The manuscript describes a modelling study to analyse historical and future fluxes of soil organic carbon and its sequestration potential on global croplands. The authors describe in detail the various simulation steps to calculate historical SOC stocks and projected SOC changes under different management and climate scenarios. The estimated SOC stocks are compared to previous estimates. Model results are sensitive to assumptions about different amounts of residue remaining in the field, while different tillage and climate change scenarios have a small impact on estimated SOC stocks. The authors reach the conclusion that carbon sequestration potential as a climate change mitigation strategy is low and that SOC stocks are mainly declining by the end of the century. This article is of high scientific value and I recommend it for publication without any substantial revision.

In general, this manuscript is well written and simple enough to understand. I have noticed some model input values whose origin I do not understand. It would improve the understanding of the model if the following were more clearly explained

Line 82 -83

What is the 40/60 ratio based on that determines how much C is released into the soil or emitted into the atmosphere?

Line 87

Similar to above, where does the 50% come from?

Line  156

What does tillage intensity set to 0.9 mean?

Line 300

“a third” instead of 1/3

Finally, spelling out the management scenarios in the text would improve readability rather than using the abbreviations (T_NR, NT_NR, etc.), although I understand that this can be handled according to personal preference. In addition, spelling out the management scenarios in Table 3 would save time for the reader who may not have the abbreviations in mind.

This manuscript used a processed-based model to simulate the cropland SOC stocks change historically and in the future under different climate scenarios. The historical simulations of global and cropland SOC stocks are comparable with previous studies. The future projections with various agricultural practices show that residue management has a greater impact on SOC stocks as compared to tillage.  This study provides important insight on preferred management to maximize cropland SOC storage under climate change. My main concern is that the future simulations did not include the impact of irrigation. Besides increasing temperature and CO2, climate change also has a strong impact on regional precipitation, in turn, the soil moisture and vapor pressure deficit. Studies have shown that soil moisture has a strong impact on the global carbon cycle (e.g. Humphrey, V., et al. (2021). "Soil moisture-atmosphere feedback dominates land carbon uptake variability." Nature 592(7852): 65-69.). In this study, the authors only mentioned croplands were separated into the irrigated and rain-fed areas in the historical simulations (lines 122-124). Did the future simulations use the same irrigation management as the year 2015? Can the authors at least clarify their method of determination of the irrigated and rain-fed areas and add discussion on the impact of irrigation practice and its interaction with other managements on cropland SOC stocks. I look forward to reading a revised version of this manuscript. 

Specific comments:

1. The “SOC sequestration potential” in the title seems to be misleading. Sequestration indicates SOC accumulation even under climate change as long as we use proper management. However, the results of this study show that the global SOC stocks decrease under all climate scenarios and management. I think using something like “SOC stock dynamics” is more appropriate. 

2. The impact of various agriculture practices, such as residue management, tilling, and irrigation should be described in the introduction to set up for the results and discussion. 

3. Line 115: the potential natural vegetation data need a reference. 

4. Line 237-238: this description of h_dLU_area05 is quite confusing. Can the authors describe this scenario in the method?

5. Line 240 - 243: the h_dLU_area05 scenario described here is more clear, but it still should be described in the method and be listed as one of the scenarios in Table 1, because it is related to the main conclusion that cropland SOC stock decrease over history. 

6. Line 248 - 249: this sentence needs some editing. Did the authors mean the calculation of the actual decrease in SOC stocks from LUC considered areas that were converted to cropland at any time over the entire period (1700-2018)? 

7. Line 272: what lead to the sudden jump of SOC, turnover rate, and litterfall between 2000 and 2005 in all management scenarios? 

8. Line 379-382: the mechanism of SOC forming should be better described and referenced here. The number of residues that can be retained on cropland also depends on both the quantity and quality of residues. The priming effect is not always positive. Since the authors discussed the compensating effect of higher productivity and turnover rates in the following paragraph, the effect of temperature on organic matter decomposition should be described here to set up the following discussion.