The Role of Toposequence and Underground Drainage in Variation of Groundwater and Salinity Levels in Irrigated Areas

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This manuscript provides valuable insight into how toposequence position and subsurface drainage jointly control groundwater dynamics and salinity behavior in semi-arid irrigated systems, offering process-based understanding beyond generalized drainage prescriptions. However, It needs several improvements to make it suitable for possible acceptance.

1. The abstract describes what was done but does not explicitly articulate what gap in existing irrigation–drainage–salinity literature this study addresses.
2. In the introduction, the discussion of the Brazilian semi-arid region and crystalline basement geology is relevant; however, hydrogeological implications could be elaborated.
3. The introduction section should be covered by both global and regional perspectives. Also, the past studies should also have global and regional perspectives while discussing the methodologies and findings of the studies.
4. Studies are cited to support interdependence between irrigation and drainage, but their limitations are not discussed. Add some more literature review by discussing their adopted methodologies and findings, and then highlight how this study advances beyond earlier works. Also, explain why you chose this study?
5. Highlight the broader applicability and significance of your approach.
6. Also, add the study's linkage to any SDG contribution if possible.
7. It is unclear whether previous studies in the São Francisco River Valley have failed to incorporate toposequence analysis. Highlight the research gap and novelty of the study.
8. Also, add the research questions and, hypothesis of the study.
9. Although economic burden of drainage is mentioned, no clear objective addresses economic assessment.
10. Line 116:127:144:  What is Date?
11. The authors can add a study area map, and describing the regions various socioeconomic, geography, topography, etc favtors for better understanding.
12. A flowchart briefly explaining the adopted steps and procedures may be necessary for better readability.
13. In discussion, much of Sections 4.1 and 4.2 restate observations (e.g., presence/absence of water table, EC trends) without sufficiently quantifying differences or statistically validating interpretations.
14. In the discussion section, interpret and discuss your overall findings,,,, and also previous research works can also be discussed here to place the findings in the broader context of existing literature, highlighting the consistencies and discrepancies, and providing a comprehensive perspective on how the current study’s results fit within the broader scientific discourse.
15. The Conclusions section seems too generic. The section mainly restates results without synthesizing them into broader scientific implications.
16. Add the limitations of the study, and future research directions also.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Major revisions (must address)

Clarify the study period and consistency across text and figures, as the study is described as “sixteen months” (March 2017–June 2018), but several results/discussion parts use quarters ending in Feb 2018 (i.e., March 2017–Feb 2018). Please standardize the exact monitoring window everywhere

Also verify and correct any wrong year in figure captions there is at least one inconsistent year in the materials you provided

“Soil water balance” definition is not a soil water balance as written. You compute “balance” essentially as (P + I) – ETo and call it soil water balance. This is closer to a climatic/atmospheric water balance proxy, not a soil water balance missing ETc/actual ET, storage change, drainage/percolation, runoff, capillary rise etc.

Provide a short but complete engineering description for the drained lot

 drain depth, spacing, pipe type diameter, envelope filter, outlet conditions, installation dateage, and whether the collector drains around the perimeter in the middle lot are surface/collector-only (not subsurface). This is important because your concusions depend on with drainage vs without drainage.

Spatial mapping methodology must be stated, currently not reproducible.

Your paper relies heavily on spatial groundwater-surface maps Figures 7–10 etc., but the interpolation workflow is not described adequately.

Add the interpolation method ,  parameters, variogram model, grid resolution, coordinate systemprojection, and how you treated boundaries, missing values and absence of groundwater, any cross-validation or justification that 9 wells/lot supports the chosen mapping approach, the exact definition of the plotted variable

Add at least basic statistics monthly means/medians across wells, variability across wells, and effect sizes e.g., difference in EC between lots with uncertainty Even simple nonparametric comparisons or time-series summaries would improve credibility.

Figures 7–10 and similar multi-panel 3D plots are not readable. The axis ticks, coordinate values, and colorbar labels are too small

Comments on the Quality of English Language

eg. SEPTERMBER typo in Figure 9 panel label

eg. grammar: samples of were … should be samples were …

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Lima et al. designed the experiment to study “The role of toposequence and underground drainage in the variation of groundwater and salinity levels in irrigated areas.” However, the manuscript requires substantial revisions before it can be considered for further evaluation.

The abstract lacks a clear description of the methodology. The authors are requested to clearly state the experimental methods, along with the key findings and major results, in the abstract.

The introduction is very limited and includes too few references. It lacks a comprehensive review of the relevant literature. The authors should discuss similar studies, summarize their key findings, highlight existing gaps or limitations, and clearly explain how the present study addresses those gaps.

The novelty of the study is not clearly stated. The authors should explicitly describe the novel contributions of this work.

The Materials and Methods section requires major revisions to improve clarity and completeness.

In Lines 89–90, the study area location should be reported using proper scientific notation for latitude and longitude. It is also strongly recommended to include a location map of the study area.

Figure 1 should be included in the main manuscript rather than in the supplementary materials. Similarly, Figure 4 should also be incorporated into the main article.

The Discussion section should be strengthened by incorporating more relevant and recent studies to support the findings. The authors should also discuss the challenges encountered during the execution of the study.

The Conclusion section is not convincing and does not adequately summarize the core findings of the study. The authors are encouraged to revise this section to clearly highlight the main outcomes and implications of their work.

Comments on the Quality of English Language

English of the article needs to be improved.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The authors have revised the manuscript as suggested, except one comment: i.e.,  Add more information to the literature review, discussing the methodologies and findings adopted, and highlight how this study advances in relation to previous work. Furthermore, explain why you chose this study.
, After a minor revision, it can be endorsed for acceptance. 

Author Response

"Please see the attachment."

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Thank you for the revisions made to the manuscript. However, a few points still seem to require minor correction to ensure full consistency throughout the text. \

 

In particular, the study period does not yet appear to be fully standardized. In some sections, the study is described as covering twelve months, whereas elsewhere the monitoring period is still given as “March 2017 to June 2018.”

 

Similarly, the caption of Fig. 2 still ends with “June 2018,”

 and the Results section still refers to the absence of precipitation in October 2017 and June 2018.

These details should be carefully harmonized throughout the manuscript, most likely to “March 2017 to February 2018,” if this is the final study period adopted by the Authors.

Regarding Fig. 2, the precipitation values should be formatted according to standard English notation.

Decimal values should use dots rather than commas.

If the axis labels represent whole numbers, it would be preferable to present them without decimal places at all.

A few minor typographical inconsistencies also seem to remain, such as “SEPTERMBER/2017,” “Figure. 12.”, and the formatting of “Fig 7.”

Comments on the Quality of English Language

still SEPTERMBER typo in Figure 9 panel label

 

Author Response

"Please see the attachment."

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Accepted.

Comments on the Quality of English Language

English of the article is fine.

Author Response

"Please see the attachment."

Author Response File: Author Response.pdf