Effects of Agricultural Production Patterns on Surface Water Quality in Central China’s Irrigation Districts: A Case Study of the Four Lakes Basin

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This article focuses on the Four Lakes Basin in the Jianghan Plain to investigate the influence of agricultural production patterns on surface water quality in central China’s irrigation districts. The topic aligns with China's national needs for the Yangtze River Protection Strategy and the control of agricultural non-point source pollution. It comprehensively employs a variety of data and methods, conducting a relatively in-depth exploration of the spatiotemporal variations in total nitrogen (TN) and total phosphorus (TP) loads in the basin, as well as their response relationships with water quality evolution. However, the article still has obvious shortcomings in terms of methodological rigor, depth of result interpretation, and writing quality, requiring substantial revisions. The specific questions include the following:

• The article employs a large volume of data for analysis, yet the introduction of the data is insufficiently detailed. For instance, regarding rainfall data, there is no elaborate explanation of whether it is point-specific data or data with a certain spatial resolution. This deficiency easily gives rise to doubts about the scientific validity of the calculations. Therefore, it should provide a detailed account of the data sources.
• There are still certain deficiencies in the research methods. Particularly for the entire basin, although the Export Coefficient Model is used to estimate pollution loads, no validation has been conducted. Whether the pollution load of the entire basin is simply the average of the loads of each sub-segment remains open to discussion. If there are on-site observation data from rice-crayfish fields, it is recommended to supplement with measured flux data of total nitrogen (TN) and total phosphorus (TP) from several cases to further enhance the credibility of the research.
• Is Section 3.4 necessary? Although it analyzes intra-annual variations, it provides limited support for the overall analysis of the paper. It is recommended to consider whether this section should be removed.
• It is suggested that some statements in the article should be toned down. For example, the paper claims that the deterioration of Honghu Lake's water quality is mainly driven by "internal nutrient release and extreme climates", yet there is no corresponding supporting data in the article. Additionally, the analysis of influencing factors is limited to correlation analysis. Therefore, it is recommended to weaken the relevant statements.
• There are also some obvious issues in the article. For example, after Section 3.4, the section number incorrectly shifts to 2.5. Additionally, after the abbreviations for total nitrogen (TN) and total phosphorus (TP) are first introduced, their full names are repeatedly used in subsequent parts of the article(which is not in line with academic writing conventions).

 

Author Response

Comments 1:

The article employs a large volume of data for analysis, yet the introduction of the data is insufficiently detailed. For instance, regarding rainfall data, there is no elaborate explanation of whether it is point-specific data or data with a certain spatial resolution. This deficiency easily gives rise to doubts about the scientific validity of the calculations. Therefore, it should provide a detailed account of the data sources.

Response 1:

Thank you for highlighting this point. We fully agree with your comment. The sources of all data have been elaborated in detail, as shown in Lines 169-173 of the paper.

Comments 2:

There are still certain deficiencies in the research methods. Particularly for the entire basin, although the Export Coefficient Model is used to estimate pollution loads, no validation has been conducted. Whether the pollution load of the entire basin is simply the average of the loads of each sub-segment remains open to discussion. If there are on-site observation data from rice-crayfish fields, it is recommended to supplement with measured flux data of total nitrogen (TN) and total phosphorus (TP) from several cases to further enhance the credibility of the research.

Response 2:

Thank you for highlighting this point. We fully agree with your comment. Field observation data have been supplemented, and the average value of this data and relevant research data within the region has been used as the nitrogen and phosphorus (N/P) export coefficients.

Comments 3:

Is Section 3.4 necessary? Although it analyzes intra-annual variations, it provides limited support for the overall analysis of the paper. It is recommended to consider whether this section should be removed.

Response 3:

Thank you for highlighting this point. It is recommended to retain this part. The flood season is a critical period for the external nitrogen and phosphorus (N/P) input to Honghu Lake each year.

Comments 4:

It is suggested that some statements in the article should be toned down. For example, the paper claims that the deterioration of Honghu Lake's water quality is mainly driven by "internal nutrient release and extreme climates", yet there is no corresponding supporting data in the article. Additionally, the analysis of influencing factors is limited to correlation analysis. Therefore, it is recommended to weaken the relevant statements.

Response 4:

Thank you for highlighting this point. In accordance with the comments from other reviewers, the "Results" and "Discussion" sections have been written as separate parts . Corresponding supporting data has been added(lines 478-481), and the presentation of relevant conclusions has been softened.

Comments 5:

There are also some obvious issues in the article. For example, after Section 3.4, the section number incorrectly shifts to 2.5. Additionally, after the abbreviations for total nitrogen (TN) and total phosphorus (TP) are first introduced, their full names are repeatedly used in subsequent parts of the article(which is not in line with academic writing conventions).

Response 4:

Thank you for highlighting this point. Issues related to abbreviation conventions similar to those in the text have been revised.

Reviewer 2 Report

Comments and Suggestions for Authors

Dear Authors,

Water pollution is a serious threat, and significant efforts are paid to mitigate it. The efficacy of such efforts is interesting to examine. The reviewed manuscript deals with water pollution in China related to agriculture. Indeed, this study is of international importance and related to sustainability – thus, it matches the scope of “Sustainability”. The study itself is perfect, and it is communicated clearly. The objective is well stated, and the materials and methods are explained sufficiently. I value how carefully the authors explain the origin of their data and the statistical procedures. The manuscript presents numerous interesting findings and interpretations related to water pollution and sustainable environmental management. The manuscript is referenced more or less adequately, and it bears enough high-quality illustrations. Generally, this is a strong work, although needing some amendments. Please, see my comments below.

• Key words: use short expressions or single words and do not repeat the words from the title.
• Introduction: start with the explanation of the general, international urgency of the topic. Support these considerations with citations of some basic sources.
• 2: please, add a scale bar.
• I encourage you to separate Results from Discussion. The former can present the original findings, and the latter can present their interpretations.
• How have you separated the influence of agriculture from the influence of some other pollution factors?
• Can you add a simple figure showing the pollution changes relatively to the national norms of pollutants (I mean law concentrations of pollutants – I know that there are five classes of norms for water quality in China)?
• Conclusions: add a paragraph considering the limitations of this study and the perspectives for future studies.
• The quality of writing needs improvement. Some sentences need shortening and better phrasing.
• The number of references is enough, but I recommend to diversify the cited literature in order to make this paper sounding more internationally (so, you have to consider some general literature and some papers from the other countries).

Comments on the Quality of English Language

The quality of writing needs improvement. Some sentences need shortening and better phrasing.

Author Response

Thank you for your comments. Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

The authors of the paper “Effects of Agricultural Production Patterns on Surface Water Quality in Central China's Irrigation Districts: A Case Study of the Four Lakes Basin” address a highly relevant topic, namely the influence of agricultural production patterns on surface water quality in irrigation districts in Central China, with a focus on the Four Lakes Basin in the Jianghan Plain. Moreover, this study has the potential to generate a multiplier effect and serve as a reference for other regions worldwide.

However, the similarity index is very high (78%), and we therefore recommend that the authors thoroughly revise the manuscript and reduce the similarity level to an acceptable threshold of approximately 10%.

The concepts, references, and citations are adequately mentioned in the paper. Nevertheless, we suggest that the authors include a distinct literature review section that synthesizes the most relevant bibliographic sources, thereby justifying the sound theoretical foundation of the study.

The research methodology is appropriately presented. For example, the authors employ the Methods for the Monitoring and Analysis of Water and Wastewater (Fourth Edition) [25] as well as methods for estimating water yield and different pollution loads in the FLB. The data are sourced from annual statistical yearbooks published by the Hubei Provincial Bureau of Statistics, covering the period 2010–2022. Still, it would be useful to update the dataset or provide predictive analyses to improve the accuracy and robustness of the findings.

The results are presented both descriptively and graphically, through tables and figures. Among the highlighted findings is that, despite the reduction of nitrogen and phosphorus loads entering Honghu Lake, nutrient concentrations did not decline accordingly, most likely due to climate variability, natural disasters, internal nutrient release, and changes in the carrying capacity of the aquatic environment. Nevertheless, we recommend that the authors explicitly emphasize their innovative scientific contributions, both from a theoretical and applied perspective, in order to underline the multiplier effect of their results.

Regarding the conclusions section, we suggest that the authors clearly outline the study’s limitations, potential future research directions, and the implications of the findings for local government policies.

We congratulate the team on the relevance of the chosen topic and their research effort; however, we strongly recommend a complete revision of the manuscript in light of the high similarity index and the comments provided in this review.

Author Response

Comments 1: 

The authors of the paper “Effects of Agricultural Production Patterns on Surface Water Quality in Central China's Irrigation Districts: A Case Study of the Four Lakes Basin” address a highly relevant topic, namely the influence of agricultural production patterns on surface water quality in irrigation districts in Central China, with a focus on the Four Lakes Basin in the Jianghan Plain. Moreover, this study has the potential to generate a multiplier effect and serve as a reference for other regions worldwide.

However, the similarity index is very high (78%), and we therefore recommend that the authors thoroughly revise the manuscript and reduce the similarity level to an acceptable threshold of approximately 10%.

Response 1:

Thank you for highlighting this point. We fully agree with your comment. The higher similarity index is from our own preprint. The manuscript has been comprehensively revised.

Comments 2:

The concepts, references, and citations are adequately mentioned in the paper. Nevertheless, we suggest that the authors include a distinct literature review section that synthesizes the most relevant bibliographic sources, thereby justifying the sound theoretical foundation of the study.

Response 2:

Thank you for highlighting this point. We fully agree with your comment. Relevant literature resources have been systematically reviewed and summarized in the introduction.

Comments 3:

The research methodology is appropriately presented. For example, the authors employ the Methods for the Monitoring and Analysis of Water and Wastewater (Fourth Edition) [25] as well as methods for estimating water yield and different pollution loads in the FLB. The data are sourced from annual statistical yearbooks published by the Hubei Provincial Bureau of Statistics, covering the period 2010–2022. Still, it would be useful to update the dataset or provide predictive analyses to improve the accuracy and robustness of the findings. 

Response 3:

Thank you for highlighting this point. We fully agree with your comment. The data has been updated from 2022 to 2023, as the latest 2024 Statistical Yearbook released by the Hubei Provincial Bureau of Statistics records data for 2023.

Comments 4:

The results are presented both descriptively and graphically, through tables and figures. Among the highlighted findings is that, despite the reduction of nitrogen and phosphorus loads entering Honghu Lake, nutrient concentrations did not decline accordingly, most likely due to climate variability, natural disasters, internal nutrient release, and changes in the carrying capacity of the aquatic environment. Nevertheless, we recommend that the authors explicitly emphasize their innovative scientific contributions, both from a theoretical and applied perspective, in order to underline the multiplier effect of their results.

Response 4:

Thank you for highlighting this point. We fully agree with your comment. This is an excellent suggestion. The Results and Discussion sections have been written separately, and the innovative scientific contributions of this study have been elaborated.

Comments 5:

Regarding the conclusions section, we suggest that the authors clearly outline the study’s limitations, potential future research directions, and the implications of the findings for local government policies.

We congratulate the team on the relevance of the chosen topic and their research effort; however, we strongly recommend a complete revision of the manuscript in light of the high similarity index and the comments provided in this review.

Response 5:

Thank you for highlighting this point. We fully agree with your comment. In the "Conclusion" chapter, the limitations of this study, potential future research directions, and the implications of the research findings for local government policy-making have been elaborated.

 

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Although the author has made some revisions, I don't think they have seriously revised the work fundamentally. 

Author Response

Thank you for your comments. Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Dear Authors,

Many special thanks for your cooperation!

I wish you all the best and success in your research!

Author Response

Dear reviewer,

Thank you for your review! Your comments are helpful for improving my manuscript's quality.

Round 3

Reviewer 1 Report

Comments and Suggestions for Authors

The manuscript has undergone certain revisions, but there are still some specific minor errors. A thorough check should be conducted throughout the entire manuscript.

1）At the beginning of the manuscript, "Agricultural non-point source" is abbreviated as "(NAPS)", but it is repeatedly expressed as "ANPS" later in the text. It is necessary to confirm which abbreviation to use consistently. Such obvious errors should not occur. Other abbreviations should also be further checked.

2）The scales of the images in the manuscript are inconsistent, which is clearly visible between Figure 1 and Figure 2. This is incorrect.

Author Response

comments:

The manuscript has undergone certain revisions, but there are still some specific minor errors. A thorough check should be conducted throughout the entire manuscript.

1）At the beginning of the manuscript, "Agricultural non-point source" is abbreviated as "(NAPS)", but it is repeatedly expressed as "ANPS" later in the text. It is necessary to confirm which abbreviation to use consistently. Such obvious errors should not occur. Other abbreviations should also be further checked.

2）The scales of the images in the manuscript are inconsistent, which is clearly visible between Figure 1 and Figure 2. This is incorrect.

response:

(1) Thank you for highlighting this point.The abbreviation for "Agricultural non-point source" has been uniformly standardized to "(ANPS)". In addition, in response to your suggestion, we have conducted a comprehensive review of all other abbreviations in the manuscript.

(2) Thank you for highlighting this point. The scales of Figure 1 in the manuscript have been adjusted.