Suppression of CH4 emission by rice straw removal and application of bio-ethanol production residue in a paddy field in Akita, Japan

Abstract

To elucidate the effects of rice straw removal and rice straw-based bio-ethanol production residue application on rice growth and methane (CH4) emission from a paddy field, a lysimeter experiment with three treatments (application of rice straw after harvesting (the rice-straw plot); removal of rice straw and the application of bio-ethanol production residue (the Et-residue plot); removal of rice straw (the no-application plot)) was conducted over three years. Though the grain yields in the Et-residue and no-application plots tended to be slightly higher than that in the rice-straw plot, there were no significant differences among the plots (530–546 g·m−2). Suppression of CH4 emission by the treatments was found clearly in the early part of the growing season. The total CH4 emissions during the rice-growing season (unit: g·C·m−2·period−1) followed the order of the no-application plot (11.9) < the Et-residue plot (14.6) < the rice-straw plot (25.4), and a significant difference was found between the no-application and rice-straw plots. Consequently, bio-ethanol production from rice straw and a following application of its residue to paddy fields is considered to be a promising technology which can obtain new sustainable energy and suppress CH4 emission without any inhibition on rice growth.