Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The article "An assessment of the N load from animal farms in saline wetland catchments in the Ebro Basin, NE Spain" quantified the nitrogen (N) load from livestock farms across four saline wetland catchments in the Ebro Basin, northeastern Spain, identifying critical cases of N surplus, such as in the Bujaraloz-Sástago basin. The authors employed robust and sophisticated quantification techniques to support their conclusions.

However, I felt the study lacked a more generalized characterization of the basins. While the authors describe these features through tables and text, applying a Principal Component Analysis (PCA) could have provided a clearer, faster, and more efficient way to visualize this baseline data, making it easier to compare the different catchments.

I have noted multiple places where citations should be added, particularly in lines 56 to 70 of the introduction, which cover the justification and importance of the manuscript. Some discussion sections also need this improvement. Regarding the objectives, I suggest specifying them more clearly in the text, and after carefully reading the article, I believe steps 2.3, 2.4, 2.5, and 2.6 could be framed as explicit goals. In these steps, I highlighted the potential use of PCA to better assess patterns. In my opinion, this article is well-written and well-presented; implementing PCA would further enhance its quality. As a biologist working with bat ecology and landscape ecology (biological definition), I am less familiar with studies that don't involve organism-level testing. However, this work appears to be a valuable contribution, providing a good description of spatial and temporal patterns of N discharges and a focused case study on the Farnaca microbasin. While I consider this a well-delimited and well-executed article, its generality is somewhat restricted. Attached, I am sending the PDF with suggestions.

Comments for author File: Comments.pdf

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Abstract

1. The abstract is a little too detailed, which might be confusing for the reader, and it must be more focused.
2. In line 20; explain this abbreviation WEPP ?
3. Some significant results, such as the mention of phosphate (P) and its effects, were not clearly related to the main research purpose.
4. Why are the approaches employed (such as the WEPP model) not sufficiently described in the abstract?
5. In line 30: Some statements are lengthy and complex, reducing message clarity (for example, the sentence "The emphasis on N from animal farms..." (about 45 words), it must be rephrased to be more straightforward.
6. I recommend shortening the abstract to focus on four key elements: a brief introduction, the research purpose, the methodology, the main results, and the most relevant conclusions.

Introduction:

7. The extensive exposition of scientific background may overshadow the fundamental study purpose.
8. Why is there no final paragraph in the introduction that explicitly explains the study topic and primary hypothesis?
9. Some statistics used (such as pig numbers) require direct support from up-to-date references connected to the text rather than merely in the footnote.
10. The introduction discusses agricultural pollution problem in detail; however it fails to identify the research gap that the work seeks to address.
11. Some ideas are repeated between paragraphs (e.g., the discussion of the impact of animal farms on water is repeated in different ways; in lines, 30 ,47, and 68). You should improve this repeat.

Materials and Methods

12. Figure 1; the location of the study area (Map a) is not clear, you must improve it.
13. Why isn't the accuracy of the climate data (CLIGEN generator) described in full, which could have an impact on the work's repeatability?
14. In lines 123-125; put the reference.
15. In table 1; what do you mean by “Depth of water (m)” ?
16. You must change this abbreviation (SAR) because it may overlap with another abbreviation, which is Sodium Adsorption Ratio (SAR). This will be confusing for the reader.
17. In section 2.2. Wetland watershed delimitation: put a figure about LiDAR DTM to illustrate the topographical variation in the basins.
18. Also, you must create a slope map to illustrate the slope gradient of the studied basins.
19. It is better to make the hydrology analysis using ArcGIS to explain how you extracted the watershed basins?
20. In line 180; you should create the land use map of each basin to explain the spatial distribution of crop types.
21. In lines 238-240; “ N output was calculated as the amount ………“ The sentence is too long and lacks clear punctuation to facilitate reading.
22. In line 269; did you obtained 100 years climate data series or 20 years (2003 – 2023)?
23. In section 2.7; Some of the WEPP model settings utilized in the study are not described in depth. Some model details, particularly calibration and validation, should be examined.
24. Some statements are very long and complex, reducing message clarity (for example, the sentence " We estimated the N output per unit……….., in line 191) (about 40 words), it must be rephrased to be more straightforward.
25. Why wasn't soil considered as an influencing factor in the study? It was completely ignored. Ignoring soil as a key factor in the assessment is a methodological weakness and can lead to reduced accuracy in the environmental risk assessment of nitrogen, leading to incomplete or ineffective recommendations on the ground. I want a clear response and a strong explanation for this essential point.
26. Figure 2; you should replace this figure with DEM and slope maps.

Results

27. Why was the background to choosing each scenario (1, 2, and 3) not adequately explained? It is important to clarify why these hypotheses were adopted and what their scientific or field-based basis is.
28. Many sections of the results contain interpretation or discussion, which should be left for the discussion section.
29. In table 5; how did you calculate the cereal area with <15% slope (ha)??
30. Why is there no indication of whether the field data utilized in the models is complete or incomplete?
31. Some tables can be presented in graphs.

Discussion

32. I see an overlap between the results and the discussion, as sometimes the results are restated rather than interpreted or compared to previous studies.
33. There is a notable lack of discussion about the methodology's trengths and weaknesses, you must improve it.
34. Why is there no systematic comparison of past studies at a detailed level, even though many of them are available?
35. Although some practical issues are mentioned, the study does not make specific suggestions for decision-makers or environmental management. This point should be focused on.

Conclusions

36. The conclusion repeats some ideas from the results and does not provide a clear research horizon. You must improve that.
37. Why does the conclusion not provide explicit practical policy or management recommendations drawn from the findings?

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

General comments:

Dear Authors,

I have read your article and highly appreciate the amount of work and methods you have used. The article is a very important consideration of the impact of animal farming on neighboring areas and wetlands, in the form of delivering a load of nitrates and nutrients as a side effect of this branch of agriculture.

• Reconsider the keywords assigned to the abstract: is it necessary to search for your text "soil erosion"? I think it should instead include "WEPP model", maybe with full name (Water Erosion Prediction Project).
• The text requires some formatting corrections: tables are unnecessarily divided into several pages (sometimes their descriptions or footnotes), sometimes a different font has been left.
• Some of the figures (maps) are incorrect in terms of cartography. I have written suggestions on them in the comments to the text section.

Comments to the text:

1. Page 1, line 36 : Add keyword: WEPP model.
2. Page 2, line 76-78: Add source of this information.
3. Page 3, line 101-115: Location map of study areas?
4. Page 4, line 140: Fix the point density description with superscript: / m² or m^-2.
5. Page 5, Figure 1: The part a) has no linear scale. Also show the location of the Ebro drainage basin on the outline of all of Spain.
6. Page 9, Figure 2: The map has no legend (points, perimeters, contour lines).
7. Page 11, Table 8: Two lines are written in a different font.
8. Page 14, line 418: The chapter title should be moved to the next page.
9. Page 15-18, line 419-556: The discussion section is very well and clearly written. I have no particular comments about it.

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

• Line 113; why this reference (astañeda et al. (2015).) has a different style ?
• Figure 2; fix this figure.