The Spatial Variability of CO2, CH4, and N2O Gas Concentration in the Soil of Rice Paddy Fields.

In recent years, global climate change has become one of our biggest concerns. Increases in greenhouse gases (GHGs) emission may be attributed to the global warming. Rice paddy fields are one of the major sources of GHGs for the agricultural sector in monsoon Asian countries. Rice paddy fields mainly emit carbon dioxide (CO₂), methane (CH₄), and nitrogen oxide (N₂O) gases. A previous study reported that within the same rice paddy field, there was a spatial variability for GHGs flux. Soil physical and chemical properties in rice paddy fields spatially varied as well. The objective of this study was to investigate the spatial variability of CO₂, CH₄, and N₂O gas concentrations in the soil of a rice paddy field. We will periodically measure the soil GHGs concentrations and GHGs soil surface fluxes at several locations. The locations are the center of the rice paddy field, water inlets, and water outlets in the rice paddy field. For measuring CO₂, CH₄, and N₂O gas concentration in soil, we use gas-permeable silicone tubings. For measuring soil surface CO₂, CH₄, and N₂O fluxes, we use the closed chamber method. We analyze soil physical and chemical properties. We will discuss the spatial variability of CO₂, CH₄, and N₂O gas concentrations in relations to soil physical and chemical properties.