Agriculture Reference
In-Depth Information
application of N-fertilizers invariably increased the rate of N
2
O emission. Applica-
tion of nitrification inhibitors like DCD can reduce N
2
O emission up to 10-53 %
under New Delhi conditions by reducing the availability of NO
3
-(Ghosh et al.
2003
;
Pathak and Nedwell
2001
). Kumar et al. (
2000
) reported that application of DCD
with urea and (NH
4
)
2
SO
4
could reduce N
2
O-N emission by 11 and 26 % respec-
tively in irrigated transplanted rice grown on Typic Ustochrepts soil in New Delhi,
India. Malla et al. (
2005
) studied the efficacy of five different nitrification inhibitors
(neem cake, thiosulphate, coated calcium carbide, neem oil coated urea and DCD)
in Indo-Gangetic plains in rice-wheat system and reported that DCD and Ca carbide
were more efficient in reducing GWP potential than thiosulphate, neem oil, and
neem cake. Bhatia et al. (
2010
) reported that application of nitrification inhibitors
like S-benzylisothiouronium butanoate (SBT-butanoate) and S-benzylisothiouroni-
um furoate (SBT-furoate) could reduce GWP of wheat soil by 8.9-19.5 % under
both conventional and no-tillage practice. DCD, one of the most potent nitrification
inhibitors, which has been commercially used in Japan and Germany (Bharti et al.
2000
) produces non-toxic byproducts upon decomposition (Amberger
1989
). The
mitigation practices for CH
4
emission and N
2
O emission are competitive to each
other (Bronson et al.
1997
) so a balanced approach should be followed to minimize
the Cumulative Radiative-Forcing of both the gases.
Pathak and Nedwell (
2001
) have shown that application of nitrate (NO
3
-N) fer-
tilizers like calcium ammonium nitrate (CAN) in aerobic conditions and ammonium
(NH
4
-N) fertilizers like ammonium sulphate and coated urea in wetland conditions
can significantly reduce N
2
O emission. Li et al. (
2009
) reported that the time of
application of nitrification inhibitor, DCD, can increase rice yield as well as reduce
the GWP of CH
4
and N
2
O emissions from rice fields. They studied the impact of
application of DCD at three different stages of crop growth, i.e., Land preparation,
tillering, panicle initiation. They have found out that application of DCD at tillering
stage had maximum inhibitory effect on N
2
O emission (56 % reduction) while ap-
plication during panicle initiation could reduce N
2
O emission efficiently. Applica-
tion of DCD as basal reduced CH
4
emissions by 35 %.
Soils with high SOM emit more N
2
O (Bouwman et al.
2002
) and carbon and
nitrogen cycles depended on each other in the soil environment (Li et al.
2005a
).
N
2
O is released during both nitrification and de-nitrification. Nitrification inhibitors
like Nitrapyrin, DCD and DMPP could be mixed with urea for effectively reduc-
ing the N
2
O emissions (Pain et al.
1994
). No tillage system reduces CH
4
emission
from soil as any disturbance in soil environment increases decomposition rate of
soil C (West and Post
2002
) but effect of no-tillage on N
2
O emission is primarily
determined by soil and climatic conditions (Marland et al.
2001
). Studies indicated
that there is an inverse relationship between reduction of CH
4
emission and N
2
O
emission (Monteny et al.
2006
). Zoua et al. (
2007
) estimated that about 29.0 Gg
N
2
O-N is emitted during the crop growing period from the rice fields in China
which accounts for about 7-11 % of total annual emissions in China. The study also
reported that among the different water management systems practiced in China
(i.e., continuous flooding (F), flooding-midseason drainage-reflooding (F-D-F) and
flooding-midseason drainage-reflooding-moist intermittent irrigation, but without
