This study evaluates enhanced rock weathering using Greenlandic glacial rock flour applied to sandy agricultural soil in Denmark over five years. The research topic is timely and of interest to the EGUsphere reader community. The work is an extension and re-evaluation of work performed previously by the authors where they used an updated SOMBA framework to estimate ERW and CDR. While I agree that that the long-term 5-year evaluation is powerful, my impression is that this manuscript could be expanded and improved. Currently, its added benefit does not meet the expectations.  

 General comments:

1. The introduction may be written more concisely. There are several repetitions – for example on the surface area of GRF, and the fact that the data of the previous 3-yr study was re-evaluated in this study… I suggest re-organizing the paragraphs so that the introduction flows better and has less redundancies.
2. I am wondering regarding the use of sodium hexametaphosphate in the soil OM fractionation protocol – could the hexametaphosphate alter the native OM–mineral association? Various phosphates are commonly used to displace adsorbed OM due to their high affinity to mineral surfaces, so could the hexametaphosphate replace some of the MAOM?
3. The Discussion section seems slightly weak, and does not add significant insights to the results written before. For example, I do not see how the paragraph starting in line 482 adds anything that was not mentioned beforehand. Also, in the paragraph starting in line 519, the authors attribute the SOC gain to the MAOM pool, yet there were no statistical differences for the latter. This is missing a justification/explanation.
4. Throughout the paper, there are inconsistencies in formatting, capitalization of titles, subscripts (e.g., Table 1), difference in spacing (e.g., Table 2) and missing acronyms (e.g., line 143).
5. I am curious regarding the Si levels and trends in the experiments? Si dissolution is an important part of the ERW process, so why was this not even mentioned by the authors?

 Specific comments:

Lines 51-52 – I suggest adding here the actual particle size and surface area of the GRF.

Lines 52-53 – Is there literature or other reports confirming these claims?

Line 115 – Please add the exact texture as well.

Line 125 – It would be helpful to show the particle distribution and not only report the d₅₀.

Line 143 – Please spell out ICP-OES and add details of the instrument that was used.

Table 2 title – What is the time of sampling for Ti and mobile cations? Perhaps specify directly?

Lines 352-355 – To be clear, maybe first spell our what SD and CI represent?

Figure 1 – Missing what panels (a) and (b) are?

Lines 372-375 – The authors suddenly mention BET analysis measured over the 5-year period. There is no mention of this in the Materials and Methods, and it is unclear to me which samples exactly were measured? How were the samples prepped? Which instrument was used? Where are the results presented? This raises uncertainty as to the calculated surface-area-normalized rate of total alkalinity release.

Table 5 – The title does not describe what the Table actually presents.

Line 425-426 – Looking at the cited papers, it seems that the surface-area-normalized weathering rates reported for acidic conditions are within a wider range, including faster rates similar to those reported in this work.

Lines 535-536 – Are there studies supporting this?

General comments:

The paper contributes new, promising findings and methodological frameworks, specifically SOMBA, to account for Enhanced rock Weathering (ERW) rate estimates. I believe this to be an exciting and significant contribution to understanding effective carbon dioxide removal strategies (CDR), given that this was one of the few long-term field studies of five years duration. It also took into consideration both organic and inorganic carbon components. The improved and reevaluated methodology adds value and validity.  This looks promising for scaling of new technologies for carbon mitigation in temperate climate agricultural settings.

The methods section is very detailed and long. Given many technical components of data analyses, some ideas could be elaborated, and other sections could be shortened to reduce the length of the methods.  Some table captions in the results need re-evaluation. Results can be enhanced with more visual figures. The importance of temporal data assessment of cumulative responses of dissolution and weathering rates are mentioned in different parts of the manuscript, so a figure could be added as a visual graph to demonstrate this and add a clear message in the Results.

Specific comments:

1. Line 143, Section 2.4: what is ICP-OES? It wasn’t mentioned before
2. Line 200, Section 2.6 (or following related sections) could use more explanation on what the different linear mixed effects model designs were. For e.g. In Line 201, name or list the metrics/ parameters for the “measured parameters”. Additionally, could show the model equations too.
3. Line 275: Briefly define and fully name “pCO2”
4. Line 404: Section 3.5 Results can be expanded. What important implications are construed when the C assessment results are different for "bulk carbon concentrations" vs. "SOC stocks"?
5. Line 457: The language here can be made more accessible for general and interdisciplinary audience by emphasizing how “robust constrains of dissolution” is meaningful, why the different cations matter and eventually connected to weathering. If such attempts were made to explain the concept in previous sections, it can be reiterated in this discussion section for immediacy and clarity.

Technical corrections:

• Line 347: Table 3 description mentions “Ti” but is not actually listed in the table.
• Line 390: Table 5 description could state or spell out what the three different variables pH, %C and C(t/ha) exactly are in brackets.
• Line 412: “Mean SOC stocks increased from 45.3 t C ha-1 in control plots to 50.3 t C ha-1 in treated plots,”
  • Consider restructuring the sentence to say that treated plots had higher mean SOC stocks than control, not that SOC increased from… to …. This makes it sounds like the control and treated plots are compared to each other as before and after
• Line 457: “these” should be replaced with “the” as it is the first sentence of a new paragraph