Emissions of Air Pollutants from Burning of Rice and Wheat Crop Residues
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Date
2015
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CENTRE FOR ENVIRONMENT SCIENCE AND CLIMATE RESILIENT AGRICULTURE INDIAN AGRICULTURAL RESEARCH INSTITUTE NEW DELHI –
Abstract
India is an agriculture based country and produces a large amount of agricultural
residues. Farmers growing rice and wheat in rotation in the Indo Gangetic Plains and
wheat in central India use combine for harvesting their crops, which generates huge
amount of residue in the field. Due to unavailability of proper management techniques,
high cost of disposal, labour shortage, and reduced number of livestock’s per farm
family, farmers prefer burning of these valuable resources. Burning of crop residue leads
to the emission of various toxic gases, greenhouse gases and particulate matter in the
atmosphere. Therefore the present study was conducted to quantify the emission of
gaseous air pollutants and particulate matter from burning of rice and wheat crop
residues.
A field survey was conducted to assess the methods used by farmers for
harvesting of wheat (Hamirpur, Jalaun in Uttar Pradesh and Tikamgarh, Chhatarpur in
Madhya Pradesh) and rice (Karnal, Kurukshetra in Haryana), amount of crop residues
left in the field after harvesting and mode of crop residue disposal. Approximately 42-
76% farmers used combines for harvesting, whereas 24-58% harvested manually. The
use of combine was maximum in state of Haryana and minimum in M.P. The amount of
wheat crop residues generated in the field was 5 to 6 t ha-1 in districts of UP and MP,
whereas 7 to 8 t ha-1 in districts of Haryana. Approximately 8 to 9 t ha-1 of rice residue
was generated in the districts of Haryana. About 60 to 74% of rice residue and 65 to
91% of wheat residues was burned in the fields after combine harvesting. However, 70
to 75 % residues are used as fodder after manual harvesting. Average concentration of
CO2, CH4, N2O, CO, NO, NH3, SO2 and TVOC was 680 ppmv, 4.22 ppm, 443 ppbv,
106 ppmv, 35.6 ppbv, 8.3 ppmv, 3.4 ppbv and 16.4 ppmv, respectively due to burning
of rice crop residues and 752 ppmv, 3.95 ppmv, 429 ppbv 110 ppmv, 40.47ppbv, 9.3
ppmv, 4.81ppbv, and 28.6 ppmv, respectively during wheat crop residue burning. The
combustion efficiency ranged from 82.02 to 84.85%. The concentration of PM2.5 and
PM10 was 401.9 µgm-3and 527.5 µgm-3 due to rice residue burning and 342.9 µgm-3 and
78
471.84 µgm-3 due to wheat crop residue burning. Organic carbon constituted the major
fraction of PM2.5. The SEM images of rice PM2.5 showed the abundance of soot
particles, carbon particles and silica. Whereas, wheat PM2.5 showed more soot and
carbon particles. Major elements in particulate matter of rice and wheat crop residues
were carbon, oxygen and silica which contributed 78.44% in rice and 84.66% in wheat.
The X-Ray Diffraction of rice and wheat straw ash indicated the presence of silica,
potassium chloride, and potassium calcium phosphate. The study revealed that burning
of crop residues deteriorated the air quality, which can have negative impacts on
environment and human health
Description
t-9296
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