Agriculture Reference
In-Depth Information
along with a midseason drainage system practice can reduce CH
4
emissions by
50 %. Ahmad et al. (
2009
) reported that DSR plus no tillage is a promising option
for reducing GWP of rice soil.
7.5 Fertilizer Management
Rath et al. (
1999
) studied methane emissions for same cultivar 'Gayatri' under rain-
fed lowland and irrigated condition using different fertilizer management practices
(Prilled urea, prilled urea + nimin, Urea super granule and control). They reported
that application of nitrification inhibitor, nimin with urea, reduced CH
4
emissions
effectively by inhibiting the autotrophic oxidation as earlier reported by Sahrawat
and Parmar (
1975
). Urea super-granule application at the base of the plant is also
an efficient option for reducing emission. Bronson et al. (
1991
) reported that wax
coated Calcium carbide can reduce CH
4
emission by releasing acetylene that acts as
inhibitor of methanogenesis. Application of muriate of potash reduces active reduc-
ing sunstances, Fe
2 +
content and redox potential whereby apart from increasing the
grain harvest, it also reduces methane emissions significantly (Babu et al.
2006
).
7.6 Silicate Fertilization
Ali et al. (
2008
) studied the influence of silicate iron slag on rice (
Oryza sativa, cv.
Dongjinbyeo
) in Agronomy Farm, Gyeongsang National University, South Korea.
Their study showed that silicate fertilization @ 4 Mg/ha could reduce CH
4
emis-
sions by 16-20 % and at the same time increasing the yield by 13-18 %. The growth
of the rice plant was enhanced due to increased availability of nutrients. CH
4
emis-
sion was limited due to higher concentration of ferric oxides which acted both as
oxidizing agent and electron acceptor (Ali et al.
2008
). They have reported a strong
negative correlation between CH
4
flux and free iron and active iron concentration
in soil. Other studies on silicate fertilization indicated that iron oxide suppresses
production of organic acid by acting as electron acceptor (Asami and Takai
1970
;
Watanabe and Kimura
1999
). Ali et al. (
2009
) studied the influence of silicate fer-
tilization on methane production under conventional and no-tillage conditions in
Korean paddy fields. Their study showed that methane emission was reduced under
conventional and no-tillage conditions by 54 and 36 % with silicate slag application
@ 4 Mg/ha
−1
. Silicate fertilization also reported to improve soil porosity and redox
potential, active tillering rate, root volume and leaf photosynthetic rate. Nouchi
(
1994
) and Aulakh et al. (
2000
) reported that CH
4
emissions get reduced drasti-
cally at grain maturation stage due to reduced gas conductivity as well as reduced
photosynthetic activity.
