Sorption of organic carbon compounds to the fine fraction of surface and Subsurface Soils

Journal Article · Tue Dec 31 23:00:00 EST 2013 · Geoderma

DOI:https://doi.org/10.1016/j.geoderma.2013.07.030· OSTI ID:1092195

Jagadamma, Sindhu ^[1]; Mayes, Melanie ^[1]; Zinn, Yuri ^[2]; Gisladottir, Gudrun ^[3]; Ann, Russell ^[4]

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1. ORNL
2. Federal University of Lavras, Brazil
3. University of Iceland
4. Iowa State University

Dissolved organic carbon (DOC) transported from the soil surface is stabilized in deeper soil profiles by physicochemical sorption processes. However, it is unclear how different forms of organic carbon (OC) compounds common in soil organic matter interact with soil minerals in the surface (A) and subsurface (B) horizons. We added four compounds (glucose, starch, cinnamic acid and stearic acid) to the silt- and clay-sized fraction (fine fraction) of A and B horizons of eight soils from varying climates (3 temperate, 3 tropical, 1 arctic and 1 sub-arctic). Equilibriumbatch experiments were conducted using 0 to 100 mg C L 1 of 14C-labeled compounds for 8 h. Sorption parameters (maximum sorption capacity, Qmax and binding coefficient, k) calculated by fitting sorption data to the Langmuir equation showed that Qmax of A and B horizons was very similar for all compounds. Both Qmax and k values were related to sorbate properties, with Qmax being lowest for glucose (20 500 mg kg 1), highest for stearic acid (20,000 200,000 mg kg 1), and intermediate for both cinnamic acid (200 4000 mg kg 1) and starch (400 6000 mg kg 1). Simple linear regression analysis revealed that physicochemical properties of the sorbents influenced the Qmax of cinnamic acid and stearic acid, but not glucose and starch. The sorbent properties did not show predictive ability for binding coefficient k. By using the fine fraction as sorbent, we found that the mineral fractions of A horizons are equally reactive as the B horizons irrespective of soil organic carbon content.

• Research Organization: Oak Ridge National Laboratory (ORNL)
• Sponsoring Organization: ORNL LDRD Director's R&D
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1092195
• Journal Information: Geoderma, Journal Name: Geoderma Vol. 213; ISSN 0016-7061
• Country of Publication: United States
• Language: English