Delineation and Intensity Classification of Freeze–Thaw Erosion in the Western Section of Northern China’s Agro-Pastoral Transition Zone Under Controlling Factors

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Hello, it's my honor to review your manuscript. First of all, I agree with your contribution to this research. The manuscript titled “Spatial Distribution and Intensity Grading of Soil Thaw-Freeze Erosion in the Western Section of the Agro-Pastoral Transition Zone in Northern China” addresses an interesting topic and aligns with the policies of the journal Land. However, several aspects can be improved in order for the manuscript to reach its full potential for publication in Land.

Title. Consider specifying the title more concretely. Since the research is based on factors controlling the erosion process, consider including these factors in the manuscript’s title (e.g., Influence of controlling factors on the spatial distribution...; Geospatial differentiation of erosion according to controlling factors...).

Abstract is well-written and covers the main points that are essential for understanding the issue of Soil Thaw-Freeze Erosion in Khencheli, including the causes, methodology, and results. However, the scientific contribution and novelty of your study are not clearly defined in the abstract.

Keywords. Repetition of keywords from the title should be avoided. In this context, please replace them with alternative terms so that other researchers can more easily find your study.

Introduction. The introduction provides a broad overview of soil thaw-freeze erosion, but the study’s conceptual novelty is not entirely clear. While the introduction is well-grounded in literature, the main research questions could be more sharply stated. What is missing is a clear definition of the research objectives at the end of the introduction, as well as a justification for the choice of this topic. Lines 51-60: It is necessary to add literature references that support your claims. Please provide examples of sediment transport in rivers caused by this process.

Methods. The methodology is systematic, and the methodological framework is solid. Overview of the study area - It is necessary to include the population size. Data Sources are clear and concise. The selected factors are relevant to this process and well defined. However, there is a considerable amount of repetition in the text regarding the process itself and the influencing factors. This is also noticeable at the end of the introduction. Repetition should be avoided. When referring to the results of previous studies, the emphasis is placed on the authors rather than on the research findings. This should be revised. That means sentences should not begin with author names (for example: "Studies by Li Qiang et al. and Wang Xinhao et al. investigated..."). Subsection 2.4.2 should be made more specific. The text is coherent, and it is good that examples from other researchers are included, but from the text alone, it is not clear why the authors selected these specific parameters. It is understandable that this is a set of factors that most influence the given process, but the text should more directly reference the ranges presented in Table 1 (the authors should explain the results from Table 1 in more detail). Also, the results from Table 1 should be incorporated into the main text of the paper. The results related to the Random Forest model and RMSE are methodologically sound. However, the authors need to provide appropriate literature references that clearly demonstrate the methodological validity of the results obtained.

Results.The results are systematic. The authors should ensure that the place names mentioned in the text are also labeled on the maps and figures (readers may not clearly understand where, for example, the Hehuang Valley is located). Figure 4 - In the figure caption, a brief legend should be included. For each color (category) of erosion, the quantitative range of that category should be provided. The color scale is good and appropriately applied.

Discussion. Since land cover and soil moisture are identified as the most significant factors, it is commendable that the authors dedicated specific attention to these in the paper. However, in section 3.1 - Spatial Distribution Characteristics of Thaw-Freeze Erosion Zones, slope angle appears to be emphasized as the main factor influencing erosion vulnerability. This contradiction should be corrected.

Conclusion. The conclusion should be reformulated. It is not necessary to repeat results that have already been discussed. Only the main findings should be briefly highlighted in a few sentences. Additionally, the following should be included:

1. Strengths of the study (e.g., practical applications, how the results can improve resource management or quality of life);
2. Limitations and weaknesses (conceptual, methodological, etc.) and
3. future research directions.

It is recommended that the manuscript be enriched with additional literature sources. Overall, if the authors follow the suggestions and recommendations, the manuscript has the potential to reach its full quality for publication in the Land journal.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

This is an excellent paper, and I believe it is suitable for publication. However, the following issues should be addressed before acceptance:
(1) The authors should elaborate on the significance of this study in the Introduction section.
(2) Some concepts presented in Section 2.3 would be more appropriately placed in the Introduction rather than in the Materials and Methods section.
(3) The colors used in Figures 5 and 6 could be adjusted to improve clarity, as they are currently not very distinguishable.
(4) The Discussion section (Section 4) should be expanded, as the current discussion is rather limited.
(5) The Conclusion should be condensed, as it is currently too lengthy.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Thank you for the opportunity to review your manuscript. Below is a constructive, section-by-section critique with specific suggestions to strengthen the paper.

1. Slope contradiction: You define erosion zones only where slope ≥ 22°, yet Table 1 grades slope intensity up to 20.25° (tier 5). This makes the intensity model inapplicable to the very areas you claim are eroding.
2. Random forest details missing: No description of the response variable, training data, or model validation metrics beyond a single RMSE value.
3. No validation: Neither zone boundaries nor intensity grades are checked against field measurements, sediment records, or independent remote-sensing products.
4. Single-year bias: All analyses rely on 2022 data; inter-annual variability is ignored.
5. Grading bins arbitrary: Table 1 cut-offs lack statistical or literature justification.
6. Title: “Soil Thaw-Freeze Erosion” standardize to “Freeze-Thaw Erosion” throughout (including abstract, figures, tables). “Thaw-freeze” appears only sporadically and confuses readers.
7. Abstract: Add a sentence on validation.
8. Abstract: State the total study area (151,000 km²) for context.
9. Introduction: Add one sentence summarizing why your dual-criterion (cycles + critical slope) is superior and universally applicable.
10. Study Area: “100°50′E–108°40′E”, use consistent notation (e.g., 100°50′–108°40′E).
11. NDVI aggregation: You say “monthly for 2022” but don’t specify how you convert to a single vegetation cover value. State explicitly (e.g., “growing-season maximum NDVI” or “annual mean NDVI”).
12. Critical slope = 22° Justification from Loess Plateau studies is acceptable for that lithology, but the western part includes rocky Qinghai-Tibet margins. Provide a short sensitivity test (e.g., zones at 20° vs. 22° vs. 25°) or cite a study validating 22° in alpine soils.
13. Response variable: What exactly did the RF predict? Field erosion rates? Visual intensity classes? A proxy?
14. Training data: How many field points? Locations? Measurement method (erosion pins, sediment traps, UAV?)?
15. Model performance: RMSE = 0.390 is meaningless without units, R², or comparison to a null model. Provide a learning curve and OOB error.
16. Discussion and conclusion: Compare your weights to prior studies (e.g., Guo et al. 2020 on Qinghai-Tibet).
17. Limitations: 1 km resolution, single year, lack of ground truth.
18. Policy recommendations: Prioritize vegetation restoration in high soil-moisture zones; engineering on steep sunny slopes.
19. Future work: Multi-year analysis, higher-resolution DEM, field validation network.
20. References: Some lack DOI, Add where available.

 

Comments on the Quality of English Language

proof-read please

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

accept