Application of GIS Technology in Soil Quality Management and Agricultural Development Orientation in Vietnam

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The manuscript presents a GIS-based assessment of soil quality and land suitability applied to a district in the Red River Delta, Vietnam. The study is technically sound and makes use of original soil sampling data combined with GIS overlay techniques. However, the manuscript remains predominantly descriptive and application-oriented, with limited methodological innovation or analytical depth.

 

Abstract

The abstract should be restructured to explicitly include the method used (Multi-Evaluation Criteria – MEC) to assess and classify soil quality and land suitability. In addition, the main quantitative results should be clearly presented in the abstract. These improvements would enhance the structure of the abstract and increase its attractiveness to readers.

 

Introduction

The introduction is well written; however, the scientific gap is not clearly articulated. For example:

Are there no existing studies applying GIS to the specific objective addressed here?

What are the limitations of current GIS-based approaches?

Is there a lack of integration between GIS-based land suitability assessment and territorial planning under accelerated urbanization?

I recommend explicitly stating the scientific gap and supporting it with citations from previous studies that highlight these limitations.

In addition, citations should be adjusted to comply with the journal’s numerical citation format.

 

Study Area

Figure 1 – Please add a coordinate grid with latitude and longitude values to improve spatial reference.

 

Research Methods

The manuscript does not provide line numbers, which made it difficult to indicate precise locations for comments and recommendations.

I recommend presenting the collected data (reports, climatic data, agricultural data, maps) in bullet points or in a table. In its current form, the description is generic and difficult to follow.

 

Soil Quality Sampling Method

Please clarify the depth at which soil samples were collected and include this information explicitly in the manuscript.

It would also be useful to add a map showing the spatial distribution of soil sampling points.

 

Method for Developing the Crop Development Orientation Map

The authors applied the MEC method; however:

it is not clear whether criteria were equally weighted or assigned different weights;

there is no technical justification for the selection of criteria;

the aggregation function used in ArcGIS is not described.

I recommend clearly stating whether uniform or differentiated weighting was applied, justifying the criteria and their hierarchy, and formally presenting the MEC logic or equation.

Please also clarify the total area analyzed and indicate which land-use classes, if any, were excluded from the analysis (urban).

 

Results

The first subsection of the Results (“4.1 Current status of agricultural land use in An Duong District”) reads more like contextual justification than a results section, as it mainly reports land-use planning data.

The first paragraph of Section 4.2 can be removed, as it is redundant:

“The results of the agricultural soil quality analysis in An Duong District are summarized and presented in Table 5.”

Given the soil analysis dataset, could the authors interpolate these data to generate a spatial soil quality map and incorporate it into the land quality or suitability analysis?

In Section 4.3, the manuscript presents the database and the characterization of the study area based on these data. This content would fit better in the Materials and Methods section, as it primarily describes data inputs rather than results. I recommend restructuring this section to clearly separate methods from results.

In Table 6, the “Land Quality Unit” column is presented, but the reader cannot identify where these units are spatially located. I recommend adding a map in the Methods section showing the spatial distribution of the land mapping units and clarifying that the analysis is based on these units.

Figure 3 is not legible. The text, legend, and colors cannot be properly interpreted. The overall quality of the figure and its visual elements needs substantial improvement.

What is the practical meaning of the S2 and S3 classes? Are “marginally suitable” areas economically viable? What are the potential risks of suitability overestimation, given that 100% of the area is suitable for vegetables and more than 99% is suitable for rice? These aspects require a more critical discussion.

I recommend restructuring the Discussion to include explicit comparisons with GIS–MCE studies conducted in other countries, to discuss methodological limitations, and to address implications for replicability in other regions.

The quality of Figure 4 should also be improved, as the current resolution does not allow proper analysis.

The methodological workflow follows classical GIS overlay approaches that have been widely used for decades. The novelty of the study lies mainly in its local application rather than in methodological advancement. I recommend explicitly positioning the manuscript as an applied case study or strengthening the methodological contribution through additional analyses.

Finally, the suitability maps are not validated with independent data (e.g., current land use, observed crop productivity, or yield statistics). I recommend validating the results using such data or, at minimum, explicitly discussing this limitation.

Author Response

Dear Review,

Thank you for your recommendation about my draft article. Please see my edits in the attached file.

Best regards,

Son

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Thank you for conducting this study. There are some comments provided below that must be considered:

• Page 2: “constructing works serving agricultural production on rice land...” please remove “…” and use “etc”.
• Page 4: “average annual rainfall is approximately 1,263 mm, concentrated mainly in the summer months from May to August, and the average relative humidity ranges from about 88% to 92%.” Please report the annual average of temperature.
• Page 5: “a total of 96 topsoil samples were collected from agricultural land across the district”. What is the total area for this sampling. Is it only for agricultural lands or it is for the total area. How was your grid design for soil sampling?
• Page 6: “After developing the soil quality map, land suitability assessment was conducted for six crop types in the study area, including rice, maize, vegetables, potato, flowers, and fruit trees.” How did you consider all trees the same. Every tree has some specific land suitability that might be different from the others. It is the same for the flowers.
• Figure 2 is not clear and presentable well. It crosses the lines. Please correct it.
• Page 8: “4.1. Current status of agricultural land use in An Duong District” why is it described. Is it derived from your current study. It seems no. So, I recommend summarizing it and moving to the Study Area section or Introduction section.
• Table 5: I believe when the soil quality maps for every single material are created, it is unnecessary to present them in a table especially for the Sand, Silt and Clay. The text after table 5, which is a description of the table, is also unnecessary. This description should be for the maps and their statistical explanation associated with the spatial distribution.
• This study lacks geospatial analysis. For creating spatial distribution maps, it is necessary to describe the geospatial analysis including variogram and interpolations methods and rate of over/under estimation and their errors.
• Page 10: “Development of thematic maps” section. This section appears to be from the previous reports, and it is not from your study results. So, it is unnecessary for presenting here. It is only can be used for Study Area after significantly summarizing.
• Page 11: “The agricultural land quality map was constructed by overlaying seven thematic maps using ArcGIS software.” How did you overlay the maps. What are the weights you used for every map. How did you determine the weights. These are not clear.
• Table 6: it is unnecessary to present this information for every single LMU. Summarize them in a paragraph.
• Figure 3: the maps are not clear and presentable enough. The legends are not readable. Use the higher quality of the maps.
• Page 13: “Results of Developing the Crop Development Orientation Map for An Duong District” the land suitability analysis is unclear.
• Discussion section: this section includes general information that is mostly derived from the reports that you used, and it is not derived from your study results. In addition, in this section the methodology and results must be compared with previous studies.
• Conclusion section: this section is weak and does not present the novelty of this study. In this section, the highlighted findings must be presented.

Author Response

Dear Reviewer,

Thank you for taking the time to contribute to our manuscript. After reviewing your feedback, we have revised the draft of the article. Please see the attached files.

Best regards,

Son

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

This study investigates the use of GIS technology for soil quality management and agricultural planning in Vietnam’s Red River Delta. It develops a detailed soil quality map and evaluates crop suitability, proposing a strategy focused on rice, vegetables, and flowers for sustainable development. However, it has data limitations, insufficient consideration of farmer involvement, insufficient model validation, and the absence of long-term monitoring plans, all of which undermine the study’s applicability and robustness. Specific comments are as follows:

1. The abstract description is too general, lacks quantitative detail, and does not clearly articulate the study’s innovation points. In particular, as a common method, GIS needs to state where the innovation points are clearly. Moreover, the study area is small. This area cannot represent Vietnam’s overall situation. Then, the typicality and representativeness of this region are debatable.
2. The last paragraph of the introduction should clearly indicate what exactly the study needs to address.
3. Do the 96 surface soil samples reflect conditions in the study area?
4. Table 1 lists 11 soil quality indicators, and the test methods for these indicators need to be specific, not just the test standard. Moreover, what are the criteria for these indicators to be selected as soil quality indicators? Some indicators are physical and chemical properties, while others are heavy metal content, and these cannot be collectively referred to as soil quality parameters.
5. All the indicators displayed on the GIS graphs have different resolutions, and the authors use interpolation to fill in missing indicators, which introduces partial randomness. Moreover, how different resolutions are displayed in the same layer also needs to be expressed in the article. In addition, the consistent acquisition time of all samples is also a key factor affecting subsequent analysis.
6. Table 5 can be simplified without listing all the maximum, minimum, mean, and standard deviation information.
7. What is the significance of Table 6?
8. Figure 3 is unclear, and the display’s meaning is unclear.
9. The research results were analyzed in two aspects, but the implications, shortcomings, and future research suggestions were not addressed.
10. The number of references is too small, and the authors have limited knowledge of the literature in this field, so it is necessary to supplement it with the latest research.

Author Response

Dear Reviewer,

Thank you for taking the time to provide feedback on our draft. Please see our editorial explanations in the attached file.

Best regards,

Son

Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors

Summary of the Paper

The manuscript presents a GIS-based framework to support soil quality assessment and crop development planning in An Duong District (Red River Delta, Vietnam). The authors collected secondary environmental data, performed field surveys, and analysed 96 soil samples. Using ArcGIS overlay methods, they created seven thematic maps and produced a soil quality map with 47 land mapping units. Based on land suitability analysis, the study identifies rice, vegetables, and flowers as priority crops to support sustainable agricultural planning and food security. The paper aims to show how GIS tools can assist local decision-making for agricultural development under pressures from urbanization and climate change.

Major comments

Section 1: the manuscript explains context well but the research gap is not clearly defined. The authors must clarify what is new compared with previous GIS suitability studies in Vietnam and whether the novelty concerns methodology, spatial scale, or decision framework. Without this clarification, the scientific contribution appears limited.

Section 3.4: the MEC (Multi-Evaluation Criteria) process is mentioned but not described mathematically: no weighting scheme or criteria scoring is explained and no equation or workflow details for overlay analysis. Please include: criteria weights, decision rules, raster resolution, GIS projection system, and classification thresholds. Currently, another researcher cannot reproduce the results.

Section 3.3: 96 samples are collected, but no sampling strategy (random, stratified, grid) is described; no map of sampling locations and no clear depth definition beyond “topsoil”. This weakens methodological rigor.

Section 3.4: the thresholds for S1, S2, S3, N classes are presented but without references. The authors must justify the source of thresholds (FAO? national standards? expert judgment) and why the same “Not suitable” percentage appears for multiple crops (12.34%). This may indicate a methodological bias or a rounding issue.

Section 4.2 says agricultural land is 4,757.4 ha, while Table 6 total equals 4,753.82 ha.
The authors must explain the difference.

Table 5 reports CEC in ldl/100g soil, but the discussion uses cmol(+)/kg, therefore the units must be consistent. The discussion on heavy metals implies that they are all within permissible values, but Pb max = 175.10 mg/kg is above the threshold value of 70 mg/kg, which is a critical issue that requires clarification.

Section 5: repetition of the results from the earlier stages, with policy statements. To be included: comparison with the results from other studies, uncertainty analysis, limitations of the GIS approach.

Minor comments

 “Abtracts” could be “Abstract”.

Section 2 (last row): “asa whole” could be “as a whole”.

“Land quality map”, “soil quality map”, and “agricultural land quality map” are used interchangeably. Please standardize terminology.

Figure 2 workflow is useful but resolution appears low.

Table 3: “Vàn thấp” appears in English table (probably Vietnamese word).

Section numbering: duplicated “3.3” section.

Author Response

Dear Reviewer,

Thank you for taking the time to provide feedback on our draft. Please see our editorial explanations in the attached file.

Best regards,

Son

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The authors addressed all comments and considerations satisfactorily.

Reviewer 3 Report

Comments and Suggestions for Authors

The authors have made detailed revisions, which could be accepted for publication.

Reviewer 4 Report

Comments and Suggestions for Authors

Dear Authors,

Thank you for sending in a revised version of your manuscript together with a detailed cover letter addressing the comments.

I have carefully reviewed your revisions and am now very happy to inform you that the changes you have addressed do indeed satisfy all the comments I raised.

Congratulations and good luck on the publishing of your work.

Best regards.