2022 book: Agricultural
Waste - New Insights:
“Burning crop residue dramatically raises air
pollution levels of CO2, CO, NH3, NOX, SOX, non-methane hydrocarbon (NMHC),
volatile organic compounds (VOCs), semivolatile organic compounds (SVOCs), and
particulate matter (PM). In essence, this explains why organic carbon,
nitrogen, and other nutrients that would normally have been kept in the soil
have been lost.”
Burning crop waste is by far the largest source of PM2.5 particulates
in the New Delhi area. The particulates travel and land on Himalayan snow,
blackening it so that the glaciers there melt faster. The situation is dubbed
unsustainable. Thus, sustainable solutions are needed.
Rice is the
most burned crop residue followed by wheat and sugarcane.
Another issue
with the soot in burning crop waste is poor visibility for drivers as the
ground-level ozone smog hangs in the air. This was exemplified recently in
Southern Louisiana where swamp fires mixed with naturally occurring fog to
cause massive traffic accidents, one involving 160 vehicles.
What Are the Potential Solutions?
Potential solutions
include composting, biochar, making biofuels, in-situ management with
mechanical intensification, and the practice of conservation agriculture that
focuses on soil health. Unfortunately, none of these potential solutions are
cheap or easy to implement on a large scale. They are all effective solutions
but require more work, equipment, time, and man-hours than simply burning away
the waste. In-situ management with mechanical intensification in the context of
conservation agriculture is done extensively in North America as a part of the no-till
farming that makes up 40% of North American agriculture. India has plans to do
this more. The method is akin to mulching and improves soil health, drainage,
and moisture retention. There are, however, some downsides to conservation
agriculture including requirements for more care in planting seeds, placing
fertilizer and manure, and assimilating the waste. More equipment may be
needed. In the case of the rice-wheat system used in India and Pakistan, there is
also the problem of weed control and targeting herbicides ideally without overdosing
and proper timing and placement of fertilizers so as to reduce runoff of both
fertilizer and pesticides. Indian and Pakistani farmers have been reluctant to
move away from traditional practices and are in need of more hassle-free and
low-cost methods and machinery to help them.
Wastes can be composted
by using them for animal bedding and layering them into dung pits. Waste can be
composted with manure into biogas (55% methane and 45% CO2) with the residue
being used as a quality fertilizer. It may be pyrolized, burned in very low
oxygen conditions, to make biochar, which is a very good long-term fertilizer
and soil conditioner. Other possible solutions include using the waste for packaging
materials, animal feed, beverage production, rural roofing, mushroom
cultivation, and wood and paper pulp.
In India and
Pakistan there is also a cultural factor in that many farmers take pride in
having cleared and well-kept-looking fields, with burning wastes being a big
part of that clearing. Fields are often tilled to be level as well. It is perhaps
akin to the pride people in modern countries take in raking leaves in their
lawns in the autumn. Thus, it is likely that much of the persistence of the practice
of crop waste burning is socioeconomic.
One thing the
Indian Ministry of Agriculture recommends is modifying farm equipment to better
process crop wastes during the normal course of harvesting:
“Create and encourage the use of suitable crop
machinery in agricultural techniques, such as the modification of grain
recovery equipment (harvesters with twin cutters to cut the straw). Offer
discounts and incentives to encourage the purchase of mechanical sowing
equipment such as baling, shredding, and turbo seeders.”
Other potentially helpful equipment promoted by the
Indian government includes rotavators, happy seeders, zero–till-drills and
straw reapers. Regular combine harvesters, which have increased in deployment
in recent years, harvest grain but discard the straw, which helps the farmers
but adds to the leftover waste.
The Indian government,
with help from the UN’s Food and Agriculture Organization (FAO), has
implemented a program to collect, transport, and store waste rice straw to be
used for other purposes. The goal is to develop a functional supply chain for
the material. One use is to make briquettes and pellets from the material which
can be burned in coal-fired plants. Biogas and ethanol production are other potential
uses. The UN thinks that up to 30% of the otherwise burnt waste can be
transformed.
Those who have
campaigned relentlessly for Indian farmers to return to traditional practices
and avoid anything involving the biotech and aggrotech companies like the scientist/activist
Vandana Shiva are helping to perpetuate practices like this and the subsequent environmental
and health effects. The farmers would also benefit much from government
subsidization of efforts to apply these technologically readily available but
economically challenging solutions. Clearly, the problem can be reduced.
References:
This
megacity is the latest to shut down as pollution chokes swathes of South Asia. Rhea
Mogul. CNN. November 9, 2023. This
megacity is the latest to shut down as pollution chokes swathes of South Asia
(msn.com)
Fuel
not fire: from burning crop waste to bioenergy. Food and Agriculture
Organization of the United Nations. July 9, 2020. Fuel not fire:
from burning crop waste to bioenergy | FAO Stories | Food
and Agriculture Organization of the United Nations
Crop
Residue Management in India: Stubble Burning vs. Other Utilizations including
Bioenergy. Gaurav Kumar Porichha, Yulin Hu, Kasanneni Tirumala Venkateswara Rao,
and Chunbao Charles Xu. Energies 2021, 14(14), 4281. July 15, 2021. Energies | Free Full-Text
| Crop Residue Management in India: Stubble Burning vs. Other Utilizations
including Bioenergy (mdpi.com)
Pollution
Caused by Agricultural Waste Burning and Possible Alternate Uses of Crop
Stubble: A Case Study of Punjab. Parmod Kumar & Laxmi Joshi. First Online:
01 January 2013. Knowledge Systems of Societies for Adaptation and Mitigation of Impacts
of Climate Change pp 367–385. Pollution
Caused by Agricultural Waste Burning and Possible Alternate Uses of Crop
Stubble: A Case Study of Punjab | SpringerLink
Crop
Residue Burning in India: Potential Solutions. Kawaljeet Kaur and Preetpal
Singh. Agricultural Waste - New Insights [Working Title]. Dr. Fiaz Ahmad and
Prof. Muhammad Sultan. October 25, 2022. Crop Residue Burning in
India: Potential Solutions | IntechOpen
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