If the author of this work had measured soil microbial biomass carbon, they might have seen a different result.  Measures of biomass-specific soil respiration have been shown to indicate when the microbial biomass is under stress e.g. https://doi.org/10.1016/0038-0717(91)90171-F; https://doi.org/10.1016/0038-0717(94)90144-9, as a couple of examples. 

 Dr Hart,

Thank you for your valuable insight,  I agree with you 100% that microbial biomass C is a good indicator that gives better prediction on the quantity of microbes in a given sample. My concern is in that, SR doesn't necessarily tell you accurately  about the quantity of microbes and whether the respiration comes from good or bad bacteria. I find it quite worrying that SR did not correlate with any of the soil biology indicators that were measured. Theoretically, isn't SR supposed to positively correlate with total C, active C and PMN? I have interacted with a number of people here on RG and out side of RG who have found questionable results from their soil respiration analysis by titration. Which brings me to ask, is this titration method accurate in its measurement?

Regards

P

It is very relevant. Microbial biomass and respiration can be significant in many substrates, even in sand dune ecosystems (I'm answering your actual question btw) :)