Halophyte-Mediated Metal Immobilization and Divergent Enrichment in Arid Degraded Soils: Mechanisms and Remediation Framework for the Tarim Basin, China
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsPeer Review Report
Manuscript Title: Halophyte-Mediated Metal Immobilization and Divergent Enrichment in Arid Degraded Soils: Mechanisms and Remediation Framework for the Tarim Basin, China
The manuscript presents a research about heavy metal behavior in saline-alkaline soils of the Tarim Basin, combining geostatistical mapping, redundancy analysis, and plant-specific bioaccumulation studies. The integration of spatial modeling with plant physiological data is a strong aspect of the work, and the proposed dual-threshold management framework is relevanx for both science and policy. Some methodological details and presentations require improvement.
Major Comments
The introduction identifies research gaps. They are dispersed across multiple sentences. It would be beneficial to consolidate them into a clear, concise paragraph that explicitly states the novelty of this study relative to existing literature.
The “Materials and Methods” section is detailed, but some critical operational aspects remain unclear like the criteria for selecting the four plant species - should be justified beyond their prevalence in the study area. The rationale for the 0–30 cm soil sampling depth should be explained in the context of deep-rooted species like P. euphratica.
The geostatistical modeling section is strong but could benefit (not necessarilz) bz Including semivariogram plots in the supplementary material.
If authors agree, it would be valuable to include a visual summary (e.g., conceptual diagram) linking environmental variables to heavy metal dynamics.
Just suggestion, not needed to implement: The explanation of P. euphratica’s hyperaccumulation and T. ramosissima’s multi-metal enrichment relies heavily on literature from other species and contexts. Direct measurements of physiological parameters (root exudates, transporter expression) in this study would strengthen these claims.
The framework should address potential socio-economic trade-offs (e.g., switching crops, applying amendments)
Minor Comments
Abstract: Consider avoiding abbreviations like BCF in the abstract unless they are defined immediately. Some sentences are overly long; breaking them up would improve readability.
Figures are correct.
Use consistent units for concentration (mg/kg) throughout the text. Some tables mix µg/kg and mg/kg without immediate clarification.
Some references are dated or region-specific. Consider citing more recent global studies on halophyte-mediated remediation in arid zones.
Recommendation
Major Revision – The study is well-designed. Offers valuable insights. Revisions are necessary to improve methodological clarity, strengthen causal interpretations, and enhance the practical applicability of the proposed framework.
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThe article is devoted to heavy metal immobilization for the Tarim Basin, China. The authors have done a lot of ecological experimental work. However, the mathematical processing of the material raises some questions.
The TS transcript in the abstract should be moved from line 22 to line 16.
The introduction should be expanded. For example, give examples of the use of other plants on soils of similar quality around the world.
Why were these particular plants chosen? At what stage of plant growth were the samples collected? Which part of the plant was tested for heavy metal content? Latin names are partly used in the text of the article, trivial names are also partly used. Please bring the text to uniformity. If the methods proposed in the article are introduced into agriculture, what should be done with the plants that will be grown on contaminated soils?
line 42. It is advisable to replace the adjectives “domestic” with “Chinese”.
line 70. It is advisable to replace the word “vs.” in the phrase “economic crops vs. halophytes”.
table 1. The year of manufacture and the country of manufacture for each device should be written.
For each program used, you need to write the year of release of the program and the manufacturer.
Table 2. Why are the R2 values for all elements except As so low?
Table 3. How are the “Mean” and “Standard Deviation” parameters calculated?
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsComments for sustainability-3834573
In this study, Liu et al. studied heavy metal dynamics, including Hg, As, Cd, Cu, Pb, and Zn, in arid saline soils of the Tarim Basin by analyzing various soil and plant samples. Their findings showed that high salinity and alkalinity immobilized As, Cd, Cu, and Zn, reducing their mobility by up to 68%. Plant species showed different enrichment patterns, such as P. euphratica hyperaccumulated Cd and Zn, T. ramosissima accumulated As and Pb, cotton posed Hg transfer risks, and jujube neared Cd safety limits. Additionally, soil pH and salinity suppressed metal bioavailability, while phosphorus and organic carbon enhanced it.
The study is well-conceived and presents some innovative features, particularly the proposed dual-threshold management framework that combines natural immobilization through high salinity/alkalinity with phosphorus control to mitigate crop Cd risks. Highlighting P. euphratica as a phytoremediation candidate also adds practical value. Overall, the work has merit and can be considered for publication after addressing the following concerns.
- The introduction is too broad initially; it should focus earlier on salinity and HM interactions. The research gaps are stated, but not clearly linked to how this study addresses each of them. Kindly revise it, addressing these gaps.
- Since the study reports that euphratica hyperaccumulated Cd and Zn, and T. ramosissima accumulated As and Pb, it would be essential to clarify whether these species are naturally known hyperaccumulators of these metals. If not, were any associated physiological or ultrastructural disorders observed as a result of such heavy metal accumulation?
- Different analytical techniques were used for measuring different metals (e.g., HG-AFS for As, ICP-MS for Cr, ICP-OES for Zn, etc.). What is the rationale for selecting different methods for different elements?
- The authors may consider expanding the concluding remarks by outlining potential future research directions. For instance, could long-term field trials be designed to validate the proposed dual-threshold management framework under varying salinity-alkalinity conditions? Additionally, are there opportunities to explore genetic or physiological adaptations in euphratica and T. ramosissima that underpin their selective metal accumulation, which could further strengthen their role in phytoremediation strategies for degraded saline lands?
Overall, English is good, but there is room for improvement
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 4 Report
Comments and Suggestions for AuthorsThis manuscript focuses on the Tarim Basin and investigates the migration characteristics of heavy metals in arid saline-alkaline soils as well as the enrichment mechanisms of different plant species. Based on 323 soil samples and 55 plant samples, the study applies geostatistics, redundancy analysis (RDA), and bioconcentration factors (BCF) to systematically analyze the roles of salinity, pH, soil organic matter, and nutrients in driving heavy metal mobility and bioavailability. A dual-threshold management framework of “salinity-alkalinity immobilization and phosphorus regulation” is proposed. The topic is regionally relevant, supported by a relatively large dataset, and the results provide potential guidance for pollution risk prevention and vegetation allocation in saline-alkaline farmlands of arid regions. However, the manuscript still presents some issues that need improvement, including limited novelty of the proposed framework, insufficient representativeness of plant sampling, over-reliance on statistical inference without deeper process-based validation, and a lack of practical evidence to support the applicability of the management strategy. Furthermore, parts of the discussion rely heavily on speculation with insufficient data support, and the overall structure could be streamlined to highlight key findings more clearly.
1.It is recommended that in both the abstract and the main text, all abbreviations be written out in full at their first occurrence, followed by the abbreviation in parentheses, to ensure clarity and smooth comprehension for readers.
2.The abstract successfully summarizes the main findings and introduces the concept of a “dual-threshold management framework,” which is commendable. However, its practical applicability has not been fully demonstrated. It is recommended that the abstract briefly elaborate on how this framework could be applied in the management of degraded saline farmlands or in vegetation allocation, so that the study goes beyond theoretical discussion and better reflects its guiding significance for practical work.
3.While the introduction mentions that about 25% of global farmland soils are contaminated with heavy metals and briefly notes reduced bioavailability in saline environments, it lacks a deeper discussion of the distinctive hydrosaline conditions in arid regions and their unique effects on metal migration. More region-specific background information would strengthen the rationale.
4.The current literature review is somewhat fragmented, focusing mainly on general methods (such as geostatistics and pollution indices). A more systematic synthesis of previous research on heavy metal migration, plant enrichment, and coupled mechanisms under arid saline conditions would better highlight the knowledge gap.
5.Although three research gaps are listed, the statements remain somewhat broad. For example, noting that “most studies focus on individual metals” or “comparative studies of plant types are lacking” would be more convincing if linked to specific examples or data from existing studies.
6.The final paragraph clearly presents the study’s scope and methods in introduction, but the description is relatively lengthy. Streamlining the objectives while emphasizing the core research questions and expected contributions would help readers quickly grasp the study’s value.
7.Although a “grid + patch” layout was employed, the representativeness of sampling for different vegetation types is not sufficiently described. It is recommended to clarify the sample distribution across vegetation types and its statistical adequacy to strengthen the reliability of the conclusions.
8.While the analytical methods and detection limits are listed in the tables, details regarding measurement precision and reproducibility are insufficient. Additional information on error ranges and quality assurance procedures should be provided.
9.The section mentions the use of various statistical and geostatistical tools, but the rationale for model selection is not clearly explained. For example, the criteria for choosing semivariogram models and the significance testing procedures in RDA should be clarified to improve methodological transparency.
10.Although the study follows the “Specification for Land Quality Geochemical Assessment,” comparisons with national or international soil environmental standards are missing. Including these references would highlight the environmental relevance of the results.
11.In the captions and notes of the figures and tables, all abbreviations should be fully explained, with the full term provided at their first occurrence followed by the abbreviation in parentheses, to ensure readers can clearly understand the content.
12.Some result descriptions are lengthy and overly descriptive. It is recommended to streamline the content and emphasize findings directly relevant to the study objectives.
13.While values such as BCF and RDA outcomes are presented, the statistical significance of some observed differences or trends is not sufficiently explained. Including significance levels or confidence intervals would strengthen the credibility of the results.
14.The figures and tables are informative, but some legends and captions remain too brief, with certain abbreviations left unexplained. Providing complete explanations in the figure captions would facilitate reader understanding.
15.The Results section occasionally introduces mechanistic interpretations. These explanations should preferably be reserved for the Discussion, while the Results section should focus on presenting the data objectively.
16.The discussion of immobilization mechanisms focuses mainly on macro-level processes such as precipitation and ion exchange, but lacks supporting evidence at the micro or molecular level. Referring to studies involving micro-scale processes or isotopic tracing would strengthen the scientific rigor of the mechanistic interpretation.
17.Although some references are cited, the comparison with existing research remains insufficient, especially regarding results from other regions or different plant types. A more thorough comparison would better highlight the novelty of this work.
18.The management framework is a valuable contribution, but its practical implementation in agricultural or ecological restoration settings is not clearly addressed. Including concrete examples or potential field practices would enhance its applicability.
19.The discussion pays little attention to limitations, such as the single sampling period, limited number of plant samples, or the absence of direct measurements from edible plant parts. It is recommended to add a section at the end of the discussion acknowledging these limitations and suggesting directions for future research.
20.The Conclusions section provides a coherent summary of the study’s key findings, including heavy metal immobilization under saline-alkaline conditions, the enrichment differences among plant species, and the proposal of the “dual-threshold management framework.” Overall, it aligns well with the research objectives and carries practical significance. However, improvements are still needed. The conclusions should more clearly emphasize the novelty of the study to highlight its unique contributions. The content should also be streamlined to avoid excessive length and repetition of results, thereby making the conclusions more concise and impactful. In addition, it is recommended to briefly address the potential applications of the framework in agricultural management and ecological restoration, and to outline directions for future research to enhance the forward-looking and practical relevance of the study.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsReviewer’s Comment
I thank the authors for their careful and thorough revisions. They have successfully addressed all of the reviewers’ suggestions, and the manuscript is now substantially improved in clarity, methodological justification, and overall scientific contribution.
All of my previous concerns have been adequately resolved, and I have no further comments. In my view, the manuscript in its current form meets the journal’s standards for publication.
Recommendation: Accept.
Author Response
Manuscript ID: sustainability-3834573
Title: Halophyte-Mediated Metal Immobilization and Divergent Enrichment in Arid Degraded Soils: Mechanisms and Remediation Framework for the Tarim Basin, China
Authors: Jingyu Liu, Lang Wang, Shuai Guo and Hongli Hu
Dear Reviewer,
We are delighted to receive your positive feedback and final decision on our manuscript.
Thank you very much for your time and effort in reviewing our work. We are deeply grateful for your insightful comments and suggestions throughout the review process, which have been invaluable in helping us to improve the quality and clarity of our manuscript.
We are also very pleased to hear that you found our revisions to be thorough and that all of your previous concerns have been adequately addressed.
Once again, we sincerely appreciate your contribution to our paper.
Best regards,
Jingyu Liu
Reviewer 2 Report
Comments and Suggestions for AuthorsI thank the authors and the editors of the journal for the work done.
The article can be published in this form.
Author Response
Manuscript ID: sustainability-3834573
Title: Halophyte-Mediated Metal Immobilization and Divergent Enrichment in Arid Degraded Soils: Mechanisms and Remediation Framework for the Tarim Basin, China
Authors: Jingyu Liu, Lang Wang, Shuai Guo and Hongli Hu
Dear Reviewer,
We are delighted to receive your positive feedback and final decision on our manuscript.
Thank you very much for your time and effort in reviewing our work. We are deeply grateful for your insightful comments and suggestions throughout the review process, which have been invaluable in helping us to improve the quality and clarity of our manuscript.
We are also very pleased to hear that you found our revisions to be thorough and that all of your previous concerns have been adequately addressed.
Once again, we sincerely appreciate your contribution to our paper.
Best regards,
Jingyu Liu
Reviewer 3 Report
Comments and Suggestions for AuthorsIn the revised version, the author has adequately addressed my previous concerns, and the paper may be considered for publication after minor revisions.
Lines 51–54: Please revise this sentence to keep the narrative more general, for example by using phrases such as ‘literature has reported…’ or ‘researchers have investigated.’
Line 59, 470, etc.: Ensure that all scientific names are italicized.
Comment 3: The points are addressed well in the response letter; the corresponding changes in the manuscript (lines 172–177) are insufficient. It is recommended that the suggested text also be incorporated into the manuscript.
Author Response
Manuscript ID: sustainability-3834573
Title: Halophyte-Mediated Metal Immobilization and Divergent Enrichment in Arid Degraded Soils: Mechanisms and Remediation Framework for the Tarim Basin, China
Authors: Jingyu Liu, Lang Wang, Shuai Guo and Hongli Hu
Dear Reviewer,
We wish to express our sincerest gratitude for your time and for providing the positive feedback and final minor recommendations on our revised manuscript.
We are delighted that you found our previous revisions to have adequately addressed your concerns. We have carefully incorporated all of your additional suggestions, including the generalization of the narrative tone, the italicization of scientific names throughout the text, and the enhanced clarification of our methodological rationale in Section 2.2. We believe these changes have further strengthened the manuscript.
Thank you once again for your invaluable insights and for guiding us through the review process. Your efforts have significantly improved the quality of our work.
Please see the attached document for a point-by-point response to your specific comments.
Best regards,
Jingyu Liu
In the revised version, the author has adequately addressed my previous concerns, and the paper may be considered for publication after minor revisions.
Comment 1: Lines 51–54: Please revise this sentence to keep the narrative more general, for example by using phrases such as ‘literature has reported…’ or ‘researchers have investigated.’
Response 1：Thank you for your constructive suggestion. We have revised the sentence in Lines 51–54 to present the statement in a more general and academically conventional form, using the phrase "Extensive literature has reported..." as recommended. The modified sentence better aligns with the formal tone of the manuscript. (Page 2, Lines 53-56)
Comment 2: Line 59, 470, etc.: Ensure that all scientific names are italicized.
Response 2：Thank you for pointing this out. We have carefully reviewed the manuscript and ensured that all scientific names are now properly italicized throughout the text, including those mentioned in Line 59 and Line 470.
Comment 3: The points are addressed well in the response letter; the corresponding changes in the manuscript (lines 172–177) are insufficient. It is recommended that the suggested text also be incorporated into the manuscript.
Response 3：We sincerely thank the reviewer for this comment and for pointing out the insufficiency in our previous revision. We sincerely apologize for this oversight. We have now fully incorporated the suggested text (the rationale for selecting different analytical methods for different elements, as provided in our response letter) into Section 2.2 of the manuscript. The added content details our adherence to national standards and the performance-based reasons for method selection, ensuring the manuscript now fully addresses this point. We greatly appreciate the reviewer's careful review, which has helped improve the clarity of our methodology. (Page 5, Lines 172-186)
Reviewer 4 Report
Comments and Suggestions for AuthorsIt now meets the journal's standards. I recommend acceptance for publication.
Author Response
Manuscript ID: sustainability-3834573
Title: Halophyte-Mediated Metal Immobilization and Divergent Enrichment in Arid Degraded Soils: Mechanisms and Remediation Framework for the Tarim Basin, China
Authors: Jingyu Liu, Lang Wang, Shuai Guo and Hongli Hu
Dear Reviewer,
We are delighted to receive your positive feedback and final decision on our manuscript.
Thank you very much for your time and effort in reviewing our work. We are deeply grateful for your insightful comments and suggestions throughout the review process, which have been invaluable in helping us to improve the quality and clarity of our manuscript.
We are also very pleased to hear that you found our revisions to be thorough and that all of your previous concerns have been adequately addressed.
Once again, we sincerely appreciate your contribution to our paper.
Best regards,
Jingyu Liu
