Agriculture Reference
In-Depth Information
Table 3.1
Estimated emis-
sions from global rice fields
(Tg CH
4
/yr)
Country
Irrigated
rice
Rain-fed and deep
water rice
Total
India
7.41
0
7.41
China
3.99
2.09
6.08
Bangladesh
0.47
1.19
1.66
Indonesia
1.28
0.38
1.65
Vietnam
1.26
0.39
1.65
Myanmar
0.80
0.36
1.17
Thailand
0.18
0.91
1.09
Other
2.32
0.67
2.99
Monsoon
Asian Countries
Rest of the World
1.2
0.49
1.7
Total
18.9
6.49
25.39
global emission growth rate and under all the scenarios CO
2
emission in year 2100
will be higher than the year 1990 level in the region.
Till date, the actual mechanism of N
2
O emissions is not well understood and
its emission coefficient calculated by IPCC methodology shows wide variability
(Kroeze et al.
2003
). The IPCC methodology led to over-estimation of N
2
O emis-
sions from legumes (Gregorich et al.
2005
).
The CH
4
emissions from rice paddy cultivation under alternate scenarios are
more or less stable around 4 Tg/yr. In India, there are diverse cultivation practices
in various parts of the country depending upon water availability. Continuously
flooded irrigated farming contributes to CH
4
emissions at the rate of 0.0251Gg CH
4
/
km
2
/yr while upland farming contributes very negligible amount of CH
4
emissions
(Garg et al.
2001
; Fig.
3.1
).
The major CH
4
sources in India are livestock farms, paddy fields, coal mining,
municipal solid wastes, natural gas exploration and gas flaring and biomass burning
etc. In the year 2000, CH
4
(18.63 Tg) and N
2
O (0.31 Tg) emissions contributed 27
and 7 %, respectively, to India's CO
2
equivalent Greenhouse gas (GHG) emissions
(Garg et al.
2003
). The major N
2
O emission sources include use of synthetic fertil-
izers in agricultural fields, indirect emission from atmospheric deposition of NH
3
and NOx, biological N
2
-fixation, coal combustion, oil products combustion, crop
residue burning and industrial activities, etc. However, emissions from synthetic
fertilizer use contributed the maximum percentage (67 %) among all other sources.
In the year 2003, the agriculture sector contributed about 65 % of CH
4
emissions
and above 90 % of N
2
O emissions in India (Garg et al.
2003
; Garg et al.
2002
).
Parashar et al. (
1997
) have estimated methane emission from rain-fed low land
paddy fields is about 25 t/Km
2
, while irrigated rice fields and deep water rice fields
contributed on an average 32.46 t/Km
2
and 19 t/Km
2
, respectively. The study
showed that in 1995, Greater Mumbai (0.51 Tg), Midnapore, WB (0.24 Tg), Bilas-
pur, MP (0.17 Tg), Burdwan, WB (0.16) and Raipur, MP (0.15 Tg) were the top five
districts in terms of methane emission in India. They had also analyzed sectorial
emissions in all Indian districts and showed that Midnapore (West Bengal); Cuttack
