Dear authors,

I have now checked, with some delay, your revised manuscript. I think that significant progress has been made in comparison to the first version, but I also think that the manuscript needs significant additional work before it can be published. The main reasons for this are as follows:

- The English used is not yet up to international standards. The paper really needs a revision by a native speaker
- The structure of the paper needs improvement. Now, there is still to much mixing of methods, results and discussion. Furrthermore, the results are not all well presented: you report that dolostone and limestone tables were used but only discuss the limestone results because the dolostone results were similar. I would suggest all avaialble data should be presented, at least in tabular form in an appendix and that at least a graph is included showing that the results are indeed similar.
- With respect to the structure of the paper, the following guidelines may be useful to you:

Introduction: explain the state of the art.
- Weathering may be impacted by mineral fertilization
- But impact of different types of fertilizers not known
- Therefore we conducted experiments

Materials and methods:
- Description of the experimental set up
- study area, including meteo data and more infor on the soil (grain size Ph, SOC content in a small table)
- columns : size, way of filling, resulting bulk density of the soil.....
- measurement procedure for the tablets and presentation of the way losses are calculated
- the description needs to include a justification of some or your decisions on the methods: why this size of columns ? Why 30 times more fertilizer ? Why did you choose this length for the measuring period ?

Results
- Presentation of the results: no discussion and no further justification of the study or certain decision taken
- Presentatiion of the weathering rates
- Statistical analysis : for which treatments are rates significantly different: this can be done with an ANOVA analysis. I suggest to include the type of tablet as a class variable here so that we can see whether or not the results for limestone and dolostone are similar


Discussion

- A key element in the discussion are the weathering reactions: I suggest to have the generic weathering reactions in the text (paragraph 4.2) and then have the fertilizer-specific reactions in a table. In this table you can then also indicate the amount of NH4 per mole of fertilizer
- After having done this you can proceed to discuss the differences between the treatments. I think this is already more or less covered in the current version of the MS but it needs to be presented more clearly
- Then you may discuss the fact that CO2 consumption by weaterhing may be wrongly estimated if the contributions of (different) fertilizers is not accounted for
- Finally you have to compare your results with other data: now, there is no quantitative comparison whatsoever with results from other studies. Nevertheless, this is possible: you can calculate a weathering rate from your results and make than reasonable assumptions to make a calculation for larger areas that could be compared to the results of earlier studies whcih you already cite.


You will find more of my notes in the attached MS. Please consider them carefully. I invite you to submit a revised manuscript as quicliy as you can. The manuscript will be sent out again for review.

Kind regards, Gerard Govers

Dear Dr. Song,

I have now read and evaluated the review reports on your manuscript. As you can see both reviewers are in principle in favour of publishing the manuscript. However, both have concerns with the present shape of the manuscript: their remarks mostly focus on the description of the experimental procedures.

Please take into account their remarks very carefully and resubmit your manuscript after having taken into account all remarks.

Kind regards, Gerard Govers

Thank you for submitting your revised manuscript to ESurf. Our apologies for the delay in processing your work, which was related to the Associate Editor stepping down, and unforeseen constraints on my own time.

I have now read your initial submission, the two public reviews, your response to the reviews and your revised manuscript. Overall, I agreed with the general assessments that the new measurements and the authors conclusions are important for understanding how carbonate weathering rates vary, and how they may change due to agricultural activities impacting catchments.

I see significant improvements from the original submission, guided by the reviewer comments. While there are clear challenges to upscaling an experimental study such as this (some of the concerns in the reviews), the revised manuscript is much clearer on what was done, and where the limitations lie.

I am happy to recommend publication at ESurf following these extensive revisions which address the main comments raised.

Best regards,
Bob Hilton
AE ESurf

The Reviewers, Associate Editors, and I all agree that this paper presents results that are important for understanding the effect of agricultural practices on carbonate weathering rates, with implications for CO2 fluxes. The experimental approach has inherent limitations but has allowed the authors to identify important distinctions between the effects of different types of fertilizers, and despite its limitations, I hope this study will stimulate further work on the topic. The paper has improved considerably through the review process, and I am happy to accept it for publication in Earth Surface Dynamics. However, there are additional technical corrections that need to be addressed before it is published. These can be dealt with at this final submission stage rather than going through another stage of review.

Both reviewers from the latest round of reviews asked for more details on how the experiment was set up in the field. Some changes have been made but more detail is needed. The design of each column is clear, but how they were placed in the field needs more description. If you do not have a photograph, perhaps a schematic diagram could be added as an additional figure, in addition to a couple of sentences to the text.

Both reviewers also asked how the amount of fertilizer used was determined. Although these questions were answered in the reply document, no changes were made to the manuscript. Please add a couple of sentences to the manuscript to describe how the fertilizer amounts were decided, and how they compare to the amounts used on agricultural fields.

Some statements in the Results section are not technically correct, related to whether or not observed differences between the experiments were significant. For example, at lines 198-199, the text says that “The remaining treatments made no significant differences in the Rw and Raw of limestone and dolostone in comparison to the control treatment.” However, several of these treatments did show statistically significant differences relative to the control, based on the results in Table 2. For example, the Raw for limestone with NH4Cl was 4.43±1.73, compared to the control value of 2.00±0.58. This is a statistically significant difference, though it is much smaller than for the other fertilizers. It is thus not correct to say that the changes observed with NH4Cl were insignificant. Please change the wording of the text to note that the differences were much smaller for these treatments, but that they were in some cases still statistically significant.

The following should also be corrected to fix grammatical errors or statements that are unclear:

Line 70: “world”, not “global”
Line 76: 100% OF NO3-
Line 78: “a deviation”, not “an evaluated deviation”
Line 87: remove “fully” – this study cannot on its own achieve full understanding of these effects
Line 97: remove However
Line 102: “the preferred method” is subjective – as you say at the end, it is also possible to measure rates hydrochemically, and preference is largely down to different researchers – suggest replacing with “a well-established method” or similar language
Line 124: which WAS sampled
Section 2.2: I would prefer to see a sentence added to clarify how the concentrations of each solute in your extractions (e.g., P, K, Ca, Mg, Fe, and S) were analyzed
Line 149: These, not there
Line 158: What does “orderly” mean? This needs more detail in my opinion. See above.
Line 166: on, not in
Line 193: The differences are significant, just not as significant as for the treatments with NH4-based fertilizers. Please reword.
Line 199: Again, the differences were statistically significant, though small.
Line 205: Remove the mention of the common ion effect here. This is discussion, not results, and is repeated in Section 4, where it is more appropriate.
Line 208: except FOR THE (NH4)2CO3 treatment
Line 208: demonstrating, not exhibiting
Line 209: weathers, not weather
Line 215: suggest rewording to “rather than separately discussing the individual…”
Line 235: probably, not probable
Line 254: remove the formula for urea here, since it is specified in the line above
Line 270: remove “supposedly”
Line 306: provide a citation here for the effect of PO4 inhibiting calcite (and dolomite) dissolution
Line 314: provide a citation here for the effect of PO4 inhibiting calcite (and dolomite) precipitation
Line 317: differences, not differenceS
Line 318: amounts, not amount
Line 320: I assume you mean “1.06 moles NH4 per mole urea”? Please specify
Line 321: same issue with units as line 320
Line 329: demonstrated, not proven
Lines 335-337: any reference to support the argument that these fertilizers are easier to decompose and produce NH3?
Line 344: remove “more or less relative to” which does not make sense as an English expression
Line 350: remove “However, in Fig. 3”
Line 355: remove “on”
Line 357: remove “process”
Line 372: remove “double”
Line 376: become, not became
Line 392: AN orchard
Line 397: remove comma in Zeng et al. citation
Line 399-400: remove “due to its own limits in methodology” which is an unclear statement
Line 400: remove comma in Semhi et al. citation
Line 407: remove comma in Amiotte Suchet et al. citation
Line 415: need a space before (Yue et al., 2015)
Line 427: note as above, that there is an effect on carbonate weathering, just much smaller than for other fertilizers
Table 4, column 4: change to “molar amount NH4/mole fertilizer”
Figure 2: I assume the bottom 2 cm are the gravel and sand – change the shading to illustrate this difference, and/or add a label on the left side of the figure