Carbon Footprint of Brazilian Agriculture Based on Field Operations

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Introduction

Lines 27-35: The introduction lacks a clear and concise justification for why it is crucial to study CO2-eq emissions in Brazilian agriculture. While global importance is mentioned, the specific context of Brazil is not sufficiently addressed.

Lines 36-41: Although it is stated that agriculture can act as a carbon sink, there is not enough evidence, or previous studies cited to support this claim specifically in the Brazilian context.

Lines 49-55: The introduction of the proposed methodology is abrupt. It would be beneficial to provide more background on previous studies and how this work differs or improves upon existing methodologies.

 

Methodology

Lines 57-59: The exclusion of transport and post-harvest activities might limit the applicability of the results. It would be beneficial to justify why these processes were excluded and discuss the potential implications of these exclusions.

Lines 85-89: The methodology for calculating emission factors for fertilizers seems adequate, but it does not mention whether differences in fertilizer management practices across Brazil’s producing regions were considered, which could affect the results.

Lines 124-130: Emissions related to chemical use are calculated based on average energy inputs, but there is no discussion on the variability in pesticide application among different crops and regions, which could impact the accuracy of the results.

 

Results

Lines 157-165: The results indicate that direct emissions account for 64% of the total, primarily due to fertilizer and pesticide consumption. However, there is no detailed discussion on the variability among different crops and regions, which is essential for a better understanding of the observed patterns.

Lines 176-181: The comparison between cotton and castor bean systems seems superficial. It would be beneficial to discuss why these crops show significant differences in emissions and what specific factors contribute to these differences.

Figures 2-5: While the figures provide a useful overview, they lack in-depth analysis that explains the trends observed and their relevance to sustainable agricultural practices. It is necessary to suggest to authors that they deliver their figures in better quality formats and they can be better prepared in Python or R.

 

Discussion

Lines 236-241: The discussion of results compared to previous studies is a good start but needs more depth. It would be helpful to explore the reasons behind the observed differences and how this study's results can be used to improve current methodologies.

Lines 264-267: The assertion that digital agriculture can enhance the precision of GHG assessments is valid, but there is no discussion of the barriers to adopting these technologies in Brazil.

Lines 283-285: The conclusion highlights the importance of considering both direct and indirect emissions but does not offer specific recommendations on how farmers can practically reduce their emissions.

Author Response

Dear Reviewer 1, first of all, we would like to thank the carefull evaluation provided to our manuscript. We added comments below the suggestion made as follows below:

Lines 27-35: The introduction lacks a clear and concise justification for why it is crucial to study CO2-eq emissions in Brazilian agriculture. While global importance is mentioned, the specific context of Brazil is not sufficiently addressed.

- We contextualize the problem in a macro view and, in the third paragraph, lines 42 to 48, insert the role of Brazil as one of the main players in world agriculture and how much this sector contributes to emissions national CO2 emissions, thus contextualizing, in the authors' view, the importance of better understanding, in a faster and more general way, the context of CO2 emissions in agriculture in Brazil.

Lines 36-41: Although it is stated that agriculture can act as a carbon sink, there is not enough evidence, or previous studies cited to support this claim specifically in the Brazilian context.

- Studies regarding the possibility of the agricultural sector acting as a CO2 sink were included.

Lines 49-55: The introduction of the proposed methodology is abrupt. It would be beneficial to provide more background on previous studies and how this work differs or improves upon existing methodologies.

- The paragraph has been rewritten to better clarify the suggested points.

 Methodology

Lines 57-59: The exclusion of transport and post-harvest activities might limit the applicability of the results. It would be beneficial to justify why these processes were excluded and discuss the potential implications of these exclusions.

- A justification for excluding the post-harvest and transport stages is inserted immediately after Figure 1 with a comment on their implications.

Lines 85-89: The methodology for calculating emission factors for fertilizers seems adequate, but it does not mention whether differences in fertilizer management practices across Brazil’s producing regions were considered, which could affect the results.

- Differences between regions are integrated into the analysis of operations, which is proposed in the methodology.

Lines 124-130: Emissions related to chemical use are calculated based on average energy inputs, but there is no discussion on the variability in pesticide application among different crops and regions, which could impact the accuracy of the results.

- Differences between regions are integrated into the analysis of operations, which is proposed in the methodology.

Results

Lines 157-165: The results indicate that direct emissions account for 64% of the total, primarily due to fertilizer and pesticide consumption. However, there is no detailed discussion on the variability among different crops and regions, which is essential for a better understanding of the observed patterns.

- An observation about trends of this result was added. The authors would like to say that different regions are not considered due to the observation of different areas of field operations considered here, which already incorporate different regional practices. This model can therefore be applied to different locations to better understand how different emissions are due to different practices.

Lines 176-181: The comparison between cotton and castor bean systems seems superficial. It would be beneficial to discuss why these crops show significant differences in emissions and what specific factors contribute to these differences.

- An observation about the differences were added to the text.

Figures 2-5: While the figures provide a useful overview, they lack in-depth analysis that explains the trends observed and their relevance to sustainable agricultural practices. It is necessary to suggest to authors that they deliver their figures in better quality formats and they can be better prepared in Python or R.

- Figures with better quality and definition are attached

 Discussion

Lines 236-241: The discussion of results compared to previous studies is a good start but needs more depth. It would be helpful to explore the reasons behind the observed differences and how this study's results can be used to improve current methodologies.

- The text was developed in order to better address this topic

Lines 264-267: The assertion that digital agriculture can enhance the precision of GHG assessments is valid, but there is no discussion of the barriers to adopting these technologies in Brazil.

- Current barriers and possible solutions for the adoption of digital agriculture were included in the text.

Lines 283-285: The conclusion highlights the importance of considering both direct and indirect emissions but does not offer specific recommendations on how farmers can practically reduce their emissions.

- Based on a standard measurement that we intend to make possible with the methodology, the most environmentally friendly methods can be replicated among producers interested in expanding markets based on sustainability.

Reviewer 2 Report

Comments and Suggestions for Authors

When finalizing the article, I suggest that the authors consider the following questions:

1. The purpose of the article is specified as "a methodology to estimate CO2-eq emissions, aiming to develop a standardized basis for comparing emissions across various agricultural crops and production systems".   The results are twofold. On the one hand, applied methodology is compared with previous studies.   On the other hand, the results for individual crops and groups of crops are compared. It is not clear from the text which is more important to the authors - the comparison with other authors' results or the comparison between different cultures.

2. The long explanations for the way of calculating the individual indicators need to be presented in another appropriate form. 

3. The results of the table 3show significant differences with other studies. For these reasons, it is difficult to accept the conclusion that "Most of the results are close to other previous studies showing that the methodology is in consonance with what is adopted by other researchers and can be considered valid". 

However, it is not clear to what extent the comparisons account for differences in technology across studies.

Author Response

Dear Reviewer 2, first of all, we would like to thank the valuable evaluation provided. We added comments for all the suggestions made, as follows below:

1. The purpose of the article is specified as "a methodology to estimate CO2-eq emissions, aiming to develop a standardized basis for comparing emissions across various agricultural crops and production systems". The results are twofold. On the one hand, applied methodology is compared with previous studies. On the other hand, the results for individual crops and groups of crops are compared. It is not clear from the text which is more important to the authors - the comparison with other authors' results or the comparison between different cultures.

- Comparison with other studies is a tool to show that the methodology is in line with previous studies and appears to cover different types of crops and agricultural practices. Both results are important given that one analyzes emissions among themselves with the proposed methodology and the second, comparing with the studies, shows a consonance with different methodologies, standardizing them.

2. The long explanations for the way of calculating the individual indicators need to be presented in another appropriate form.

- After the explanations there is a table (Table 3), the authors emphasize that a detailed description of how calculations and values ​​are obtained are an essential part of the methodology.

Reviewer 3 Report

Comments and Suggestions for Authors

 The topic is interesting and the article is within the scope of the journal, but it needs minor revisions.

 

 

Comments for author File: Comments.pdf

Comments on the Quality of English Language

Author Response

Dear Reviewer 3, first of all, we would like to thank the valuable evaluation provided. We added comments for all the suggestions made, as follows below:

3. The results of the table 3show significant differences with other studies. For these reasons, it is difficult to accept the conclusion that "Most of the results are close to other previous studies showing that the methodology is in consonance with what is adopted by other researchers and can be considered valid".

- The sentence was rewritten highlighting the reason for the differences between the results.

However, it is not clear to what extent the comparisons account for differences in technology across studies.

- The text was revised to more clearly clarify doubts about the comparison with previous studies.

 

Reviewer 3

Comments and corrections suggested in the PDF file have been inserted into the text

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Analysis of document changes with TrackChange

Line 14-24: The summary now includes more precise data and greater clarity in describing the methodology and results.

Line 28-63: Some sentences have been reworded for clarity. Definitions and context of GHG emissions have been improved.

Line 64-174: Detailed descriptions of emission factors and methodologies have been added. Clarifications on data sources and calculations are provided.

Line 175-261: More detailed explanations of the results, including additional data points and comparisons between different cropping systems.

Line 262-312: The discussion now includes a more detailed analysis of the implications of the findings. References to specific data points from the results are included to support the discussion.

Line 314-332: The conclusion is more concise and directly addresses the significance of the findings. The emphasis on implications for policy and sustainable practices is stronger. The conclusion effectively summarizes the contributions of the study and underscores the importance of the findings for future research and policy formulation. The call for collaboration among stakeholders is well articulated.

 

General remarks

The changes made throughout the paper improve clarity and provide more detailed explanations of methodologies and results. This improves the overall readability and impact of the article.

The additional details on the emission factors and their calculations strengthen the methodological basis of the study. This makes the findings more reliable and credible.

The revisions help to create a better flow between the introduction, methodology, results, and discussion sections. This consistency makes it easier for readers to follow the narrative of the study and understand its significance.

 

Recommendations

Accept with minor revisions. The changes made to the trackchange document have substantially improved the document, addressing previous weaknesses and improving the overall quality and impact of the study.

 

Personal comment

The graphics are depressing.

Author Response

Dear reviewer 1,

Thank you for your valuable contribution. We hope the changes made fulfilled the expectiations on this manuscript.

Reviewer 2 Report

Comments and Suggestions for Authors

The additions made and the new edition have improved the quality of the material.

I wish success and many citations to the article.

Author Response

Dear Reviewer 2.

Introduction has been reviewed for improvement on its presentation. We thank you for your valuable contribution.