Book of Extended summaries ISDA

International Conference on Reimagining Rainfed Agro-ecosystems: Challenges &
Opportunities during 22-24, December 2022 at ICAR-CRIDA, Hyderabad
Further, in paddy fields, soil microbial activities are the main factors controlling the
production and uptake of CH4 (Conrad 1996). Methanotrophs are aerobic to microaerophilic
bacteria, that metabolize and convert methane into carbon-di-oxide by oxidizing
up to 90% of the CH4 (Krause et al., 2010; Ma et al., 2013). The root treatment of
methanotrophs is an effective option to mitigate the CH 4 emission (Dash et al., 2019). The
addition of basic slag and methanotrophs to the rice soil could reduce the CH 4 emissions by
affecting the physico-chemical and biological properties of the soil. So, in this study we
have evaluated the individual as well as combined effect of the basic slag and methanotrophs
on the methane emission in lowland rice to mitigate the GHGs emissions in rice by
application of basic slag and methanotroph formulation.
Methodology
We have conducted the field trial at the experimental farm of ICAR-NRRI, Cuttack, Odisha.
There were 8 treatments and 3 replications, and the experimental design was randomized
block designing (RBD). The gas and soil samples were collected on critical growth stage
(Panicle initiation) of rice with three replications for the estimation of GHGs emissions and
soil parameters. The GHGs (CH 4, N 2O, and CO 2) fluxes from the rice ecosystems were
estimated continuously at 5-7 days intervals by collecting the gas samples by using the
‘manual close chamber method’ (Bhattacharyya et al., 2013, 2016). The GHGs concentrations
were analyzed by using gas chromatography (Model no: Trace 1110 Gas Chromatograph; M/s
Thermo). Enzymatic activities and carbon pools were estimated in the laboratory by using
standard methods (Nayak et al., 2016).
Treatment details: (i) RDF- recommended dose of fertilizer (RDF), 80:40:40:: N: P 2O 5:K 2O
kg ha −1 ; (ii) BS- basic slag (1 t ha -1 ); (iii) BS+MTH (R)- basic slag + methanotroph (root dipbroth));
(iv) BS+MTH (F)- basic slag + methanotroph (formulation as top dressed: acaciabased
at 7 days after transplanting (DAT); (v) BS+MTH (R&F)- basic slag + methanotroph
(root dip-broth + formulation as top dressed, at 28 DAT; (vi) MTH (R)- methanotroph (root
dip-broth); (vii) MTH (F)- methanotroph (formulation as top dressed, at 7 DAT); (viii) MTH
(R&F)- methanotroph (root dip-broth + formulation as top dressed, at 28 DAT).
Results
The soil carbon pools (microbial biomass carbon, readily mineralizable carbon and KMNO 4-
C) and enzymatic activities (Dehydrogenase and fluorescein di-acetate) were highest in BS +
MTH (R&F) treatments at the panicle initiation (PI) stage in lowland rice ecology. The CH4
emission was lower in slag + methanotroph amendments than other treatments. In rice
system, the CH4 fluxes were gradually increased after transplanting and reached at the peak at
PI stage, after that gradually decreased towards harvesting period (Figure 1a). The methane
emission for the treatment BS+MTH (R&F) was lower in relative to the RDF. The seasonal
Climate resilient agriculture for risk mitigation
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