Abstract
In this study, we investigated the production of CO2, CH4, and N2O gases in the soil and their emission into the atmosphere using an indoor pot experiment, focusing on the soil dry bulk density and the difference between soybean cultivation and non-cultivation. As a result of the experiment under three types of soil bulk densities, it was confirmed that the difference in water infiltration and evaporation in the pores due to the difference in dry bulk density caused differences in the distribution of soil water and nitrogen within the pot, causing the surface layer to become oxidized, producing CO2 and N2O, consuming CH4. As the depth increased, the amount of production and consumption decreased. Since this effect was large under the dry bulk density of 0.67 Mg m-3, it was thought that the magnitude of water movement, gas movement, and solute movement in pores were related. In addition, differences in the amount of infiltration water affected the movement of dissolved gases, and the movement of nitrogen, which is a substrate for gas production. This resulted in differences in gas concentration in the soil, which subsequently affected the gas flux and production amount. Effects of soybean were observed in the production of N2O and CO2 in the soil and the large sink of CO2 at the soil surface. Soybean cultivation was able to clearly reduce greenhouse gas emissions, but this was due to the dynamics of CO2.
https://ror.org/00qg0kr10 
