Part of the book: Biomass
Submerged rice paddy soils are one of the major anthropogenic sources of methane (CH4) emission to the atmosphere. Methane is the second most important greenhouse gas after carbon dioxide. Methanogens are strictly anaerobic microorganisms and CH4 is the metabolic end product of those methanogens. Methane is produced by methanogens through multi-step enzyme-mediated process. Methanogens convert labile organic carbon compounds in CH4 and application of organic matter in submerged rice field significantly increased CH4 emission from soil to the atmosphere. The rate of methanogenesis may be determined by quantifying biomarkers namely methyl coenzyme M reductase A (mcrA) gene and coenzyme M (2-mercaptoethane sulphonate) in soil. Nickel ions are present as cofactor in enzymes involved in methanogenesis. Methane emission can be mitigated by application of EDTA at suitable rate in the soil of submerged rice field.
Part of the book: Rice Crop
Climate change is a vital environmental issue for the twenty-first century, which may significantly affect rice productivity and accelerate greenhouse gas emissions from paddy ecosystem, which is of great environmental concern which is of great environmental concern. Methane (CH4) and nitrous oxide (N2O) are the most important greenhouse gases due to their radiative effects as well as global warming potentials (GWPs). CH4 and N2O gases are simultaneously emitted from rice fields to the atmosphere due to their favorable production, consumption, and transport systems. The intensive rice farming system has been creating excessive pressure on rice fields to produce more rice for the expanding world population, thereby deteriorating soil fertility status and rice paddy ecosystem balance by stimulating more CO2, CH4, and N2O fluxes to the atmosphere. The extreme climatic variables such as high light intensity, high water vapor or relative humidity, high temperature, and drought stress may badly suppress beneficial microbial activity, soil nutrients, and water availability to rice plant; eventually, rice yield may be decreased drastically, and simultaneously, greenhouse gas emissions could be increased significantly. In this situation, conservation tillage, water saving irrigation technique such as alternate wetting and drying, soil amendments with biochar, vermicompost, azolla-cyanobacterial mixture, recommended silicate slag, and phospho-gypsum with minimum NPKSZn fertilizer (IPNS) should be introduced to the field level farmers for sustainable rice production and mitigating greenhouse gas emissions.
Part of the book: Soil Contamination and Alternatives for Sustainable Development