Stubble burning is intentionally setting fire to the straw stubble that remains after grains, like paddy, wheat, etc., have been harvested. The practice was widespread until the 1990s, when governments increasingly restricted its use.
Effects
The burning of stubble, contrasted with alternatives such as ploughing the stubble back into the ground or collecting it for industrial uses, has a number of consequences and effects on the environment.
Generally helpful effects
Kills slugs and other pests.
Can reduce nitrogen tie-up
Generally harmful effects
Loss of nutrients
Pollution from smoke
Damage to electrical and electronic equipment from floating threads of conducting waste
Stubble burning has been effectively prohibited since 1993 in England and Wales. A perceived increase in blackgrass, and particularly herbicide resistant blackgrass, has led to a campaign by some arable farmers for its return.
In Australia stubble burning is "not the preferred option for the majority of farmers" but is permitted and recommended in some circumstances. Farmers are advised to rake and burn windrows, and leave a fire break of 3 metres around any burn off.
In the United States, fires are fairly common in mid-western states, but some states such as Oregon and Idaho regulate the practice.
In China, there is a government ban on stubble burning; however the practice remains fairly common.
In northern India, despite a ban by the PunjabPollution Control Board, stubble burning is still practiced. Authorities are starting to enforce this ban more proactively.
Stubble burning is allowed by permit in some Canadian provinces, including Manitoba where 5% of farmers were estimated to do it in 2007.
Stubble burning in India
Stubble burning in Punjab and Haryana in northwest India has been cited as a major cause of air pollution in Delhi. Consequently, the government is considering implementation of the 1,600 km long and 5 km wide Great Green Wall of Aravalli. In late September and October each year, farmers mainly in Punjab and Haryana burn an estimated 35 million tons of crop waste from their paddy fields after harvesting as a low-cost straw-disposal practice to reduce the turnaround time between harvesting and sowing for the second crop. Smoke from this burning produces a cloud of particulates visible from space and has produced a what has been described as a "toxic cloud" in New Delhi, resulting in declarations of an air-pollution emergency. For this, the NGT instituted a fine of Rs. 2,00,000 on the Delhi Government for failing to file an action plan providing incentives and infrastructural assistance to farmers to stop them from burning crop residue to prevent air pollution. Although harvesters such as the Indian-manufactured "Happy Seeder" that shred the crop residues into small pieces and uniformly spread them across the field are available as an alternative to burning the crops, some farmers complain that the cost of these machines is prohibitive compared to burning the fields.
