Three-Dimensional Ecological Footprint Assessment of Cropland in Typical Grain-Producing Regions Based on Carbon Footprint Improvement

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This study systematically analyzed the cropland carbon footprint and ecological footprint in Hebei Province over the past 40 years, while evaluating the degree of sustainable cropland utilization in various regions of Hebei Province. Overall, this article provided reliable data to support the conclusions and offers the insightful discussion.

1. A passive version and past tense should be used in writing to report data, rewrite abstract and recheck grammar issues throughout the manuscript, avoid any unnecessary error.
2. Readjust the proportions of all figures as well as the font sizes within them to ensure clear presentation for readers, especially in Figures 11 and 14.
3. The text should be rechecked and refined, e.g., Line119-120, “Hebei Province is a key grain-producing region, with a large proportion of cropland, but its per capita cropland (0805hm²/person) is below the national average”, the expression “per capita cropland” could be replaced by “the cropland per capita”. The proportion of the cropland for Hebei should be cited by some other reference(s) about the exact percentage, and similarly, the number of the national cropland per capita level could be showed here for better understanding of the background. All the other place in this manuscript should be quantity if possible.
4. In lines 322 to 330, the description of CO2 has some errors, the upper and lower description.
5. Figure 5, the carbon emissions intensity and absorption intensity across various cities in Hebei Province, the increase or decrease in the exact city should be analyzed with some more reasons.

Author Response

 This study systematically analyzed the cropland carbon footprint and ecological footprint in Hebei Province over the past 40 years, while evaluating the degree of sustainable cropland utilization in various regions of Hebei Province. Overall, this article provided reliable data to support the conclusions and offers the insightful discussion.

We sincerely appreciate the reviewers' positive feedback on our work and their constructive suggestions for improving the manuscript, which have helped us improve the quality of our manuscript. Below, each comment is addressed in detail.

Comments 1: A passive version and past tense should be used in writing to report data, rewrite abstract and recheck grammar issues throughout the manuscript, avoid any unnecessary error. 

Response1: We sincerely thank the reviewer for this valuable suggestion. The manuscript has been thoroughly revised to adhere to the passive voice and past tense when reporting data. The abstract has been rewritten to enhance clarity and conciseness. Additionally, the entire manuscript has been carefully reviewed and edited to correct any grammatical errors and ensure consistency in style and formatting. Specific modifications are highlighted in both the abstract and the main text of the manuscript.

Comments 2: Readjust the proportions of all figures as well as the font sizes within them to ensure clear presentation for readers, especially in Figures 11 and 14. 

Response2: We appreciate the reviewer's attention to the clarity of our figures. In response, we have carefully readjusted the proportions and font sizes of the figures throughout the manuscript to ensure a clear and consistent presentation. Except for Figures 1, 10, and 15, all other drawings have been modified. Special attention has been given to Figures 11 and 14, where we have made significant improvements to enhance readability for the readers. All modified figure titles are highlighted.

Comments 3: The text should be rechecked and refined, e.g., Line119-120, “Hebei Province is a key grain-producing region, with a large proportion of cropland, but its per capita cropland (0805hm²/person) is below the national average”, the expression “per capita cropland” could be replaced by “the cropland per capita”. The proportion of the cropland for Hebei should be cited by some other reference(s) about the exact percentage, and similarly, the number of the national cropland per capita level could be showed here for better understanding of the background. All the other place in this manuscript should be quantity if possible. 

Response3: We appreciate the reviewer's insightful comments and have made the following revisions to address them. These revisions have been highlighted for easy identification.

1. Terminology Adjustment: We have replaced the phrase “per capita cropland” with “the cropland per capita” throughout the manuscript to avoid potential ambiguity and ensure clarity. All the revisions are highlighted.
2. Data and Reference Addition: For the cropland proportion in Hebei Province, we have added relevant data and cited additional references to provide a more accurate and detailed context. Similarly, we have included the national cropland per capita level data to enhance the background understanding. Refer to lines 120-121 for specific modifications.
3. Quantification and Clarity: We have reviewed the entire manuscript to quantify and clarify other relevant data wherever possible, ensuring that the text is precise and informative.  

Comments 4: In lines 322 to 330, the description of CO₂ has some errors, the upper and lower description.

Response4:  We thank the reviewer for pointing out the issues in the description of CO₂ . We have carefully reviewed and corrected the data labeling and description to ensure accuracy and consistency. Additionally, we have conducted a thorough check of the data presentation throughout the manuscript and made necessary adjustments to ensure consistency and clarity in all sections. The changes have been highlighted on page 10, from lines 333 to 341.

Comments 5: Figure 5, the carbon emissions intensity and absorption intensity across various cities in Hebei Province, the increase or decrease in the exact city should be analyzed with some more reasons.

Response5: We appreciate the reviewer's suggestion to provide a more detailed analysis of the carbon emissions and absorption intensity across various cities in Hebei Province. In response, we have added a more comprehensive analysis of the changes in carbon emissions and absorption intensity for the cities. The changes have been highlighted on page 10, from lines 352 to 366.

Reviewer 2 Report

Comments and Suggestions for Authors

See the attached file.

Comments for author File: Comments.pdf

Author Response

We sincerely thank the Reviewer for your insightful feedback and constructive suggestions, which have helped us refine and strengthen our manuscript. In the following, we provide point-by-point responses to their suggestions.

Comments 1: L157. Figure 2 The letter size of legend is too small.

Response1: Thank you for pointing this out. We have adjusted the font size of the legend in Figure 2 to improve readability. The revised figure 2 now clearly displays the legend text, ensuring that all elements are legible. Additionally, considering the suggestions from comments 5-7 regarding figure presentation,we have reviewed and revised other figures in the manuscript to enhance clarity and consistency. The titles of the revised figures have been highlighted for easy identification.

Comments 2: L281, “Conversely, … have decreased” Agricultural mechanization has been highly progressed during the period from 1980 and 2020, and the consumption of fossil fuels and consequent increase of carbon emission must have increased a lot. Why the emission of agricultural machinery has been more or less constant? Clarify this point.

Response2: Thank you for your insightful comment. We have included a concise explanation in the manuscript to address this point, along with the corresponding references and policy measures. Specifically, we highlight that:

1. Technological Advancements and Management Practices: Modern agricultural machinery is more fuel-efficient, reducing emissions per unit of work. Enhanced agricultural practices, such as precision farming, have optimized machinery use and minimized unnecessary fuel consumption.Published in 2023 in the journal "Cogent Food & Agriculture," the article "Agricultural Mechanization, Large-Scale Operation, and Agricultural Carbon Emissions" highlights that agricultural mechanization significantly contributes to agricultural carbon emissions. It notes that the impact of mechanization is sustainable over time. Meanwhile, large-scale agricultural operations have a positive short-term effect on reducing carbon emissions and contribute to lower agricultural emissions in the long run.
2. Policy Measures: Hebei Province has implemented policies to phase out high-emission machinery, contributing to emission reductions.The Hebei Provincial Department of Ecology and Environment’s “2020 Work Plan for the Prevention and Control of Agricultural Machinery Pollution” indicates that the province has phased out 12,000 units of agricultural machinery with emission standards below National II, resulting in significant emission reductions.

These factors collectively help explain why emissions from agricultural machinery have remained relatively stable despite increased mechanization. The interpretations have been incorporated into the revised manuscript. The revised text is located on page 8, lines 289-294.

Comments 3: L292, “fertilizers, pesticides, … 29.42%, and 4.29%” According to Figure 3, agricultural machinery is 4.29% and agricultural irrigation is 29.42%. Clarify this point.

Response3: Thank you for pointing out this error. We apologize for the confusion. The terms "agricultural machinery" and "agricultural irrigation" were indeed reversed in the text. We have now corrected this mistake to accurately reflect the data shown in Figure 3. The revised sentence now correctly states the contributions of agricultural machinery (4.29%) and agricultural irrigation (29.42%) to the overall emissions. The revised text is located on page 9, line 304.

Comments 4: L354, “Laoting and Changli” Many local place names are mentioned including the above. Please prepare a map indicating the location of these places.

Response4: Thank you for your suggestion. We have updated the existing map, figures 6 and 7, to now clearly indicate the locations of Laoting and Changli, as well as other relevant counties mentioned in the text. Considering the vast number of counties in Hebei Province, all prefecture-level cities are labeled in Figure 2. Hebei Province consists of 132 counties, which would look cluttered if all were marked on the map. To ensure clarity, we marked the analyzed counties.

Comments 5: L424, Figure 8 The format of figure is strange. The line connecting the values of 1980 and 2020 does not have any meaning.

Response5: Thank you for your feedback. The lines connecting the values of 1980 and 2020 were intended to show the trend of a specific indicator over time. However, we understand that this may not have been clear, and some data expressions were indeed not sufficiently clear. We have revised Figure 8 to enhance clarity and ensure that the data are meaningfully and accurately represented.

Comments 6: L544, Figure 11 The letter size of legend is too small.

Response6: Thank you for bringing these issues to our attention in light of the figures. We have redrafted the statistical charts for the ecological footprint breadth, ecological footprint depth, and three-dimensional ecological footprint. All text within the figures, including the legends, has been adjusted to an appropriate size in Figure 11.

Comments 7: L580, Figure 12 The letter size of legend is too small.

Response7: Thank you for your comment. In response, we have adjusted the legend size for the spatial distribution maps of the ecological footprint breadth (EF_size), ecological footprint depth (EF_depth), and three-dimensional ecological footprint (EF_3d). We have also adjusted the size and layout of Figure 12 to enhance clarity for readers.

Comments 8: L643, Figure 14 The letter size of legend is too small.

Response8: Thank you for your comment on Figure 14. We have redrafted Figure 14 to better illustrate the sustainable use zoning of cropland in Hebei Province and its 11 prefecture-level cities. Different shapes are now used to represent different zoning types, while different colors indicate different study periods. This approach clarifies the number of sustainable use zones for each region across various time spans.

Comments 9: L743, “However, by 2020, its impact accounted for only 4.29%.” According to Figure 3, it is more than that. Clarify this point.

Response9: Thank you for your meticulous review and for pointing out this discrepancy. We apologize for the discrepancy in the data presentation. This was an error in the manuscript writing process. In response to this comment and in conjunction with comment 3, the accurate value is 29.42%. We have carefully reviewed and revised the data in both the Results and Discussion sections. Additionally, we have verified all other data in the manuscript to ensure consistency and accuracy . The correction has been made on line 793 of section 4.2.

Reviewer 3 Report

Comments and Suggestions for Authors

This paper offers a methodologically solid and well-organised evaluation of cropland sustainability in China's Hebei Province. Using carbon footprint data and a three-dimensional ecological footprint model (EF3d), the authors examine ecological impact and carbon emissions. Their research provides insight into the unsustainable trend of cropland use and lays the groundwork for ecological agriculture practices in the future.

• Ensure EFsize, EFdepth, EF3d, EC, and ED are all clearly defined when first introduced. In some sections, they appear without initial clarification.
• Some figures (e.g., Figures 3–13) are crowded and require clearer legends and more succinct captions. Adding subtitles or summary statements to complex figures will help guide interpretation.
• While the discussion is informative, the article lacks a summary of actionable recommendations for relevant sustainability domains in a dedicated policy implications section.
• A paragraph outlining similarities and differences between Hebei and comparable grain-producing regions globally in terms of cropland sustainability trajectory may enhance global relevance.
• The four-crop focus is understandable, but a brief explanation of why other crops/by-products were not included would help justify the limitations of the scope.

Author Response

This paper offers a methodologically solid and well-organised evaluation of cropland sustainability in China's Hebei Province. Using carbon footprint data and a three-dimensional ecological footprint model (EF_3d), the authors examine ecological impact and carbon emissions. Their research provides insight into the unsustainable trend of cropland use and lays the groundwork for ecological agriculture practices in the future.

 We would like to express our gratitude to the reviewer for their supportive feedback and constructive recommendations, which have allowed us to enhance the manuscript. The following section provides detailed responses to each of their comments.

Comments 1: Ensure EF_size, EF_depth, EF_3d, EC, and ED are all clearly defined when first introduced. In some sections, they appear without initial clarification.

Response1: We appreciate the reviewer's comment and have made the revisions to ensure clarity and proper definition of the terms EF_size, EF_depth, EF_3d, EC, and ED. By providing clear definitions in the methods section and using full names with abbreviations at their first appearance in the text, we have also reviewed the entire manuscript to ensure consistency and clarity in the use of these terms. The changes have been highlighted in the revised manuscript.

Comments 2: Some figures (e.g., Figures 3–13) are crowded and require clearer legends and more succinct captions. Adding subtitles or summary statements to complex figures will help guide interpretation. 

Response2: Thank you for your feedback. We have revised the legends and captions of Figures 1–13 to make them clearer and more concise. Additionally, we have added summary statements to complex figures. We have also reviewed and verified the legends and captions of the other figures to ensure consistency and clarity throughout the manuscript. Except for Figures 1, 10, and 15, all other drawings have been modified. The titles have been highlighted in the revised figures.

Comments 3: While the discussion is informative, the article lacks a summary of actionable recommendations for relevant sustainability domains in a dedicated policy implications section. 

Response3: Thank you for your valuable feedback. In the original manuscript, Section 4.3 analyzed the challenges in cropland ecological security and sustainable use in Hebei Province, along with relevant policy recommendations. However, the previous title was not clear enough and could be easily misunderstood. Therefore, in the revised draft, we have refined the title to better reflect the content. We have also reorganized the content to focus more on the analysis of policy implications, highlighting practical steps that can be taken in different regions to address the issues discussed. The specific modifications are detailed in the highlighted text of Section 4.3 in the discussion.

Comments 4: A paragraph outlining similarities and differences between Hebei and comparable grain-producing regions globally in terms of cropland sustainability trajectory may enhance global relevance.

Response4: Thank you for your insightful suggestion. We have added a new paragraph in the discussion section that outlines the similarities and differences between Hebei Province and other comparable grain-producing regions globally in terms of cropland sustainability trajectory. This addition aims to provide a broader context and enhance the global relevance of our study. Modifications are observed in the second paragraph and the first sentence of the third paragraph in Section 4.1 of the discussion.

Comments 5: The four-crop focus is understandable, but a brief explanation of why other crops/by-products were not included would help justify the limitations of the scope.

Response5: Thank you for your suggestion. We have provided explanations and related references regarding the selection of crops in Section 2.3.2 and the selection of by-products in Section 2.3.1. These sections now include brief justifications for why these crops and by-products were included in the study, aiding in clarifying the scope and limitations of our research.Revised details are in Section 2.3.2 (lines 197–201) and Section 2.3.1 (lines 174–179).