In the present manuscript, Hazera and co-authors present an extensive, well-characterized dataset of 173 soil samples and 9 reference materials analyzed with the established Rock-Eval method. They propose an adjustment to the standard temperature windows of this method and convincingly show that reducing the maximum pyrolysis temperature from 650°C down to 520°C can help reduce overlap between low-temperature carbonate phases and organic carbon signals at the end of pyrolysis and remove the need for post-hoc corrections which can induce bias. They show that most characteristic indices calculated using established protocols remain statistically comparable between the two methods and deviations are predictable. The only drawback of the adjusted method appears to be larger uncertainty at higher SOC values (upward of ~4 wt%), which represents a potentially significant limitation and requires further exploration in future work.

Overall, I commend the authors on a very clearly written and structured technical note which cites an extensive amount of current literature and firmly roots its claims in both previous work and statistical analysis. Potential problems of inter-lab comparability are well addressed by measuring common standards as well as a subset of samples across labs.

However, a few points require clarification and are listed below:

L47: Consider changing to "consists of"

L55-56: Add the mineral names calcite and dolomite after the chemical descriptions, as this is how you will refer to them throughout the rest of the text

L61 (and many more occasions): Change the hyphen ("-") to an en-dash (“–“) when giving ranges

L68-69: Change to: SIC "generally" decomposes[...], as you will later state how not all inorganic carbon is more temperature resistant than all organic carbon.

L72: Spell out Mineral Carbon (MINC) at least once

L100-103: At 520°C the decomposition of (admittedly pretty rare) siderite starts, so the present method does not really rule out an artifact from this. It should be briefly mentioned later in the discussion. As it is one of the central arguments of this procedure, I suggest being very precise around it.

L122-123: You mention the mineralogy of the samples. Table S1 is not (yet?) available under the doi, but I wonder if you quantified siderite or other carbonate content? It would help to add half a sentence about this, as the reader just learned (L100) that this is something to look out for.

L137: If you re-introduce the abbreviations, also reintroduce Elemental Analyzer (EA)

L138-139 and Table 2: Organic C from the samples was removed by heating to 550°C, although we learned earlier that even calcite starts to break down at this temperature. This raises the suspicion of a slight circularity in the argumentation. I assume a good match between TC measured by EA of untreated sample and SOC(HCl)+ SIC(550°) measured from the two treatments shows this was not a big problem, but maybe say that explicitly? The paper really focuses on these thermal boundary regions.

Table 2: What is the difference between "acidification" and "small-scale acidification"? Was a smaller quantity of acid or material used? Consider removing this distinction if not relevant.

L151-152: Consider rephrasing/combining the two sentences to make clear what was measured (TOC and MINC) and what was estimated based on the measurements (TC, SOC, SIC).

L158: Consider giving the TC range of samples used in the inter-lab comparison, similar to giving the range of standards used earlier.

L165: How was the 5-minute hold temperature determined? If no tests were conducted, cite a reference where this was shown.

L188 (and multiple occasions): Consider referring to the century-stable carbon as C_S with the S in subscript for readability

L220-221: Consider removing the dedicated sample numbers for the samples analyzed with PARTY_SOC, as we did not see sample numbers before, e.g., for the inter-lab samples. You can indicate the samples in Table S1.

L250-251: I assume the 182 samples are the 173 soils plus the 9 standards, but the phrasing makes it a bit ambigous if it's two sets of samples. Consider clarifying

L277-279: The performance of the PYRO520 method seems to be considerably worse for samples with more than 4 wt% OC, which is a value regularly exceeded in real-world samples. Maybe you can spend a few sentences on the reasons and consequences for the applicability of the modified procedure.

L339: Consider rephrasing the sentence and maybe talk about the "absence" of the 520 to 550°C temperature range instead of a signal reduction, as these temperatures were never realized in PYRO520.

L405 onward: In my opinion, another one or two sentences on ways forward and the general implications of the technical note are needed. The data is presented nicely and the most important results are repeated in the conclusion. But is this method now ready to be applied for low-TOC soil samples, or should higher-TOC samples, or a refinement of the HI, OIRE6 indices etc. be the next priority?

This is a very nice and timely study. The idea to lower the pyrolysis temperature to 520°C is simple but brilliant, effectively solving the long-standing problem of signal overlap between SOC and SIC at the end of the standard pyrolysis. The manuscript is well-written, the dataset is extensive, and the results are convincing. This work has significant practical implications for improving Rock-Eval standard procedures.

However, a few points require clarification and are listed below:

Major Comments:

Did you test other temperatures (e.g., 515°C, 525°C)? A graph showing the SIC signal (from the oxidation phase) versus final pyrolysis temperature for a few samples would be very helpful to prove that 520°C is the optimal cutoff. Please provide a more detailed discussion on the decomposition temperatures of different carbonate minerals (calcite, dolomite, siderite) to better explain why 520°C is the chosen "practical compromise."

The type of carbonate (e.g., calcite vs. dolomite) and its association with organic matter could affect its decomposition temperature. I recommend adding mineralogical data (e.g., XRD analysis) for a subset of samples to characterize the dominant carbonate phases.

Please discuss if the diagenetic carbonates in rocks behaved differently from the pedogenic carbonates in soils in your analyses. This will help clarify the applicability of your method to different sample types.

Minor Comments:

The larger errors for samples with SOC ≥ 40 g C kg⁻¹ are noted. Please add a brief hypothesis for this observation (e.g., related to more refractory organic compounds like pyrogenic carbon?).

The correlation between Cs650 and Cs520 is excellent. A short comment on the model's transferability to the new PYRO520 thermal program would be useful for readers.