Agriculture Reference
In-Depth Information
8.2
EMISSION OF GREENHOUSE GASES
The three major GHGs are carbon dioxide, methane and nitrous oxide,
besides chlorofluorocarbons. A brief description about their sources and
sinks is given below.
8.2.1 CARBON DIOXIDE
The main sources of carbon dioxide emission are decay of organic matter,
forest fires, eruption of volcanoes, burning of fossil fuels, deforestation
and land-use changes.
8.2.2 METHANE
Methane is about 25 times more effective as a heat-trapping gas than
CO 2 . The main sources of methane are: wetlands, organic decay, termites,
natural gas and oil extraction, biomass burning, rice cultivation, cattle and
refuse landfills.
8.2.3 NITROUS OXIDE
As a greenhouse gas, nitrous oxide is 298 times more effective than CO 2 .
Forests, grasslands, oceans, soils, nitrogenous fertilizers, and burning
of biomass and fossil fuels are the major sources of nitrous oxide,
while it is removed by oxidation in the Stratosphere. Soil contributes
to the largest amount of nitrous oxide emission. The major sources are
soil cultivation, fertilizer and manure application, and burning of
organic material and fossil fuels. From an agricultural perspec-
tive, nitrous oxide emission from soil represents a loss of soil nitro-
gen, reducing the nitrogen-use efficiency.
8.3
IMPACTS OF CLIMATE CHANGE ON AGRICULTURE
Global climatic changes can affect agriculture through their direct and
indirect effects on the crops, soils; livestock and pests. An increase in at-
 
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