C4-Derived Soil Organic Carbon Decomposes Faster Than Its C3 Counterpart in Mixed C3/C4 Soils

Authors

Jonathan G. Wynn, University of South FloridaFollow
Michael I. Bird

Document Type

Article

Publication Date

10-2007

Keywords

C3-plants, C4, decomposition rate, soil organic carbon, stable carbon isotope

Digital Object Identifier (DOI)

https://doi.org/10.1111/j.1365-2486.2007.01435.x

Abstract

The large difference in the degree of discrimination of stable carbon isotopes between C3 and C4 plants is widely exploited in global change and carbon cycle research, often with the assumption that carbon retains the carbon isotopic signature of its photosynthetic pathway during later stages of decomposition in soil and sediments. We applied long-term incubation experiments and natural ¹³C-labelling of C3 and C4-derived soil organic carbon (SOC) collected from across major environmental gradients in Australia to elucidate a significant difference in the rate of decomposition of C3- and C4-derived SOC. We find that the active pool of SOC (ASOC) derived from C4 plants decomposes at over twice the rate of the total pool of ASOC. As a result, the proportion of C4 photosynthesis represented in the heterotrophic CO₂ flux from soil must be over twice the proportional representation of C4-derived biomass in SOC. This observation has significant implications for much carbon cycle research that exploits the carbon isotopic difference in these two photosynthetic pathways.

Rights Information

Terms of use for work posted in Scholar Commons.

Was this content written or created while at USF?

Yes

Citation / Publisher Attribution

Global Change Biology, v. 13, issue 10, p. 2206-2217

Scholar Commons Citation

Wynn, Jonathan G. and Bird, Michael I., "C4-Derived Soil Organic Carbon Decomposes Faster Than Its C3 Counterpart in Mixed C3/C4 Soils" (2007). School of Geosciences Faculty and Staff Publications. 224.
https://digitalcommons.usf.edu/geo_facpub/224