Publication date: June 2014
Source:Geoderma, Volumes 221–222
Author(s): Paul L. Drake , Caroline A. McCormick , Michael J. Smith
The total efflux of CO2 derived from metabolic processes in soil (R soil ) exerts a large control on the terrestrial carbon balance. In landscapes that have been radically transformed by humans, the natural carbon balance may be altered by shifts in R soil . After accounting for temperature, we sought to determine the main factors that govern R soil at Toolibin Lake, an ephemeral wetland threatened by salinization as a result of land clearing. We found strong statistical support for a positive effect of soil gravimetric water content (θ) on R soil and weaker support for a negative effect of salinity (measured as the electrical conductivity of a soil extract (ECe )) on R soil . We also detected weak support for a positive interaction between θ and ECe , such that θ had a greater positive effect on R soil at elevated soil salinities. These results confirm not only that soil moisture is an important driver of R soil under native conditions, but also that elevated soil salinities have the potential to accentuate the link between R soil and moisture content.
Source:Geoderma, Volumes 221–222
Author(s): Paul L. Drake , Caroline A. McCormick , Michael J. Smith