74
S. Ambreetha et al.
archaea on rice straw incorporation and rapid reduction in their count on addition of
nitrate based fertilizer [4]. In a crisp, CH 4 emission from paddy straw decomposition can be regulated through supplementing optimum dose of N fertilizer, thereby
suppressing global warming. In our studies, methanogenic archaea were inhibited
under flooded rice soils, owing to competition for H 2 with iron and sulphate reducers
and denitrifiers, however, addition of inorganic fertilizers acted as sources of electron donors thus improving the methanogenic flora and methane production [73].
While the methane oxidizers in oxic-anoxic interface, uptakes methane escaped from
anaerobic degradation of organic matter [12].
In north-eastern states of India, the paddy residues are burned resulting in waste
of essential nutrients apart from causing environmental pollution [62]. In such cases,
it is mandatory to create awareness and incline the farmers towards conversion agriculture and make the best N supplement out of paddy straw. Additionally, returning
paddy straw to the field creates huge shift in paddy-associated anaerobic microbiome by decreasing denitrifiers and encouraging the population of iron reducers
[100]. Paddy straw decomposition is rapidly carried out by hydrogenotrophic and
acetoclastic methanogenesis involving diversified bacteria and archaea of various
phyla [103]. Reconstruction of paddy associated soil microbial community is also
achieved by regular rotation with green manures. Long term rice-rice-green manure
rotation has increased the abundance of bacterial taxa such as Acinetobacter and
Pseudomonas which exerts bio-control and other plant beneficial traits [113]. Apart
from soil fertility, addition of compost in certain cases has positively enriched the
nutrient concentrations in rice [81]. Although positive attributes of organic supplements are noteworthy, heavy application of compost severely reduces soil bacterial diversity despite improving soil fertility and plant nutrition [92]. Recently, the
employment of industrial wastes (fly ash, phosphor-gypsum and slag) along with
agricultural bi-products (straw, baggase and biochar) are recommended as paddy
fertilizers [106]. In this aspect, use of steel slag coupled with biochar has documented significant C sequestration by reducing methane emission in rice field [2,
101]. The farmers of Cauvery delta in Tamil Nadu, India have a practice of applying
river sediments to rice paddies every alternate years which may be attributed to
the same. Although supplementation of organic and inorganic fertilizers imparts
varying effects on core microbiome, most of the studies conclude that combined
application of balanced chemical fertilizers with organic amendments would be the
best way to shape the microbial community and their functional diversity towards
paddy sustainability [26].
S. Ambreetha et al.
archaea on rice straw incorporation and rapid reduction in their count on addition of
nitrate based fertilizer [4]. In a crisp, CH 4 emission from paddy straw decomposition can be regulated through supplementing optimum dose of N fertilizer, thereby
suppressing global warming. In our studies, methanogenic archaea were inhibited
under flooded rice soils, owing to competition for H 2 with iron and sulphate reducers
and denitrifiers, however, addition of inorganic fertilizers acted as sources of electron donors thus improving the methanogenic flora and methane production [73].
While the methane oxidizers in oxic-anoxic interface, uptakes methane escaped from
anaerobic degradation of organic matter [12].
In north-eastern states of India, the paddy residues are burned resulting in waste
of essential nutrients apart from causing environmental pollution [62]. In such cases,
it is mandatory to create awareness and incline the farmers towards conversion agriculture and make the best N supplement out of paddy straw. Additionally, returning
paddy straw to the field creates huge shift in paddy-associated anaerobic microbiome by decreasing denitrifiers and encouraging the population of iron reducers
[100]. Paddy straw decomposition is rapidly carried out by hydrogenotrophic and
acetoclastic methanogenesis involving diversified bacteria and archaea of various
phyla [103]. Reconstruction of paddy associated soil microbial community is also
achieved by regular rotation with green manures. Long term rice-rice-green manure
rotation has increased the abundance of bacterial taxa such as Acinetobacter and
Pseudomonas which exerts bio-control and other plant beneficial traits [113]. Apart
from soil fertility, addition of compost in certain cases has positively enriched the
nutrient concentrations in rice [81]. Although positive attributes of organic supplements are noteworthy, heavy application of compost severely reduces soil bacterial diversity despite improving soil fertility and plant nutrition [92]. Recently, the
employment of industrial wastes (fly ash, phosphor-gypsum and slag) along with
agricultural bi-products (straw, baggase and biochar) are recommended as paddy
fertilizers [106]. In this aspect, use of steel slag coupled with biochar has documented significant C sequestration by reducing methane emission in rice field [2,
101]. The farmers of Cauvery delta in Tamil Nadu, India have a practice of applying
river sediments to rice paddies every alternate years which may be attributed to
the same. Although supplementation of organic and inorganic fertilizers imparts
varying effects on core microbiome, most of the studies conclude that combined
application of balanced chemical fertilizers with organic amendments would be the
best way to shape the microbial community and their functional diversity towards
paddy sustainability [26].