Hall et al., 2016

Paper/Book

Iron addition to soil specifically stabilized lignin

Hall, Steven J. Silver, Whendee L. Timokhin, Vitaliy I. Hammel, Kenneth E. (2016)
Soil Biology and Biochemistry  

Abstract

The importance of lignin as a recalcitrant constituent of soil organic matter (SOM) remains contested. Associations with iron (Fe) oxides have been proposed to specifically protect lignin from decomposition, but impacts of Fe-lignin interactions on mineralization rates remain unclear. Oxygen (O2) fluctuations characteristic of humid tropical soils drive reductive Fe dissolution and precipitation, facilitating multiple types of Fe-lignin interactions that could variably decompose or protect lignin. We tested impacts of Fe addition on 13C methoxyl-labeled lignin mineralization in soils that were exposed to static or fluctuating O2. Iron addition suppressed lignin mineralization to 21% of controls, regardless of O2 availability. However, Fe addition had no effect on soil CO2 production, implying that Fe oxides specifically protected lignin methoxyls but not bulk SOM. Iron oxide-lignin interactions represent a specific mechanism for lignin stabilization, linking SOM biochemical composition to turnover via geochemistry.

Citation

Hall, Steven J. Silver, Whendee L. Timokhin, Vitaliy I. Hammel, Kenneth E. (2016): Iron addition to soil specifically stabilized lignin. Soil Biology and Biochemistry. DOI: 10.1016/j.soilbio.2016.04.010

This Paper/Book acknowledges NSF CZO grant support.