Dear Dr. Rinderer and colleagues,

As you have seen, the reviewers are generally positive about your study. I also appreciate the vast amount of work that went into this elaborate field experiment that generated very interesting data. Reviewer 1 raised however an important point: you present water fluxes and P concentrations, but failed to calculate the obvious thing: P fluxes. In your answer you refer to another manuscript that you are working on, which specifically deals with P fluxes. For an editor, this is frankly not very satisfying, because how do you guarantee that the present publication is not obsolete, the moment the second will be published? Again, I appreciate the vast amount of work that went into this experiment and I can understand that you want to get the necessary impact out of it. On the other hand I am not a big fan of splitting data to get more publications. So, please reconsider whether it is smart to publish the P fluxes in a seperate paper, or provide good scientific arguments why is is worth published the concentrations and water fluxes separately from the P fluxes. In any case I expect that, independent of your decision, substantial changes will be necessary to your manuscript because at present a lot of the introduction is focussing of P fluxes even though they are not part of the results.

Best regards,

Edzo Veldkamp

Dear Dr. Rinderer and colleagues,

I have now read your revised manuscript and the reviews provided by the two referees.
You will also see that the referees made some contrasting recommendations based on your revised manuscript. Referee #2 is very positive about the changes in the direction of the manuscript, Referee #1 expresses some concerns, although this referee continues to be very positive about the overall scientific significance and quality of your study.
I would like to commend you for taking the reviews seriously and making considerable changes to your original manuscript based on the earlier reviews. I think that the manuscript has improved substantially, both in focus and the message it conveys. Nevertheless, I would recommend some additional changes which I would consider relatively minor:
-Referee 1 expresses concern that the importance of nutrient flushing is not sufficiently stressed in your discussion. My impression from your results is that the nutrient flushing was not contributing enough (both in terms of waterflow and P concentration) to have a significant effect on the annual P losses from your ecosystem and so your approach to calculate annual P fluxes appeared reasonable. However, referee #1 makes a good point when referring to line 400, in which you cite another study which claims that up to 40% of the annual P flux may occur during single events. Does this mean that your study results deviate from this earlier study? To address the concerns of Referee #1, I suggest to include in your discussion a short section in which you address what the potential error is when nutrient flushing during single events is ignored in your annual budget.
-Referee #1 also suggests to include the effect of different tree species. Because your study sites were all dominated by beech trees I do not see that your study can contribute much new information to this interesting question. As your manuscript is already relatively long, I suggest not to explore this further in your present manuscript.
Both referees have also also added a list of specific comments, which I would like you to address. Especially the statistics should be described if you conducted them.
A few additional suggestions:
-In your response you write about ‘quantitative, hypothesis-driven … test’ (l.49). Unfortunately, you did not write out your hypotheses in the introduction, which I strongly recommend.
-Fig.1: I suggest to add error bars to the measured bulkdensity data and to connect the bulkdensity data with straight lines (unless you have a good scientific reason why you used non-linear interpolation).
-L. 250: I suggest to use ‘detection limit’ instead of ‘limit of quantification’. ‘Detection limit’ is not only used for analyses done by analytical equipment but can also include data processing steps.

I look forward to your revisions,

Best regards,

Edzo Veldkamp

Dear Dr. Rinderer and colleagues,

it is my pleasure to accept your manuscript for publication in Biogeosciences. I think your study gives important new insights in the behaviour of phosporus in forest ecosystems and I am sure that it will attract substantial attention of colleagues working in this area. Thank you very much for submitting your interesting study to Biogeosciences.

Best regards,

Edzo Veldkamp