Terrestrial ecosystems can play important role in carbon sequestration. The loss of wetlands for croplands results in a release of significant amount of carbon from soil organic matter into atmosphere. Wetland restoration from croplands has the potential for carbon sequestration. The overall goal of this study is to quantify how SOC storage in two restored wetlands with various ages changes over time. The wetland restoration of Emiquon and Spunky Bottoms in Illinois was launched in 2007 and 1997, respectively. In the summer of 2007, we collected soil samples from both restored wetland sites and one corn field.
Results/Conclusions
The average SOC concentration of the two restored wetlands increased while the average soil bulk density decreased with restoration ages. For the top 20 cm soil, the average SOC in Emiquon and Spunky Bottoms was 1.83% and 1.95% in comparison with an average of SOC of 1.04% in a corn field adjacent to Spunky Bottoms site. For the same soil depth, soil bulk density of these two restored wetlands was 0.72 g/cm3 and 0.67 g/cm3, respectively. However, the average SOC storage of the top 20 cm soil in Emiquon and Spunky Bottoms was similar with a value of 26 Mg/ha, although this value was greater than the average SOC storage of 20.6 Mg/ha in the corn field. Our study suggests soils in restored wetlands have potential for storing more carbon. The enhanced carbon sequestration may be compromised by the increasing methane emission in these restored wetlands because global warming potential (GWP) of methane is greater than carbon dioxide.