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What is Stubble Burning ?
Stubble (parali) burning is a method of removing paddy crop residues from the field to sow wheat from the last week of September to November. Stubble burning is a process of setting on fire the straw stubble, left after the harvesting of grains, like paddy, wheat, etc. It is usually required in areas that use the combined harvesting method which leaves crop residue behind.
The process of burning farm residue is one of the major causes of air pollution in parts of north India, deteriorating the air quality.
Along with vehicular emissions, it affects the Air Quality Index (AQI) in the national capital and NCR. Stubble burning by farmers in Haryana, western Uttar Pradesh and Punjab in north India is considered a major cause of air pollution in Delhi and its adjoining regions.
Paddy stubble burning is practised mainly in the Indo-Gangetic plains of Punjab, Haryana, and UP to clear the fields for rabi crop sowing. The paddy crop is harvested between the first and last weeks of October in Punjab and Haryana. Then, farmers sow the wheat crop from the first week of November until the middle of December.
The major reason behind the stubble burning is the short time available between rice harvesting and sowing of wheat as delay in sowing wheat affects the wheat crop. Between the harvesting of the paddy crop and the sowing of the next crop, there is only a two to three weeks’ time window is left.
The rice stubble burning is highest in the state of Punjab followed by Haryana, whereas Uttar Pradesh ranks higher in wheat stubble burning.
Crop residue burning is practised by the farmers to prepare the land for the next cultivation. Through this method, the remains of crops like straw which remains in the field as residue after harvesting is burned. Therefore, stubble burning is considered one of the cheapest methods to clean the field after the harvesting season.
Impact
Pollution: Stubble burning emits toxic pollutants in the atmosphere containing harmful gases like Carbon Monoxide (CO), methane (CH4), carcinogenic polycyclic aromatic hydrocarbons, volatile organic compounds (VOC). These pollutants disperse in the surroundings and eventually affect air quality and people's health by forming a thick blanket of smog.
Soil fertility: Soil becomes less fertile and its nutrients are destroyed when the husk is burned on the ground
Heat penetration: Stubble burning generates heat that penetrates into the soil, causing an increase in erosion, loss of useful microbes and moisture.