Agriculture as a Source of GHGs - Climate Resilient Agriculture for Ensuring Food Security - page 28

Fig. 3.2 GHG emissions in the agricultural sector (N 2 O from soil management 38 %, CH 4 from enteric fermentation
32 %, biomass burning 12 %, rice production 11 %, manure management 7 %) (IPCC 2007 ; Smith et al. 2007 )

fertilizers, and of methane (CH 4 ), accounting for
47 % of total emissions, essentially from live-
stock and rice cultivation.
As agricultural production is projected to
increase in developing countries, so are agricul-
tural emissions. IPCC estimates that N 2 O emis-
sions will increase by 35-60 % by 2030 and CH 4
by 60 % (IPCC 2007 ). The IPCC also projects
additional land being converted to agriculture.
Major agricultural activities which contribute
to elevated GHG emissions include:
￿ Agricultural soil management covers a broad
array of practices including fertilization with
synthetic fertilizer and animal manures;
manure deposition by grazing animals, soil
cultivation; production on N fi xing crops and
forages; irrigation; and other practices. The
category covers GHG emissions from both
cropland and grasslands.
￿ Enteric fermentation is primarily CH 4 pro-
duced by the digestive processes of agricul-
tural animals which are emitted from the
animals as gas.
￿ Manure management emissions are CH 4 and
N 2 O released from manure during storage and
handling.

￿ Rice cultivation done under anaerobic
conditions in fl ooded fi elds results in CH 4
emissions.
￿ Field burning of agricultural residues results
mostly in CO 2 emissions, which are not
counted because it is assumed that CO 2 will be
reabsorbed by plants in the next growing sea-
son. Field burning, however, also results in
release of CH 4 , N 2 O, and other minor GHGs.
Agriculture accounts for roughly 14 % of the
total global GHG emissions or about 6.8 Gt of
CO 2 e/year (Fig. 3.2 ) (IPCC 2007 ). In the period
since 1990, total provincial GHG emissions have
risen, while agricultural GHG emissions have
remained essentially constant. Within agricul-
ture, the main sources responsible for GHG emis-
sions are ruminant livestock belching and
manure, both of which release CH 4 into the air,
and release of N 2 O from soils as a result of appli-
cation of synthetic nitrogen fertilizers and
manure. In addition, there are indirect GHG
emissions from agricultural activities, such as the
CO 2 emitted during fossil fuel combustion by
farm machinery and the manufacture of fertiliz-
ers and farm machinery. These types of emissions
are typically reported by the transportation and