ISLAMABAD: Modern technology must be utilised to reduce the effects of crop burning, instead of banning the practice altogether, a report by a United Nations body has suggested.

The report, Sustainable Management of Crop Residues in Bangladesh, India, Nepal, and Pakistan: Challenges and Solutions, released by the UN Economic and Social Commission for Asia and the Pacific, (UN-ESCAP), noted that residue burning plays an active role in contributing to air pollution in the Indo-Gangetic plains of South Asia.

It proposes a sub-regional framework under which interventions can assign a real economic and commercial value to crop residues, so that their burning results in an economic loss to the farmer.

“The banning of residue burning and levying of fines does not address the crux of the problems farmers face and there is a need for a combination of technologies and incentives to reduce burning,” the report says.

UN-ESCAP report says residue burning exacerbates air pollution

The UN report observed that crop residue burning increases the concentration of particulate matter and black carbon in the air, adversely affecting the health of both rural and urban populations. This burning degrades soil fertility which needs to be compensated by greater use of fertilizers and can reduce agricultural productivity in the long run. Greenhouse gases emitted from burning also contribute to global warming and climate change.

Residue burning in Pakistan

In Pakistan, the burning of combined harvested wheat straw is reported to have increased. Due to challenging management practices, limited resources of the farming community, and a short window for seeding the next crop, rice straw accounts for a substantial percentage of residue burning, the report says.

According to a survey, rice straw burning is the most common activity in Punjab province, accounting for 72 per cent of all practices. The available combine harvesters cut the standing rice crop at the height of 400-800mm and leave behind a swath of loose straw spanning a width of two meters and weighing about three to four tonnes per hectare, the report noted.

In a lodged situation, harvesting is even more difficult as it requires cutting closer to the ground level and loose straw weight increases to about five to eight tonnes per hectare, which is usually subjected to burning. It is estimated that less than five per cent of maize straw is burned. Burning sugarcane trash is a common practice in Pakistan, the report says.

During cane harvesting, cane trash is left on the surface of the fields, and cane growers mostly get rid of the trash by burning, while stubbles are uprooted. This practice is however reducing due to the imposition of penalties for burning, the report states.

Wheat and rice straws are not utilized as industrial raw materials on a large scale in Pakistan. The other uses of these residues are limited to animal bedding, garden mulch, heating fuel, ethanol production, paper making, building material, mushroom growing, fruit packing, and industrial product packaging, the report suggested.

As per estimates, 40pc of wheat straw is used for other sectors which include exports, out of which, nearly 5pc is used by the pulp and paper industry and constitutes approximately 85pc of the total cost of low-quality papers.

The burning of crop residue depletes the soil of its organic matter, and major nutrients and reduces microbial biomass in soil that ultimately impairs the efficacy of organic matter application in the next cropping season. In addition, it causes the loss of vital components such as nitrogen, phosphorus, sulfur, and potassium from the topsoil layer, making the land less fertile and unviable for agriculture in the long run, the report stated.

Initiatives by Pakistan

In Pakistan, the government has taken the initiative to install biomass energy facilities and revise renewable energy legislation. Nepra is aiming to increase the country’s power generation capacity by providing attractive incentives for the construction of new cogeneration power plants that burn garbage.

More than half of the animal dietary needs are fulfilled by crop residues, one-third by grazing, and the rest from other crops and their by-products. In local dairy sheds, animal fodder mainly comprises wheat straw which has immense nutritional value for cattle and has no close substitutes. Wheat straw constitutes about 60pc of the fodder used for meeting the dietary needs of livestock.

It is so critical that an increase in its price leads to a corresponding increase in the prices of milk and meat. In less than 20pc of situations, rice straw mixed with green fodder is utilized as animal feed when there is a shortage of wheat straw. Maize straw is also mostly consumed by cattle. Sugarcane topping is traditionally utilized as animal feed by itself or by supplementing with some additives.

Published in Dawn, June 13th, 2023