Factors Related with CH(4) and N(2)O Emissions from a Paddy Field: Clues for Management implications

Paddy fields are major sources of global atmospheric greenhouse gases, including methane (CH(4)) and nitrous oxide (N(2)O). The different phases previous to emission (production, transport, diffusion, dissolution in pore water and ebullition) despite well-established have rarely been measured in field conditions. We examined them and their relationships with temperature, soil traits and plant biomass in a paddy field in Fujian, southeastern China. CH(4) emission was positively correlated with CH(4) production, plant-mediated transport, ebullition, diffusion, and concentration of dissolved CH(4) in porewater and negatively correlated with sulfate concentration, suggesting the potential use of sulfate fertilizers to mitigate CH(4) release. Air temperature and humidity, plant stem biomass, and concentrations of soil sulfate, available N, and DOC together accounted for 92% of the variance in CH(4) emission, and Eh, pH, and the concentrations of available N and Fe(3+), leaf biomass, and air temperature 95% of the N(2)O emission. Given the positive correlations between CH(4) emission and DOC content and plant biomass, reduce the addition of a carbon substrate such as straw and the development of smaller but higher yielding rice genotypes could be viable options for reducing the release of greenhouse gases from paddy fields to the atmosphere.