Novel Methodology for the Assessment of Organic Carbon Stocks in German Arable Soils
Round 1
Reviewer 1 Report
The manuscript entitled “Soil carbon stock assessment” represents a methodology developed to evaluate agricultural management regarding the carbon input to soil and the amount of carbon stored in the soil to deduce a model further to mimic the relation between carbon flux and SOC stock. This well-written manuscript provides more recent advances with a particular focus on closing the gap using the VDLUFA method.
Some of a few formal comments on the manuscript as following indicated:
1. The title is not sufficient to cover the research objective. Recommending revising the title to “Optimized method for Soil carbon stock assessment.”
2. the keywords are inaccurate and should be more than five.
3. Detailed legend should be provided in Figures 2, 3, and 5.
4. Some flaws were identified primarily in the format, particularly for citation and references.
Author Response
Reply to the comments of reviewers
First of all, we want to thank both reviewers for the effort they spent to provide valuable hints to further improve our manuscript. In the following, we repeat the comments and add our reply in Italics. Additionally, we added line numbers that relate to the now revised manuscript.
Reviewer 1
The manuscript entitled “Soil carbon stock assessment” represents a methodology developed to evaluate agricultural management regarding the carbon input to soil and the amount of carbon stored in the soil to deduce a model further to mimic the relation between carbon flux and SOC stock. This well-written manuscript provides more recent advances with a particular focus on closing the gap using the VDLUFA method.
Thank you very much for this kind comment
Some of a few formal comments on the manuscript as following indicated:
The title is not sufficient to cover the research objective. Recommending revising the title to “Optimized method for Soil carbon stock assessment.”
Thank you for this suggestion, We have changed the title considering also the suggestions of reviewer 2
the keywords are inaccurate and should be more than five.
We followed your advice and included more keywords without doubling items that are already used within the title
Detailed legend should be provided in Figures 2, 3, and 5.
We have changed Figures 2 & 3 and added further information within the captions of all three figures
Some flaws were identified primarily in the format, particularly for citation and references.
Thank you for this hint; we corrected the wrong citation
Reviewer 2 Report
The study, titled “Soil carbon stock assessment”, developed a methodology for the assessment of the carbon input to soil and the amount of carbon stored in soil in terms of different agricultural managements. The general applicability and the plausibility of the assessment approach were checked for selected treatments at long-term field experimental sites and on a regional scale for arable soils. Overall, the topic of this manuscript is suitable for the journal and of broad international interest. The overall structure of the manuscript is sound, data are analyzed and presented beautifully, and the manuscript is well written. However, there are some major concerns that need to be addressed before further consideration.
Major comments:
Title: This title is too general to demonstrate the main findings or progress of the work, and it does not provide pertinent and useful information about this study. Since this is a case study to assess the soil organic carbon stock with agricultural management in Germany, I suggest that the title could be changed into “Novel methodology for the assessment of organic carbon stock in German arable soils”.
Abstract: the first three sentences of the abstract looks quite disconnected with the topic of the manuscript. I suggest that the authors state why the soil carbon stock assessment is important and specify the research gap clearly as well.
Introduction: since the research topic of this manuscript is to discuss the soil carbon stock assessment in German arable soils, it is better to spend more writing space to show why soil carbon stock assessment are important, and the current progress in SOC stock of German arable soils and the relevance of this study. Second, the literature review didn’t give any information about the existing assessment methods, and their advantages or disadvantages. Besides, references is not very coherent and too few either in the introduction or in the discussion sections. It is better to reorganize it to make it more relevant and focused on the scientific problems of this study, or to make the knowledge gap to be addressed in this study in a clear way. In addition, hypotheses are lacked in the last paragraph of the Introduction. Instead, the current ending of the Introduction section appears to be the proposed solutions to the study. Proper citation of references should be considered in the whole draft. The format of references was also inconsistent in the text.
The dataset with a long time series is of significant values for the modeling of SOC turnover. However, the organization and interpretation of the present work is very poor. More discussions are necessary for the comparison of the current results to the similar ones, as well as the justification of the method. The conclusion seems to be the arguing words or debates on the results.
Minor comments:
Abstract:
Line 12 give the full name of SOM as this is the first time as it appears in the manuscript.
Line 19-20 It is totally unclear about the meaning. Please improve this sentence and make it clear.
The value and necessity of the study was not clearly presented in this section.
Introduction
Line 27 the citation format here is inconsistent with the ones elsewhere in the manuscript, please double check and make the citation format uniform.
Material and methods
Line 82 please give the full name of FYM as it appears firstly in the manuscript.
Line 154 References should be at the end of this sentence.
Discussion
I noticed that the authors only presented the results without discussing the reasons or mechanisms, and didn’t compare the results with other studies. In addition, almost no literature was cited in the Results and Discussion, more related papers need to be cited in this manuscript to improve the quality of this work.
Line 206-216 these are methods description for analyzing the effect of FOM input on C stock, which should be included in the section of Material and methods, insead of the Results and Discussion.
Line 283 What does it mean for “SOC diversity”?
Conclusion
The current main conclusions are not effective and convincing enough. For instance, Line 333-335, Line 342-343, these sentences is not related to the topic of this paper and does not provide more information in terms of this manuscript's unique contribution.
The last paragraph is not a conclusion, which should be included in the Discussion section.
Author Response
Reply to the comments of reviewers
First of all, we want to thank both reviewers for the effort they spent to provide valuable hints to further improve our manuscript. In the following, we repeat the comments and add our reply in Italics. Additionally, we added line numbers that relate to the now revised manuscript.
Reviewer 2
The study, titled “Soil carbon stock assessment”, developed a methodology for the assessment of the carbon input to soil and the amount of carbon stored in soil in terms of different agricultural managements. The general applicability and the plausibility of the assessment approach were checked for selected treatments at long-term field experimental sites and on a regional scale for arable soils. Overall, the topic of this manuscript is suitable for the journal and of broad international interest. The overall structure of the manuscript is sound, data are analyzed and presented beautifully, and the manuscript is well written.
Thank you for this encouraging feedback.
However, there are some major concerns that need to be addressed before further consideration.
Major comments:
Title: This title is too general to demonstrate the main findings or progress of the work, and it does not provide pertinent and useful information about this study. Since this is a case study to assess the soil organic carbon stock with agricultural management in Germany, I suggest that the title could be changed into
“Novel methodology for the assessment of organic carbon stock in German arable soils”.
We thank you for this suggestion and changed the title.
Abstract: the first three sentences of the abstract looks quite disconnected with the topic of the manuscript. I suggest that the authors state why the soil carbon stock assessment is important and specify the research gap clearly as well.
We improved the text at some places and think that now the abstract gives a good overview about the paper (lines 10-12,14, 20-23).
Introduction: since the research topic of this manuscript is to discuss the soil carbon stock assessment in German arable soils, it is better to spend more writing space to show why soil carbon stock assessment are important, and the current progress in SOC stock of German arable soils and the relevance of this study.
We followed this suggestion and changed/added text (lines 33-41, 82-88).
Second, the literature review didn’t give any information about the existing assessment methods, and their advantages or disadvantages. Besides, references is not very coherent and too few either in the introduction or in the discussion sections. It is better to reorganize it to make it more relevant and focused on the scientific problems of this study, or to make the knowledge gap to be addressed in this study in a clear way.
Thank you for this hint, several references about SOC stock studies were added.
In addition, hypotheses are lacked in the last paragraph of the Introduction. Instead, the current ending of the Introduction section appears to be the proposed solutions to the study.
Paragraph with hypotheses was added (lines 82-88).
Proper citation of references should be considered in the whole draft. The format of references was also inconsistent in the text.
We added further references added and corrected wrong format.
The dataset with a long time series is of significant values for the modeling of SOC turnover. However, the organization and interpretation of the present work is very poor. More discussions are necessary for the comparison of the current results to the similar ones, as well as the justification of the method. The conclusion seems to be the arguing words or debates on the results.
We improved discussion and conclusion according to this suggestion.
Minor comments:
Abstract
Line 12 give the full name of SOM as this is the first time as it appears in the manuscript.
Text was changed.
Line 19-20 It is totally unclear about the meaning. Please improve this sentence and make it clear.
Text was changed.
The value and necessity of the study was not clearly presented in this section.
Some changes were applied according to this suggestion (see above).
Introduction
Line 27 the citation format here is inconsistent with the ones elsewhere in the manuscript, please double check and make the citation format uniform.
Citation format is changed now.
Material and methods
Line 82 please give the full name of FYM as it appears firstly in the manuscript.
Text was changed.
Line 154 References should be at the end of this sentence.
Missing references ?? We consider this statement as common knowledge.
Discussion
I noticed that the authors only presented the results without discussing the reasons or mechanisms, and didn’t compare the results with other studies. In addition, almost no literature was cited in the Results and Discussion, more related papers need to be cited in this manuscript to improve the quality of this work.
The introduction contains now some more hints to works about SOC stocks. We presented here a methodology to assess SOC stocks similar to the VDLUFA humus balance method. To our knowledge, there is no other study available addressing this topic, but we added some text to show the necessity to link qualitative and quantitative assessment approaches.
Line 206-216 these are methods description for analyzing the effect of FOM input on C stock, which should be included in the section of Material and methods, insead of the Results and Discussion.
The first sentence of the above-mentioned paragraph is important for the understanding of the below described results – it is an introduction to the corresponding part of the Result’s section. Therefore, we repeated the basic information at this place. Now, we inserted a reference to the M&M section 2.3.
Beginning with the second sentence of the above-mentioned paragraph, we clearly describe the corresponding results of applying different time scales (calendar and BAT) on the dynamics of C stock changes.
Line 283 What does it mean for “SOC diversity”?
Text is changed into ‘a wide range of SOC levels’.
Conclusion
The current main conclusions are not effective and convincing enough. For instance, Line 333-335, Line 342-343, these sentences is not related to the topic of this paper and does not provide more information in terms of this manuscript's unique contribution.
333-335. Here, we disagree with the reviewer.
We want to start the conclusions with this statement to emphasize the gap that we think have closed.
342-342:
We changed the text to better express our intentions (lines 385-387) and shifted a paragraph to chapter 3.4 (lines 363 ff):
The last paragraph is not a conclusion, which should be included in the Discussion section.
Text changed shifting a paragraph to chapter 3.4 (lines 363 ff):
Author Response File: 
Author Response.docx
