A Rapid Assessment Technique for Identifying Future Water Use and Pesticide Risks Due to Changing Cropping Patterns
Round 1
Reviewer 1 Report
Comments and Suggestions for Authors
The manuscript “Identifying Future Water Quantity and Water Quality Challenges from Agriculture” addresses emerging issue in sustainability governance, climate change policy and adaptation planning in general . The following suggestions could improve the manuscript further
General comments
· The title needs to be revised to reflect the main content of the study ( specifically risk aspects).
· Statement of the problem need to be more explicit , specifically around the issues of shifting vulnerabilities ( externalities) and sustainability governance in adaptation planning. This should also inform background information/ introduction section.
Methodology
Addressing the following could address some short comings in the study.
1. A brief description on the climatic trends of the study area in terms of rainfall/ water trends
2. What are the observed and expected climate scenarios ?
3. What are the various crop water requirement scenarios against changing rainfall/ irrigation regimes and concomitant risks profiles i.e., through Monte Carlo sampling ?
4. Related to 3 above is sensitivity analysis ( historical crop water requirements , thresholds) on crop water demand against observed and expected climatic change.
5. Having said so, (1-4) , use of suitable visualization tools such as box plot will make the results more presentable.
6. Including assumptions considered could make the study more focused.
7. The discussions and conclusion need to reviewed in line with the above suggestions and revised statement of the problem as suggested under general comments.The manuscript “Identifying Future Water Quantity and Water Quality Challenges from Agriculture” addresses emerging issue in sustainability governance, climate change policy and adaptation planning in general . The following suggestions could improve the manuscript further
General comments
· The title needs to be revised to reflect the main content of the study ( specifically risk aspects).
· Statement of the problem need to be more explicit , specifically around the issues of shifting vulnerabilities ( externalities) and sustainability governance in adaptation planning. This should also inform background information/ introduction section.
Methodology
Addressing the following could address some short comings in the study.
1. A brief description on the climatic trends of the study area in terms of rainfall/ water trends
2. What are the observed and expected climate scenarios ?
3. What are the various crop water requirement scenarios against changing rainfall/ irrigation regimes and concomitant risks profiles i.e., through Monte Carlo sampling ?
4. Related to 3 above is sensitivity analysis (historical crop water requirements, thresholds) on crop water demand against observed and expected climatic change.
5. Having said so, (1-4), use of suitable visualization tools such as box plot will make the results more presentable.
6. Including assumptions considered could make the study more focused.
7. The discussions and conclusion need to review in line with the above suggestions and revised statement of the problem as suggested under general comments.
Comments for author File: 
Comments.pdf
Only minor edit of English language required.
Author Response
We appreciate your comments related to climate scenarios and trends. The paper, however, is not focused on climate; rather, it is focused how changes in cropping patterns would affect the environmental impacts of agricultural production. More specifically, we present a low-cost method for assessing how agricultural water withdrawals and pesticide risk profiles change as crops change. The idea here is to illustrate how a resource-constrained agricultural extension service or environmental management agency could quickly identify potential changes in environmental impacts in order to prioritize areas for further assessment and/or investments in risk mitigation programs.
Author Response File: Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThis paper explores the consequences of shifting from row crop to vegetable production in terms of water withdrawals, water quality, and pesticide risks. The authors develop a methodology for comparing the environmental risks of different crops and provide insights into how cropping patterns can impact water resources and pesticide use. The paper emphasizes the importance of understanding the implications of shifting cropping patterns for long-term water resource sustainability. However, there are still some limitations and areas that need improvement in the paper. This reviewer believes that with further improvements, the paper could be of great value to its readers.
Some major issues:
1) The paper could benefit from a more comprehensive review of relevant literature to provide a stronger theoretical foundation for the study.
2) The paper should provide more context and background information on the current state of agriculture in the southeastern United States and the specific challenges and opportunities in the region. This would help readers better understand the significance of the findings.
3) Could the authors provide more details on the specific data sources and methods used for the analysis? How representative are the data and results for the southeastern United States? More information on these aspects would be helpful for readers to understand and reproduce the study.
4) The paper does not provide a thorough evaluation and comparison of the proposed method with existing approaches in the field, particularly lacking a clear discussion of the limitations and uncertainties of the methodology used. This limits the assessment of the novelty and effectiveness of the methodology.
5) It is recommended that the authors strengthen the comparison of their results with existing literature on the consequences of shifting cropping patterns.
6) Have the authors considered the economic implications of shifting cropping patterns on farmers and the agricultural industry? If not, do the authors have any plans to address this aspect in future research?
7) What are the potential implications of the findings for agricultural policy and decision-making in the southeastern United States? How can the results be used to inform sustainable agricultural practices?
8) The paper could benefit from a clearer and more concise presentation of the results, with better labeling and organization of the figures. This would improve the readability and understanding of the findings.
9) Judging solely on the content of the paper, the authors do not provide a detailed discussion on future water quantity and water quality challenges from Agriculture. The content seems disconnected from the title.
Author Response
Response to Reviewer 2
The paper should provide more context and background information on the current state of agriculture in the southeastern United States and the specific challenges and opportunities in the region. This would help readers better understand the significance of the findings.
The specific findings of the case study in the US are not the primary objective of the study. The primary objective is to demonstrate that a rapid assessment of the pesticide risk and water use impacts of changing cropping patterns is possible.
Could the authors provide more details on the specific data sources and methods used for the analysis? How representative are the data and results for the southeastern United States? More information on these aspects would be helpful for readers to understand and reproduce the study.
We have expanded the methodology section to include details of the risk thresholds.
The paper does not provide a thorough evaluation and comparison of the proposed method with existing approaches in the field, particularly lacking a clear discussion of the limitations and uncertainties of the methodology used. This limits the assessment of the novelty and effectiveness of the methodology.
We are not proposing our approach is superior to other techniques used to assess environmental impacts from agricultural production. We also readily acknowledge the subjectivity inherent to setting threshold levels for relative pesticide risks. The purpose of the study is to demonstrate that a rapid assessment using publicly available information and free, downloadable modeling software can be done to see how the environmental risk profile changes with crop choice.
Have the authors considered the economic implications of shifting cropping patterns on farmers and the agricultural industry? If not, do the authors have any plans to address this aspect in future research?
We do plan to address the economic drivers of crop selection in future research. Historically, row crops have been more profitable than fruit and vegetable crops in the study area. This is, in part, due to the relatively cheap production costs for fruits and vegetables in the western United States. Climate models project significant changes to precipitation patterns in the western US that will certainly impact the quantity, quality, and costs of fruit and vegetable production there in the future. With steady or increased demand and lower supply, fruit and vegetable prices are likely to rise making them relatively more attractive to growers in the southeast. The crop selection decision of farmers will, of course, also depend on how the future profitability of row crop production is affected as well.
What are the potential implications of the findings for agricultural policy and decision-making in the southeastern United States? How can the results be used to inform sustainable agricultural practices?
The results are intended to be used by agricultural extension and environmental management agencies to strategize and prioritize scarce resources in the development of risk mitigation programs. For example, the pesticides used in row crop production in the study area pose a much greater risk to groundwater than surface water resources. If growers in the study area were to shift to fruit and vegetable production, the pesticides they would employ would pose a greater risk to surface water. Understanding that change in the risk profile would facilitate the development of extension programs focused on limiting pesticide runoff as opposed to pesticide leaching.
The paper could benefit from a clearer and more concise presentation of the results, with better labeling and organization of the figures. This would improve the readability and understanding of the findings.
We have changed the labeling of the figures.
Judging solely on the content of the paper, the authors do not provide a detailed discussion on future water quantity and water quality challenges from Agriculture. The content seems disconnected from the title.
Thank you for this comment. We have changed the title of the paper and feel it now reflects the content more precisely.
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsThe article titled “Identifying Future Water Quantity and Water Quality Challenges from Agriculture” represents the consequences on water withdrawals and water quality of shifting from row crop to vegetable production in the southeastern United States (US). Although the study objective is mentioned, the article is not ready for publication. As such, the authors should show what are the new concepts, and innovations of this work.
1. The figures caption should be located below the image.
2. How were the numerical indices calculated?
3. The number of references 18 is insufficient
4. Please provide the comparison of your water quantity with recently published article, because I think that the study outputs are very general and shallow on the water quantity consequences
5. Discussion on Figure 7 (Pesticide Loads by Aquatic Species Risk and Crop) is not satisfactory.
6. Please provide more explanation regarding pesticide risk and fertilizer loads by cropping system.
7. The discussion lacks scientific knowledge about the transfer of pesticide loads through aquatic species
8. The Conclusion about “in the lower Flint River basin of Georgia” should be expanded to have broad and worldwide applications.
Comments on the Quality of English LanguageModerate editing of English language required
Author Response
Response to Reviewer 3
The figures caption should be located below the image.
The captions for all figures have been moved to below the image.
How were the numerical indices calculated?
We appreciate this comment, but are not sure which numerical indices you are referring to. The main point of the article is to demonstrate that relatively low-cost techniques can be used to identify how the profile of environmental stressors will shift as crop selection adjusts due to climate change. The idea is that numerical indices that incorporate site-specific information are valuable but data-intensive and expensive. By breaking pesticide risks into three distinct levels (high, medium, and low) across discrete environmental categories using publicly available information we can get a very good depiction of how the environmental stress profile changes with crop selection. This approach can serve as a relatively inexpensive “early warning signal” that can help local agricultural and environmental agencies direct resources as cropping patterns change.
The number of references 18 is insufficient
We have added many new references. Thank you for encouraging us to expand the citations.
Please provide the comparison of your water quantity with recently published article, because I think that the study outputs are very general and shallow on the water quantity consequences
The water quantity analysis was done using DSSAT. We have provided many new citations related to the use of DSSAT for modelling irrigation water withdrawals. The DSSAT modelling was done to support the Georgia State Water Plan. We have also included citations for expected irrigation water withdrawals for corn, cotton, peanut, and soybean production in the Lower Flint River basin (LFRB), and for brassica crops in southwest Georgia where the LFRB is located.
Please provide more explanation regarding pesticide risk and fertilizer loads by cropping system.
The expected fertilizer and pesticide loads by cropping system come from the UGA Extension Enterprise Budgets. The pesticide risk to each environmental category is based on the toxicity and persistence of its active ingredient, as explained in section…
The discussion lacks scientific knowledge about the transfer of pesticide loads through aquatic species
The actual transfer of pesticide loads through aquatic species is highly dependent on environmental factors within the aquatic environment. The purpose of this paper is to provide a method for a preliminary assessment of how risks to aquatic species could change with crop selection. This preliminary assessment is meant to identify areas where extension services and environmental management programs may need to be enhanced as agricultural production changes in a given location.
Author Response File: Author Response.pdf
Reviewer 4 Report
Comments and Suggestions for AuthorsThe manuscript addresses a topic of significant interest with potential implications for agricultural practices. However, the methodology must have the scientific rigor necessary to understand the study's implications comprehensively. Specific areas of concern include:
- Model Calibration and Validation:
- The manuscript needs to provide detailed information on the calibration and validation of the models used, particularly the Decision Support System for Agrotechnology Transfer (DSSAT). Calibration and validation are crucial to establishing the reliability of model predictions across different crops and regional conditions. A detailed explanation of these processes would significantly enhance the manuscript's scientific rigor.
Narrow Focus on Median Water Withdrawals:
- While the methodology section describes using DSSAT and cumulative distribution functions to estimate irrigation requirements, the results section primarily presents median water withdrawals for row crops versus vegetables. This narrow focus overlooks the broader variability and the diverse factors influencing irrigation needs.
The manuscript extensively references another publication for its methodological framework, which may hinder readers' ability to fully grasp the applied methods and their relevance to the current study. Although leveraging established methodologies is not inherently problematic, a more comprehensive integration and explanation within the manuscript would allow for a self-contained and transparent presentation of the research approach. On reading the publication [7], it looks like more data may be involved in calculating various parameters, which are essentially unknown to the readers in terms of how they were obtained/calculated. More explicit exposition of all data sources and their roles in the analysis would provide a more complete picture of the methodological approach.
To enhance the manuscript's contribution to the field, addressing these concerns with detailed methodological descriptions, expanded analyses, and a more transparent integration of external methodologies is recommended.
Comments on the Quality of English LanguageNo issues here
Author Response
Response to Reviewer 4
- The manuscript needs to provide detailed information on the calibration and validation of the models used, particularly the Decision Support System for Agrotechnology Transfer (DSSAT). Calibration and validation are crucial to establishing the reliability of model predictions across different crops and regional conditions. A detailed explanation of these processes would significantly enhance the manuscript's scientific rigor.
- DSSAT is a widely used crop simulation model. Information related to model calibration and validation is extensive and would take far too much space to address in a comprehensive manner. Multiple references have been added to illustrate the scope of the use of DSSAT.
Narrow Focus on Median Water Withdrawals:
- While the methodology section describes using DSSAT and cumulative distribution functions to estimate irrigation requirements, the results section primarily presents median water withdrawals for row crops versus vegetables. This narrow focus overlooks the broader variability and the diverse factors influencing irrigation needs.
- Thank you for this comment. The results section shows the entire estimated cumulative distribution function for irrigation water use by crop, not just the median withdrawals. The discussion, however, was focused primarily on the median value. We have changed the wording of that section to address the variability of withdrawals as well as the median values.
The manuscript extensively references another publication for its methodological framework, which may hinder readers' ability to fully grasp the applied methods and their relevance to the current study. Although leveraging established methodologies is not inherently problematic, a more comprehensive integration and explanation within the manuscript would allow for a self-contained and transparent presentation of the research approach. On reading the publication [7], it looks like more data may be involved in calculating various parameters, which are essentially unknown to the readers in terms of how they were obtained/calculated. More explicit exposition of all data sources and their roles in the analysis would provide a more complete picture of the methodological approach.
We have added the details of how the pesticide relative risk thresholds were established.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
Comments and Suggestions for AuthorsAfter the authors' revision, the quality of the paper has been further improved. However, there are still some minor issues.
(1) I still insist that the authors should provide more background information on the current agricultural development in the southeastern United States and the specific challenges and opportunities in the region. This will help readers better understand why the authors chose this study area for related research instead of other regions.
(2) The quality of all figures could be further improved. It is recommended that the authors enhance the visual appeal of all figures, with particular attention to refining the axes.
Author Response
(1) I still insist that the authors should provide more background information on the current agricultural development in the southeastern United States and the specific challenges and opportunities in the region. This will help readers better understand why the authors chose this study area for related research instead of other regions.
Thank you for this comment. We have added a paragraph and two new figures to the introduction to illustrate historical crop production in the study area and projected future water stress in the study area compared to the west coast. We have also added an additional reference citing the vast amount of land in the southeast suitable for vegetable production. We hope this better explains the relevance of the study area.
(2) The quality of all figures could be further improved. It is recommended that the authors enhance the visual appeal of all figures, with particular attention to refining the axes.
We were unable to design an improvement to the figures. We are not sure exactly what is meant by “refining the axes” but are more than willing to take any recommendations for refinement.
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsThe authors responses are satisfactory
Comments on the Quality of English LanguageMinor editing of English language required
Author Response
Thank you for your valuable feedback.
Reviewer 4 Report
Comments and Suggestions for AuthorsAccept
Author Response
Thank you for your valuable feedback.
