17:15 〜 18:30
[AGE27-P02] Impact of Macropore structure and water management on greenhouse gas emissions, total soil carbon and nitrogen, and soil mineral distribution in agricultural field
キーワード：GHG, Macropore, Soil total carbon, Total nitrogen, Soil mineral, Drainage
Greenhouse gas (GHG) emissions generated from soils have become the prevailing concern due to their contribution to global warming. Several studies have been conducted under the diversity of objectives, methods, and disciplines recently. The emissions generated from soil are significantly influenced by soil factors, such as water content, soil organic matter, redox potential, hydraulic conductivity, and pore structure.
In this study, a preliminary experiment was conducted to observe the effects of macropore structure and water management on agricultural soil GHG emissions, total soil carbon, nitrogen, and mineral distributions under different management practices. Masa soil was prepared with/without macropores and with/without compost application under unsaturated/saturated conditions, while paddy soil was examined the same preparation under with/without drainage.
The results for the Masa soil with macropores showed that CO2 gas emissions were more extensive due to an increased pathway for gas emission. There was no clear trend in total carbon (TC) and total nitrogen (TN). However, Ca and Mg were larger at the surface of soils without macropore because of the salt accumulation process. Paddy soil with macropores also showed larger CO2 gas emissions but CO2 and CH4 gas emissions were smaller with drainage application in soils with macropores and compost application. CH4 gas concentration was negatively correlated with infiltration rate, which meant that freshwater or oxygen supply was available within macropore pathways and drainage application. TC and TN were significantly smaller at the bottom than at the top of the soil sample, showing the development of the reductive conditions with no drainage. The findings showed that macropores act as pathways for gas emission while reducing reductive conditions, leading to lower CH4 emissions.
In this study, a preliminary experiment was conducted to observe the effects of macropore structure and water management on agricultural soil GHG emissions, total soil carbon, nitrogen, and mineral distributions under different management practices. Masa soil was prepared with/without macropores and with/without compost application under unsaturated/saturated conditions, while paddy soil was examined the same preparation under with/without drainage.
The results for the Masa soil with macropores showed that CO2 gas emissions were more extensive due to an increased pathway for gas emission. There was no clear trend in total carbon (TC) and total nitrogen (TN). However, Ca and Mg were larger at the surface of soils without macropore because of the salt accumulation process. Paddy soil with macropores also showed larger CO2 gas emissions but CO2 and CH4 gas emissions were smaller with drainage application in soils with macropores and compost application. CH4 gas concentration was negatively correlated with infiltration rate, which meant that freshwater or oxygen supply was available within macropore pathways and drainage application. TC and TN were significantly smaller at the bottom than at the top of the soil sample, showing the development of the reductive conditions with no drainage. The findings showed that macropores act as pathways for gas emission while reducing reductive conditions, leading to lower CH4 emissions.