Review Reports

Round 1

Reviewer 1 Report

Soil property rather than climate controls subsoil carbon turnover time in forest ecosystems across China

This paper aim to investigate subsoil τ and its influence factors in forest ecosystems across China by compiling a dataset with 630 observations using structural equation model. SEM offered a new result that the soil property, rather than climate, was the most important factor in affecting subsoil τ. This finding challenged our previous understanding that climate was the most important factor driving subsoil C dynamics, but dominant drivers varied with climate zones. It is important to recognize different dominant factors in predicting subsoil C dynamics across climate zones would improve our understanding and reduce uncertainties in subsoil C dynamics in biogeochemical models under ongoing climate change. However, the paper should be improved further if accepted. I think the paper should be reconsidered with major revisions. The detailed suggestions are as follows:

1.    Line 48-51, lack of logicalrelations.

2.    Line 51-52, the references should be listed.

3.    Line 56-80, the logicalrelations should be clear, the research questions and objectives confuse me now. The summaries of previous studies are empty.

4.    Line 239-371, the discussion part is terrible. The part should explain the reasons of results. It needs to be rewritten.

Author Response

Response to Reviewer 1 Comments

Soil property rather than climate controls subsoil carbon turnover time in forest ecosystems across China

This paper aim to investigate subsoil τ and its influence factors in forest ecosystems across China by compiling a dataset with 630 observations using structural equation model. SEM offered a new result that the soil property, rather than climate, was the most important factor in affecting subsoil τ. This finding challenged our previous understanding that climate was the most important factor driving subsoil C dynamics, but dominant drivers varied with climate zones. It is important to recognize different dominant factors in predicting subsoil C dynamics across climate zones would improve our understanding and reduce uncertainties in subsoil C dynamics in biogeochemical models under ongoing climate change. However, the paper should be improved further if accepted. I think the paper should be reconsidered with major revisions. The detailed suggestions are as follows:

Point 1: Line 48-51, lack of logicalrelations.

Response 1: Thank you. We recapped the passage and redescribed it

Point 2: Line 51-52, the references should be listed.’

Response 2: We deleted the description of the passage and added some new sentences.

Point 3: Line 56-80, the logicalrelations should be clear, the research questions and objectives confuse me now. The summaries of previous studies are empty.

Response 3: We are very sorry for the confusion caused to you. We have redescribed these three paragraphs and clearly expressed our research objectives.The description of previous studies has also been revised.I hope you will be satisfied with the revised manuscript.

Point 4: Line 239-371, the discussion part is terrible. The part should explain the reasons of results. It needs to be rewritten.

Response 4: Thank you very much for your question. We have drastically revised the entire discussion section.In addition, parts 4.2 to 4.5 are put together for discussion in order to make the discussion on climate, vegetation and soil more integrated with our research results.

Author Response File: Author Response.docx

Reviewer 2 Report

The MS “Soil property rather than climate controls subsoil carbon turnover time in forest ecosystems across China” by Yu et al. estimated the subsoil carbon turnover time at regional scales and using meta-analysis and also determines the potential role of some influencing factors. The study presents a good experimental design and a good statistic elaboration. The data are well presented. However, the manuscript reveals some shortcomings that must be resolved before it can be published. 

General and specific comments

The MS has several typos and needs to be checked with attention.

Abstract: Add some data to illustrate your main results.

Line 24, subsoil τ differed significantly with forest types, How different?

Line 46, SOC, first occurrence should be defined.

Line 85, Why only 2001-2014? What about the literature from 2014-2022?

L83, It should be clear which databases you use.

L83, Where are your search keywords?

L85, the criteria should more specific.

L107, The abbreviations in Figure 1 should be stated in the caption.

L237, delete ** p < 0.01

L230, Figure 4 is too vague. I suggest deleting the background.

L230, The total effect of SEM should be presented in the text.

4.2 to 4.5 section should be put together.

Conclusions are badly written and need to answer (at least in part) the questions made by the authors in the aim of the paper (lines 77-80).

Author Response

Response to Reviewer 2 Comments

The MS “Soil property rather than climate controls subsoil carbon turnover time in forest ecosystems across China” by Yu et al. estimated the subsoil carbon turnover time at regional scales and using meta-analysis and also determines the potential role of some influencing factors. The study presents a good experimental design and a good statistic elaboration. The data are well presented. However, the manuscript reveals some shortcomings that must be resolved before it can be published.

General and specific comments

The MS has several typos and needs to be checked with attention.

Response: We have gone over the manuscript and corrected the incorrect sentences.

Point 1: Abstract: Add some data to illustrate your main results.

Response 1: Thanks. Done as suggested. We added the subsoil τ of different stand types and SEM analysis results.

Point 2: Line 24, subsoil τ differed significantly with forest types, How different?

Response 2: We analyzed the subsoil τ of stand type by one-way analysis of variance (ANOVA), and the results showed that the subsoil τ of different stands is significantly different (p=0.01). The results show that the τ is the slowest in deciduous broad-leaved forest and the fastest in evergreen broad-leaved forest（Table A1）.

Point 3: Line 46, SOC, first occurrence should be defined.

Response 3: Done as suggested.

Point 4: Line 85, Why only 2001-2014? What about the literature from 2014-2022?

Response 4: Thank the reviewer for your valuable comments. The carbon storage data of China's terrestrial ecosystems used in this study were mainly from published literature data. A total of 630 forest sample sites in the publicly published data set met our research needs. Of course, we also looked for whether there were publicly published data sets on carbon storage for 2014-2022. Unfortunately, there are only a few publicly published carbon storage data sets for 2014-2022, and the subsoil depth does not meet our research needs. We studied the carbon turnover of the subsoil from 0.2-1m. Therefore, the deadline of our study is 2014.

Point 5: L83, It should be clear which databases you use.

Response 5: Done as suggested.

Point 6: L83, Where are your search keywords?

Response 6: Thank you very much for your question, we have added specific search keywords.

Point 7: L85, the criteria should more specific.

Response 7: Thanks, we have a more specific description of the three criteria.

Point 8: L107, The abbreviations in Figure 1 should be stated in the caption.

Response 8: Done as suggested.

Point 9: L237, delete ** p < 0.01

Response 9: Done as suggested.

Point 10: L230, Figure 4 is too vague. I suggest deleting the background.

Response 10: Thanks. Done as suggested.

Point 11: L230, The total effect of SEM should be presented in the text.

Response 11: We redescribed the results of SEM.

Point 12: 4.2 to 4.5 section should be put together.

Response 12: Thank you very much for your valuable advice. In our revision process, we also found that it is more reasonable to set the results of climate, vegetation, soil and SEM into one chapter, because the results of SEM will also reveal which environmental variables (climate, soil and vegetation) are more important. We have rewritten the discussion section according to your comments.

Point 13: Conclusions are badly written and need to answer (at least in part) the questions made by the authors in the aim of the paper (lines 77-80).

Response 13: Thanks. We supplemented and modified the conclusions according to the research objectives.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Soil property rather than climate controls subsoil carbon turnover time in forest ecosystems across China

The paper had been improved a lot. However, there are still some questions. I think the paper should be accepted with minor revisions. The detailed suggestions are as follows:

Point 1: Line 101-104, the research objective should be added.

Point 2: Line 325, “vegetation” change to “Vegetation”

Point 3: Line 387, “factor” change to “factors”

Point 4: Line 416, “influenced” change to “influencing”

Author Response

Soil property rather than climate controls subsoil carbon turnover time in forest ecosystems across China

The paper had been improved a lot. However, there are still some questions. I think the paper should be accepted with minor revisions. The detailed suggestions are as follows:

Point 1: Line 101-104, the research objective should be added.

Response 1: We are very sorry that you think our study lacks research objectives due to our unclear description of research objectives. We have revised this paragraph. The research objectives of this paper include three aspects. One is to estimate and compare the subsoil τ of different climate, forest types, forest ages and forest origins in Chinese forest ecosystem. The other is to analyze the influence of climate, vegetation and soil factors on the subsoil τ. The last one is to explore the main environmental factors affecting the subsoil τ.

Point 2: Line 325, “vegetation” change to “Vegetation”

Response 2: Thanks. Done as suggested.

Point 3: Line 387, “factor” change to “factors”

Response 3: Done as suggested.

Point 4: Line 416, “influenced” change to “influencing”

Response 4: Done as suggested.

 

We would like to express our great thanks again to the reviewers for your valuable suggestion and comments.

Author Response File: Author Response.docx