Relationships between Soil Cracks and Behaviors of CO2, CH4 and N2O Gases and Soil Water in Paddyfield Soil.

Soil cracks develop in paddy soils during midseason drainage.　Greenhouse gas fluxes at agricultural fields are attributed to gas production and migration in soil. A major mechanism of gas migration in soil may be molecular diffusion, which is influenced by porosity, volumetric water content, and other physical properties of soil. During mid-drainage season, Porosity increased by soil cracks. Effects of soil cracks on gas behavior in midseason drainage are important to accurately estimate gas flux from the soil to the atmosphere. Our objectives were to investigate relationships between soil crack and fluxes of carbon dioxide (CO₂), methane (CH₄) and nitrous oxide (N₂O) in paddy field soil. Experimental site is located in the lysimeters in Meiji University, Kawasaki, Japan.