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Assessment of Labile Organic Carbon in Soil Using Sequential Fumigation Incubation Procedures
Published on: October 29, 2016
Dissolved organic carbon fluxes under bare soil
Jan Mertens1, Jan Vanderborght, Roy Kasteel
1Soil and Water Management, K.U. Leuven, Celestijnenlaan 200E, B-3001 Heverlee, Belgium. mertensja@yahoo.co.nz
Journal of Environmental Quality
|March 3, 2007
Summary
Dissolved organic carbon (DOC) flux in soil is mainly driven by water movement, not concentration. Water velocity influences DOC levels, potentially limiting contaminant transport to groundwater.
Area of Science:
- Soil Science
- Environmental Chemistry
- Hydrology
Background:
- Dissolved organic carbon (DOC) flux is crucial for nutrient and contaminant transport in soils.
- Limited data exists on DOC fluxes and their relationship with water flux in agricultural soils.
Purpose of the Study:
- To investigate DOC fluxes and concentrations in agricultural soil.
- To determine the relationship between DOC concentration and water flux.
- To assess the factors influencing spatial variability in DOC fluxes.
Main Methods:
- Utilized 30 automatic equilibrium tension plate lysimeters (AETPLs) at 0.4m and 1.2m depths over 2.5 years.
- Measured DOC fluxes and concentrations in leachate.
- Analyzed relationships between DOC, water flux, soil moisture, temperature, and water velocity.
Main Results:
- Average annual DOC fluxes were 4.9 g C m⁻² y⁻¹ at 0.4m and 2.4 g C m⁻² y⁻¹ at 1.2m.
- DOC concentrations averaged 17 mg C L⁻¹ (0.4m) and 9 mg C L⁻¹ (1.2m), largely independent of moisture and temperature.
- Spatial variability in DOC flux was linked to leachate volume, indicating water flux as a primary driver.
Conclusions:
- Water flux is the main determinant of spatial variability in soil DOC fluxes.
- DOC concentrations are inversely related to water velocity, suggesting a limited topsoil DOC mobilization rate.
- Low water velocities correlate with higher DOC concentrations, potentially reducing contaminant transport risks to groundwater.
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