The manuscript has been greatly improved and now needs only fairly minor edits prior to publication. Numerous edits were made on a pdf throughout the text. Please open the annotated pdf and address the edits and corrections (easy to see in Adobe Acrobat Pro under view>comment>review), which are intended to improve the readability and accessibility of the manuscript.
The abstract must be improved in order to attract a wide audience. The grammar is not as good as it could be, although the main ideas do come across pretty well. Please consult with all coauthors to ensure a high-impact abstract is written.
In the results, table 2, what is the difference between “start time after sampling” and “incubation time”? Are both these columns necessary?? Perhaps come up with more descriptive names for the headers if they are important.
The discussion section is still too long and speculative, with repetition of the results. Really, the manuscript will be better received if the discussion can be focused and shortened by about two pages. IN particular, the first 2 paragraphs are technical and detailed, and therefore not compelling. Start with a short paragraph highlighting the main 2-3 points, then revise the rest of the discussion to address only those points. For instance:
Point 1: Soil CO2 efflux is not always a good indicator of biological respiration rates.
Point 2: ARQ can indicate non-respiratory sources or sinks of CO2: 2a) in calcareous soils; 2b) with substrate limitations; 2c) oxidation of reduced iron

Thank you for submitting your revised manuscript which can be published after technical corrections have been made as described below.