09:45 〜 10:00
[AGE28-04] Enhanced Rock Weathering Impact on Soil CO2 Dynamics: A Soybean Field Monitoring Study in Hokkaido
キーワード：鉱物風化、二酸化炭素、野外調査、粉砕玄武岩、土壌物理性
Enhanced rock weathering (ERW) is a technique applying crushed rock powders in agricultural lands to enhance the weathering process, storing CO2 for negative emission. Researchers investigated several benefits of ERW, such as acidity amelioration, nutrients supply, and CO2 reduction. However, understandings of how rock powders affect the soil physicochemical properties and CO2 dynamics at field-scale are limited.
In this study, monitoring was conducted in an experimental field (grey lowland soil) at Hokkaido University (43.07 N, 141.34 E), where soybean (Glycine max) was cultivated in 2023. Continuous data of soil CO2, O2, moisture, EC, temperature, and water potential has been collected at depths of 10cm, 25cm, and 40cm, respectively, in four treatments [BNC (Basalt-No crop), BC (Basalt-Crop), LC (Lime-Crop), and NBC (NoBasalt-Crop)]. We also calculated the CO2 flux and CO2 production rate in each soil profile.
Soil CO2 concentration in all treatments increased after rainfall events. Basalt and lime applications in soybean plots significantly increased CO2 concentration at 10 cm depth. The estimated CO2 flux from 10 cm depth to the atmosphere based on the observed soil CO2 gradient was higher for the BC plot (accumulative CO2 flux until December 1st: 41.6 mol C m-2) as compared to the NBC plot (33.6 mol C m-2). The higher CO2 emission in ERW plots may indicate enhanced soil respiration due to the dissolution of rock powders (i.e., increase of pH).
In this study, monitoring was conducted in an experimental field (grey lowland soil) at Hokkaido University (43.07 N, 141.34 E), where soybean (Glycine max) was cultivated in 2023. Continuous data of soil CO2, O2, moisture, EC, temperature, and water potential has been collected at depths of 10cm, 25cm, and 40cm, respectively, in four treatments [BNC (Basalt-No crop), BC (Basalt-Crop), LC (Lime-Crop), and NBC (NoBasalt-Crop)]. We also calculated the CO2 flux and CO2 production rate in each soil profile.
Soil CO2 concentration in all treatments increased after rainfall events. Basalt and lime applications in soybean plots significantly increased CO2 concentration at 10 cm depth. The estimated CO2 flux from 10 cm depth to the atmosphere based on the observed soil CO2 gradient was higher for the BC plot (accumulative CO2 flux until December 1st: 41.6 mol C m-2) as compared to the NBC plot (33.6 mol C m-2). The higher CO2 emission in ERW plots may indicate enhanced soil respiration due to the dissolution of rock powders (i.e., increase of pH).