Dear Dr Valadares,

Many thanks for responses to referee comments. Most of the referees thought that your research was of interest, at least in principle, but that significant work was needed to make the manuscript publishable. In view of general and detailed comments, as well as your response to these, I think that a very substantial revision is required.
You manage to defend some of the criticism reasonably, but there are several instances where I think you fail to appreciate the referees’ points, and you have to adapt your text to accommodate concerns. For example, referee #2’s point regarding an apparent assumption that larger diameter roots have more influence on rhizosphere effects highlights an area where your presentation was not sufficiently clear. Rather than correcting the referee and insisting that your point is correct, you should make sure that the way you present C allocation in relation to root diameter is absolutely clear to readers.
The same applies to many of your responses, where you should make sure that any misunderstanding highlighted by a referee comment is not a fault of the referee, but of the clarity of your presentation.
The discussion needs to capture more of the criticism voiced by referees, rather than just review findings. You are clear about the fact that the model does not include feedback between priming and plant growth. This would be desirable, but was not art f your approach – it should be discussed as an important current gap and area for improvement in future research.
In your conclusion, please present a continuously phrased paragraph, rather than bullet points. Instead of simply repeating results, your conclusions should state clearly what the key outcome of your presented research is, and how it advances our understanding.

There are a couple of specific comments below I picked up from referee comments and your response to them below. Overall, I think that substantial revision is required for this manuscript to be ready for publication. I will ask referees to once again look at your revised manuscript, whoch I trust will have addressed all concerns meaningfully.

Best wishes,
Jens-Arne Subke

P. 1, Line 13: Please replace “for instance” by “including”, as suggested by refere #2 P. 1, Line 19: Add “and” before “SOM formation”, as suggested by referee #3

P. 2, l. 31: The sentence clearly suggests that the authors mentioned developed the MCNiP model to specifically investigate rhizospheric N cycling (comment referee #3). If this is not actually the case, then this has to be re-phrased to reflect what precisely these authors did to develop the model.

Dear Dr. Valadares,

I have looked through your responses and revised manuscript. You successfully address most of the concerns raised by referees, and I’m minded to publish this manuscript. However, there are a good number of remaining issues (outlined below) that I would like you to address in a final revision.

I hope you will be able to implement these revisions.

With best wishes,
Jens-Arne Subke


Manuscript comments:
P. 3, l. 8: “Eucalyptus rhizosphere cycling” is too vague. Make it clearer what you are aiming to model (i.e. C cycling only, or C&N combined?)

p. 3, l. 19: No hyphen after “involves”.

p. 3, l. 19: This is very Eucalypt-specific. Do you envisage this model to be applicable to other species (based on appropriate parameterisation), or is it specific to Eucalypts only? In that case, should the name of the tale reflect this?

p. 5, l. 16-33: Something seems to be missing here. The section aims to outline modelling of microbial turnover, and you provide an overview of what is known about moisture and temperature effects. However, you don’t indicate how this is then incorporated into ForPRAN. From the presentation, I would assume that moisture and temperature affect soil porosity, which is how microbial dynamics are implemented in eth model. Is that correct?

p. 8, l. 23-27: I propose a simplification of the text: “A linear model of the type O = 𝛃1P + 𝛃0 was fitted, where P is the value predicted by the model, and O is the value observed in field experiments. Model performance was evaluated through the coefficient of determination (R2). In addition, coefficient 𝛃1 was tested for significant difference from 1, and coefficient 𝛃0 for significant difference from 0 using t-tests.

p. 9, l. 20/21 (Figure caption): Simplify to: Correlation of fine root biomass reported in literature against values predicted using the ForPRAN model. The dotted line is the mean regression, with neither intercept nor slope significantly different from 0 or 1, respectively. Solid line: 1:1 relationship.

p. 10, l. 16/17 (Caption of Fig. 4): Change to: Regression of microbial biomass observed by Drake et al. (2013) against results. Regression parameters were not significantly different from 1 (slope) and 0 (intercept), respectively.” [explain insert table in graph]

Pages 17 and 18: The figure captions are too short. These are modelled responses, right? State this clearly in the caption, so the reader can obtain all information necessary to understand the figure without reading the text! Please include the sol depth in the caption of Figure 10.
P. 19, l. 5-8: This sentence is ambiguous. I think you’re saying that you combine two models, one designed to simulate rhizosphere C and N dynamics, and another that simulates wood production. However, it reads more as if you have expanded an existing C/N model and now have a new product that simulates wood production. Please rephrase.

Dear Dr Valadares,

Many thanks for including the edits suggested in the last revision. I am now happy with the state of the manuscript, except for one issue that I myself overlooked last time. Table 3 is not very clear, I don;t know what the numbers 15 and 30 in the first line indicate. It also isn't referred to in the text, which is not appropriate. Is this table necessary? If so, make sure it is well integrated to the text, and that all parts of it are clear.

Best wishes,
Jens-Arne Subke