Enhancement of Greenhouse Gas Emissions by Hot Water Application for Soil Sterilization.

It is very important to find a new way of soil sterilization because the use of methyl bromide, which had been widely used all over the world, has been banned since 2005 in Japan and will be in the world by 2010. Using hot water for soil sterilization has become popular in Japan as an alternative for methyl bromide. However, few studies have been done because using hot water is relatively new. Especially, effects of hot water applied to soil on greenhouse gas emissions have rarely studied. Therefore, we investigated greenhouse gas emissions, such as methane(CH4), carbon dioxide(CO2), and nitrous oxide(N2O) after hot water application. Gas fluxes with and without hot water applied were compared. The gases were taken before and after the hot water application at a sterilized area and a non-sterilized area in a greenhouse. The closed chamber method was used to estimate gas flux. We predicted that gas emissions in the sterilized area decreased more largely than that in the non-sterilized area because bacteria would disappear in the vadose zone due to high soil temperature. However, our study showed that larger flux of greenhouse gases in the sterilized area than that in the non-sterilized area.