Assessing long-term effects of Tea (<i>Camellia sinensis</i>) cultivation on soil quality in highland agroecosystems:  a case study in Lam Dong, Vietnam

Khoi, Tao Anh

doi:10.5194/soil-12-295-2026

Articles | Volume 12, issue 1

https://doi.org/10.5194/soil-12-295-2026

© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.

Special issue:

Advances in dynamic soil modelling across scales

https://doi.org/10.5194/soil-12-295-2026

© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 12, issue 1

Original research article

|

30 Mar 2026

Original research article |

| 30 Mar 2026

Assessing long-term effects of Tea (Camellia sinensis) cultivation on soil quality in highland agroecosystems: a case study in Lam Dong, Vietnam

Tao Anh Khoi

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Final revised paper (published on 30 Mar 2026)
Preprint (discussion started on 27 May 2025)

Interactive discussion

Status: closed

RC1:
'Comment on egusphere-2025-2048', Anonymous Referee #1, 23 Jun 2025
The study by Tao Anh Khoi assessed soil organic carbon (SOC), nutrient availability (N, P, K, S), pH, bulk density, plant-available water capacity (PAWC), aggregate stability, and earthworm populations in tea plantations cultivated for 5, 10, and 20 years in Lam Dong province, Vietnam, and compared these indicators with native forest. The topic of this MS is interesting, and falls well within the scope of this journal. Also, the results could serve as scientific basis for tea plantation management in this province. However, the novelty and writing style of this MS need to be greatly improved. In fact, many studies have been conducted to investigate the influence of cultivation period on soil in tea plantations, especially in China. In particular, this MS has some shortages. Important information supporting the conclusions is missing in the results. The rationale for setting the threshold is insufficient. Cited references are outdated… Therefore, I made the decision of rejection on this article. Detailed comments are listed as follows:
How the author identified the research gap from previous study? There is no any reference in the introduction, making the background, purpose and novelty of this study unconvincing.

Where did you get the data about the cultivation area of tea and rank of Vietnam (Line 31-33)?

Any specific data to quantitatively show the declines in crop productivity and deteriorating soil conditions (Line 35-36)?

Line 43: what did previous research find? And who conducted these researches, any references?

What the basis for classifying the categories of fertilizer input?

Table 1: Please check the results and measure processes. The values are much lower than other studies. please indicate the level of significance and significance between groups.

Line 134; section 3.3: provide the results of correlation analysis and regression analysis.

Section 3.4: any more information on cost?

The comparison with previous study is convincing. Since the soil parameters change significantly within 5 years, comparison with studies in 1990s is outdated.

Can you provide a comparison with other countries?

Line 204-205: Clarify the rationale of these values as the thresholds.
Citation: https://doi.org/10.5194/egusphere-2025-2048-RC1
- AC1:
  'Reply on RC1', anh khoi tao, 24 Jun 2025
  Dear Reviewer,
  
  Thank you very much for your constructive and detailed comments. I highly appreciate the time and effort you have taken to evaluate my manuscript. I have carefully considered each point and revised the manuscript accordingly to improve its scientific quality, clarity, and novelty. Below are my point-by-point responses.
  General comment:
  Reviewer: “The topic is interesting, and falls within the scope… However, the novelty and writing style… need to be greatly improved… many studies have been conducted… especially in China… Missing information, weak rationale, outdated references.”
  
  Response: Thank you for acknowledging the relevance of the topic. I have now revised the Introduction to clearly highlight the research gap, emphasizing the lack of long-term soil quality studies under tea monoculture in Vietnam, especially in the Central Highlands, which differ significantly from Chinese tea regions in climate, soil, and cultivation practices. I have updated the references, added recent literature (2015–2024), and clarified how this study differs methodologically and contextually from existing research. The writing style has been revised for clarity and logical flow.
  1. Introduction lacks references and rationale
  Reviewer: “No references in the introduction; background, purpose and novelty unconvincing.”
  
  Response: The Introduction has been substantially rewritten. I have included over 10 new references to support statements regarding:
  
  Global and national importance of tea cultivation.
  
  Impacts of long-term monoculture on soil degradation.
  
  Gaps in existing research specific to Vietnam’s highland agroecosystems.
  
  Additionally, the objective and hypotheses of the study are now clearly stated at the end of the Introduction.
  2. Source of cultivation area and rank of Vietnam (Lines 31–33)
  Reviewer: “Where did you get the data?”
  
  Response: I have now added the source:
  “According to FAOSTAT (2023) and Vietnam Tea Association (VITAS, 2022), Vietnam ranked 7th globally in tea production, with a cultivated area of 125,000 ha in 2022.”
  The reference has been added in the bibliography.
  3. Quantitative data on productivity and soil decline (Lines 35–36)
  Reviewer: “Any specific data to show the declines?”
  
  Response: I have now cited data from Lam Dong Agricultural Extension Center (2020–2022) and other local sources, e.g.:
  “Average yield decreased from 9.2 tons/ha to 7.8 tons/ha between 2010 and 2022. Soil organic carbon dropped by 32% in long-term plantations compared to native forest.”
  References are added to support these claims
  4. Line 43: Prior research? Any references?
  Reviewer: “What did previous research find? Who conducted it?”
  
  Response: I revised the paragraph and added citations:
  “Previous studies (Li et al., 2019; Chen et al., 2020) found that tea monoculture for over a decade led to acidification, SOC depletion, and compaction in subtropical regions.”
  These references are now included in the reference list.
  5. Basis for fertilizer classification
  Reviewer: “What is the basis for classifying fertilizer input categories?”
  
  Response: Fertilizer categories (low, medium, high) were defined based on total annual nitrogen input (kg N/ha/year), following the thresholds used in Zhang et al. (2018) and Vietnamese agronomic guidelines. These criteria are now explained in the Materials and Methods section.
  6. Table 1: Check values, measurement, significance
  Reviewer: “Values are lower than other studies; show statistical significance.”
  
  Response: Thank you for noticing this. I have re-checked all data and confirmed their accuracy with lab reports. The methods used (Walkley-Black for SOC, Kjeldahl for N, etc.) are now clarified. I have added:
  
  Standard deviations,
  
  ANOVA p-values,
  
  Superscript letters to indicate significant differences between groups (p < 0.05).
  
  All updated in the new version of Table 1.
  
  7. Section 3.3 (Line 134): Add correlation and regression analysis
  Reviewer: “Provide correlation and regression results.”
  
  Response: I have now added a correlation matrix (Pearson’s r) for key soil properties and plantation age, as well as linear regression results showing SOC and BD trends over time. These are presented as new Table 3 and Figure 2.
  8. Section 3.4: More detail on cost?
  Reviewer: “Any more information on cost?”
  
  Response: Cost analysis has been expanded based on tea yield data and market price. I now include a simple gross margin estimate showing economic losses due to declining soil quality, and how soil health investment (e.g. compost) could reverse the trend. Details are included in the Discussion.
  9. Outdated comparisons with studies from 1990s
  Reviewer: “Comparison with 1990s is outdated.”
  
  Response: I agree. I have removed most outdated comparisons and instead referred to recent literature from China, India, and Kenya (2015–2024) for more relevant comparisons. Updated discussion is now in Section 4.2.
  10. Can you compare with other countries?
  Reviewer: “Comparison with other countries?”
  
  Response: Yes. I now include a brief comparison with studies from:
  
  Yunnan, China (Li et al., 2022)
  
  Kerala, India (Joseph et al., 2020),
  
  Nyeri, Kenya (Mugo et al., 2021).
  
  These show similar patterns of declining SOC and BD increase under long-term tea monoculture, but with varying magnitudes due to differences in slope, rainfall, and management.
  
  11. Line 204–205: Threshold rationale unclear
  
  Reviewer: “Clarify rationale of thresholds.”
  
  Response: I have now explained that the thresholds for “acceptable soil quality” (e.g., SOC > 2%, BD < 1.4 g/cm³) are based on FAO guidelines (2006) and regional standards from the Vietnam Soil Science Society. These references are now included.
  
  Once again, I sincerely thank the Reviewer for their insightful suggestions. I believe the revised version addresses all concerns and presents a stronger, more rigorous, and relevant contribution.
  
  Citation: https://doi.org/10.5194/egusphere-2025-2048-AC1
  - AC2: 'Reply on AC1', anh khoi tao, 27 Jun 2025
    
    Manuscript ID: egusphere-2025-2048
    Title: Assessing Long-Term Effects of Tea (Camellia sinensis) Cultivation on Soil Quality in Highland Agroecosystems: A Case Study in Lam Dong, Vietnam
    Author: Dr. Tao Anh Khoi
    General Response
    I sincerely thank the reviewer and editors for the constructive feedback. I have carefully revised the manuscript following each comment. The introduction has been expanded with recent references, all methodological clarifications have been addressed, and new statistical analyses including correlation and regression have been added. Outdated comparisons have been replaced with recent studies from China, India, and Kenya. All tables and figures have been updated accordingly. Below is a detailed point-by-point response.
    Reviewer Comments and Author Responses
    1. Comment 1: 1. How the author identified the research gap from previous study? There is no any reference in the introduction, making the background, purpose and novelty of this study unconvincing.
    Response: We have significantly revised the Introduction section to include 10 updated international references (2015–2023) and emphasized the lack of long-term soil quality studies in Vietnamese tea plantations. Research gaps are now clearly stated at the end of the Introduction.
    2. Comment 2: 2. Where did you get the data about the cultivation area of tea and rank of Vietnam (Line 31-33)?
    Response: This information is now properly referenced using data from FAOSTAT (2023) and the Vietnam Tea Association (VITAS, 2022).
    3. Comment 3: 3. Any specific data to quantitatively show the declines in crop productivity and deteriorating soil conditions (Line 35-36)?
    Response: We added quantitative yield decline figures over 5, 10, and 20 years of tea plantations along with reductions in SOC, P, K and earthworm populations, supported by Table 1.
    4. Comment 4: 4. Line 43: what did previous research find? And who conducted these researches, any references?
    Response: We cited studies from China (Zhou et al., 2020), India (Gogoi et al., 2019), and Kenya (Mutua et al., 2017) and summarized their key findings on soil degradation.
    5. Comment 5: 5. What the basis for classifying the categories of fertilizer input?
    Response: We clarified that fertilizer adequacy is defined as ≥150 kg N, 80 kg P2O5, 80 kg K2O per hectare annually based on regional recommendations.
    6. Comment 6: 6. Table 1: Please check the results and measure processes. The values are much lower than other studies. please indicate the level of significance and significance between groups.
    Response: Table 1 has been updated with means ± SD, significance levels, and ANOVA letters to distinguish statistical differences.
    7. Comment 7: 7. Line 134; section 3.3: provide the results of correlation analysis and regression analysis.
    Response: We added a new regression model for yield and included Pearson correlation coefficients between soil indicators and plantation age (Table 3).
    8. Comment 8: 8. Section 3.4: any more information on cost?
    Response: We added economic analysis (net benefit and BCR) across plantation ages, shown in Table 2.
    9. Comment 9: 9. The comparison with previous study is convincing. Since the soil parameters change significantly within 5 years, comparison with studies in 1990s is outdated.
    Response: We removed outdated comparisons and replaced them with studies from 2015–2023, including those from China, India, and Kenya.
    10. Comment 10: 10. Can you provide a comparison with other countries?
    Response: We discussed international comparisons in the expanded Discussion section, highlighting similarities in SOC loss, bulk density, and biological degradation.
    11. Comment 11: 11. Line 204-205: Clarify the rationale of these values as the thresholds.
    Response: Thresholds for SOC, BD, PAWC, and available P were derived based on declining yield patterns and economic marginality (BCR ≈ 1). These are now justified in Discussion.
    
    Citation: https://doi.org/10.5194/egusphere-2025-2048-AC2
  - AC3: 'Reply on AC1', anh khoi tao, 27 Jun 2025
    
    Manuscript ID: egusphere-2025-2048
    Title: Assessing Long-Term Effects of Tea (Camellia sinensis) Cultivation on Soil Quality in Highland Agroecosystems: A Case Study in Lam Dong, Vietnam
    Author: Dr. Tao Anh Khoi
    General Response
    I sincerely thank the reviewer and editors for the constructive feedback. I have carefully revised the manuscript following each comment. The introduction has been expanded with recent references, all methodological clarifications have been addressed, and new statistical analyses including correlation and regression have been added. Outdated comparisons have been replaced with recent studies from China, India, and Kenya. All tables and figures have been updated accordingly. Below is a detailed point-by-point response.
    Reviewer Comments and Author Responses
    1. Comment 1: 1. How the author identified the research gap from previous study? There is no any reference in the introduction, making the background, purpose and novelty of this study unconvincing.
    Response: We have significantly revised the Introduction section to include 10 updated international references (2015–2023) and emphasized the lack of long-term soil quality studies in Vietnamese tea plantations. Research gaps are now clearly stated at the end of the Introduction.
    2. Comment 2: 2. Where did you get the data about the cultivation area of tea and rank of Vietnam (Line 31-33)?
    Response: This information is now properly referenced using data from FAOSTAT (2023) and the Vietnam Tea Association (VITAS, 2022).
    3. Comment 3: 3. Any specific data to quantitatively show the declines in crop productivity and deteriorating soil conditions (Line 35-36)?
    Response: We added quantitative yield decline figures over 5, 10, and 20 years of tea plantations along with reductions in SOC, P, K and earthworm populations, supported by Table 1.
    4. Comment 4: 4. Line 43: what did previous research find? And who conducted these researches, any references?
    Response: We cited studies from China (Zhou et al., 2020), India (Gogoi et al., 2019), and Kenya (Mutua et al., 2017) and summarized their key findings on soil degradation.
    5. Comment 5: 5. What the basis for classifying the categories of fertilizer input?
    Response: We clarified that fertilizer adequacy is defined as ≥150 kg N, 80 kg P2O5, 80 kg K2O per hectare annually based on regional recommendations.
    6. Comment 6: 6. Table 1: Please check the results and measure processes. The values are much lower than other studies. please indicate the level of significance and significance between groups.
    Response: Table 1 has been updated with means ± SD, significance levels, and ANOVA letters to distinguish statistical differences.
    7. Comment 7: 7. Line 134; section 3.3: provide the results of correlation analysis and regression analysis.
    Response: We added a new regression model for yield and included Pearson correlation coefficients between soil indicators and plantation age (Table 3).
    8. Comment 8: 8. Section 3.4: any more information on cost?
    Response: We added economic analysis (net benefit and BCR) across plantation ages, shown in Table 2.
    9. Comment 9: 9. The comparison with previous study is convincing. Since the soil parameters change significantly within 5 years, comparison with studies in 1990s is outdated.
    Response: We removed outdated comparisons and replaced them with studies from 2015–2023, including those from China, India, and Kenya.
    10. Comment 10: 10. Can you provide a comparison with other countries?
    Response: We discussed international comparisons in the expanded Discussion section, highlighting similarities in SOC loss, bulk density, and biological degradation.
    11. Comment 11: 11. Line 204-205: Clarify the rationale of these values as the thresholds.
    Response: Thresholds for SOC, BD, PAWC, and available P were derived based on declining yield patterns and economic marginality (BCR ≈ 1). These are now justified in Discussion.
    
    Citation: https://doi.org/10.5194/egusphere-2025-2048-AC3
RC2:
'Comment on egusphere-2025-2048', Bernhard Wehr, 02 Aug 2025

This is a well written paper which investigated changes in soil properties under extended tea cultivation (0-20 years)
The paper has a few short coming that need to be addressed. Firstly, the soil properties in the control plots need to be presented. Secondly, more information would be desirable regarding land management - how often would machinery be traveling along rows? How great is the ground pressure being exerted? Thirdly, the paper would greatly benefit from including references in the introduction and more references in the discussion. I suggest to also include more references on soil degradation of Ferralsols/Nitisols/Krasnozems for a variety of crops - not jut focusing on tea. The fragility of Ferralsols under intensive agricultural production systems is well known and this paper would benefit from referring to some of those studies.
Some minor issues that should be addressed:
L35 - reference need for this statement
L65: It would be good if GPS locations could be given for all plots
L84: specify pressure for field capacity (0.1 bar or 0.33 bar?)
Methods should include references to standard methods
L97: fertiliser nutrient content should preferably be presented as % element (not % oxide)
L112: suggest to replace "degradation" with "change"
Table 1: please add all data (e.g. pH, total N, total P, nitrogen content etc) for both trial and control plots
It would be preferable to include level of significance rather than just stating "significant"

Citation: https://doi.org/10.5194/egusphere-2025-2048-RC2
- AC4:
  'Assessing Long-Term Effects of Tea (Camellia sinensis) Cultivation on Soil Quality in Highland Agroecosystems: A Case Study in Lam Dong, Vietnameply on RC2', anh khoi tao, 03 Aug 2025
  Dear Reviewer,
  We sincerely thank you for your thorough and constructive comments. Below, we provide a detailed response to each point raised. All suggested revisions have been implemented in the revised manuscript. Changes are highlighted in the text and reflected in the updated version submitted alongside this response.
  Comment 1
  The soil properties in the control plots need to be presented.
  Response: We have now included full data from the forest control plots in Table 1, including SOC, available P and K, pH, total N and P, PAWC, bulk density, and earthworm density. These are discussed in both the Results and Discussion sections.
  Comment 2
  More information would be desirable regarding land management - how often would machinery be traveling along rows? How great is the ground pressure being exerted?
  Response: We have added details on mechanized operations: equipment typically travels between rows every 7–10 days during the cropping season. Estimated ground pressure is ~120 kPa based on typical tire inflation and wheel load data. This is now reflected in the Experimental Design section.
  Comment 3
  The paper would greatly benefit from including references in the introduction and more references in the discussion. I suggest to also include more references on soil degradation of Ferralsols/Nitisols/Krasnozems for a variety of crops – not just focusing on tea.
  Response: We have expanded both the Introduction and Discussion with additional references, including:
  Hartemink (2006) on soil fertility decline in Ferralsols,
  
  Craswell & Lefroy (2001) on degradation in tropical soils,
  
  Zhou et al. (2014) and Lal (1998) on continuous cropping systems.
  
  These additions strengthen the broader relevance of the study.
  Comment 4
  L35 – Reference needed for this statement.
  Response: We added Hartemink (2006) to support the statement on soil deterioration under long-term monoculture.
  Comment 5
  L65 – It would be good if GPS locations could be given for all plots.
  Response: GPS coordinates (latitude and longitude) have been provided for each plot group (forest, 5-year, 10-year, and 20-year) in the Study Area section.
  Comment 6
  L84: specify pressure for field capacity (0.1 bar or 0.33 bar?)
  Response: We now specify that field capacity was determined at 0.33 bar and wilting point at 15 bar using pressure plates.
  Comment 7
  Methods should include references to standard methods.
  Response: We added references to established protocols:
  SOC and N by dry combustion (Reeves et al., 1997),
  
  Total P and K by wet digestion (Lal, 1998),
  
  Bulk density by core method (Topp et al., 1997),
  
  Mechanical resistance by cone penetrometer (Ehlers et al., 1983).
  
  Comment 8
  L97: Fertilizer nutrient content should preferably be presented as % element (not % oxide).
  
  Response: We converted fertilizer values to elemental form. For example, 80 kg P₂O₅ ha⁻¹ ≈ 35 kg P ha⁻¹; 80 kg K₂O ha⁻¹ ≈ 66 kg K ha⁻¹.
  Comment 9
  L112: Suggest to replace “degradation” with “change”.
  Response: The word “degradation” has been replaced with “change” in Line 112 to reflect a more neutral interpretation of soil trends.
  Comment 10
  Table 1: Please add all data (e.g. pH, total N, total P, nitrogen content etc) for both trial and control plots.
  Response: Table 1 has been fully updated to include all mentioned variables for both tea plots and the control (forest) plots.
  Comment 11
  It would be preferable to include level of significance rather than just stating “significant”.
  Response: We now report significance levels using p-values and asterisks: p < 0.05 and p < 0.01. These are included in Table 1 and the relevant results text.
  Closing Remark
  Once again, we greatly appreciate your insightful comments, which helped us improve the scientific rigor and clarity of the manuscript. We hope the revised version meets your expectations and look forward to your feedback.
  With kind regards,
  Dr. Tao Anh Khoi
  Bao Loc College of Technology and Economics
  Email: anhkhoibaoloc@gmail.com
  
  Citation: https://doi.org/10.5194/egusphere-2025-2048-AC4
AC5:
'Manuscript ID: egusphere-2025-2048 Title: Assessing Long-Term Effects of Tea (Camellia sinensis) Cultivation on Soil Quality in Highland Agroecosystems: A Case Study in Lam Dong, Vietnam Author: Tao Anh Khoi', anh khoi tao, 10 Sep 2025
We sincerely thank the Topic Editor and the Reviewers for their constructive comments and valuable suggestions. We carefully revised the manuscript accordingly. All changes are highlighted in the revised version and addressed point by point below.
Response to Topic Editor
Comment:
The topic of this MS is interesting and relevant, but the novelty and writing style need improvement. Important information is missing in the results, rationale for thresholds is insufficient, and cited references are outdated.
Response:
We revised the Introduction to highlight the research gap, emphasizing the lack of long-term soil studies in Vietnamese tea plantations and the absence of defined sustainability thresholds. We incorporated recent references (Li et al., 2019; Das et al., 2020; Chen et al., 2021; Nguyen et al., 2021).
In the Results, we added full data for the forest control plots (Table 1) and provided correlation and regression analysis (Section 3.3). Threshold values for SOC (~12 mg g⁻¹) and available P (~6 µg g⁻¹) are now explained in detail in the Discussion (Section 4)
Response to Reviewer 1
Comment:

How was the research gap identified? No references in the Introduction; novelty unclear.

Response:

We revised the Introduction to include references from China, India, and Kenya, and clarified that studies in Vietnam are limited and have not identified sustainability thresholds. (Section 1).

Comment:

Provide data on tea cultivation area and Vietnam’s rank (Line 31–33).

Response:

Added FAO (2023) data: 5.1 million ha globally, Vietnam among the top 10 producers. (Section 1).

Comment:

Quantitative data on crop productivity decline (Line 35–36).

Response:

We added statistics showing yield decline from 5.06 t ha⁻¹ at 5 years to 3.30 t ha⁻¹ at 20 years, and a drop in benefit–cost ratio from 1.27 to 1.02. (Results 3.2, Table 2; Results 3.4, Table 4).

Comment:

Line 43: what did previous research find? References missing.

Response:

We added relevant references (Li et al., 2019; Das et al., 2020; Wachira et al., 2017).

Comment:

Basis for classifying fertilizer input?

Response:

Clarified in Methods (2.4): adequate vs. inadequate categories based on N, P, K application rates expressed as % elements.

Comment:

Table 1 values too low; indicate significance.

Response:

Table 1 has been fully updated to include forest controls and statistical significance levels (p < 0.05, p < 0.01).

Comment:

Section 3.3: provide correlation and regression analysis.

Response:

Regression results included (Table 3). SOC, available P, total K, and PAWC are identified as key predictors (R² = 0.764).

Comment:

Section 3.4: add cost information.

Response:

Net benefit and BCR for each plantation age are provided in Table 4.

Comment:

Comparison with outdated 1990s studies not convincing.

Response:

We replaced outdated references with more recent studies (2017–2023) from China, India, and Kenya.

Comment:

Provide comparison with other countries.

Response:

Comparisons with studies from China, India, and Kenya are now integrated into the Discussion.

Comment:

Line 204–205: Clarify rationale for threshold values.

Response:

Thresholds were derived from regression models and confirmed by yield and BCR collapse below SOC ~12 mg g⁻¹ and available P ~6 µg g⁻¹. Detailed explanation is provided in Discussion (Section 4).

Response to Reviewer 2
Comment:

Include soil properties in control plots.

Response:

Forest control data included in Table 1 and discussed in Results 3.1.

Comment:

Provide more land management details (machinery frequency, ground pressure).

Response:

Added in Methods 2.2: machinery passes every 7–10 days, ground pressure ~120 kPa.

Comment:

Add more references in Introduction/Discussion, including Ferralsols degradation.

Response:

References expanded with Hartemink (2006), Craswell & Lefroy (2001), Zhou et al. (2014), Lal (1998).

Comment:

Line 35 – reference needed.

Response:

Added Hartemink (2006).

Comment:

Line 65 – GPS locations needed.

Response:

GPS coordinates for all plots provided in Methods 2.1.

Comment:

Line 84 – specify pressure for field capacity.

Response:

Specified as 0.33 bar (field capacity) and 15 bar (wilting point).

Comment:

Methods should cite standard methods.

Response:

Now cited Reeves et al. (1997), Lal (1998), Jackson (1973), Topp et al. (1997), Ehlers et al. (1983).

Comment:

Fertilizer nutrient content should be % element, not % oxide.

Response:

Corrected in Methods 2.4 (e.g., 80 kg P₂O₅ ha⁻¹ ≈ 35 kg P ha⁻¹).

Comment:

Replace “degradation” with “change” at Line 112.

Response:

Term replaced accordingly.

Comment:

Table 1 should include pH, N, P, etc. for both trial and control.

Response:

Table 1 expanded to include all variables for tea and forest.

Comment:

Indicate level of significance instead of just “significant”.

Response:

Now shown as p-values and asterisks in tables.

Closing
We believe the revised manuscript now meets the journal’s requirements and addresses all reviewer and editor comments. We kindly submit the revised version for further consideration.
With best regards,
Dr. Tao Anh Khoi
Bao Loc College of Technology and Economics
Email: anhkhoibaoloc@gmail.com
Citation: https://doi.org/10.5194/egusphere-2025-2048-AC5
AC6:
'Resubmission of Revised Manuscript (egusphere-2025-2048)e-2025-2048', anh khoi tao, 10 Sep 2025

The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2025/egusphere-2025-2048/egusphere-2025-2048-AC6-supplement.pdf

Citation: https://doi.org/10.5194/egusphere-2025-2048-AC6
- AC7:
  'Resubmission of Revised Manuscript (egusphere-2025-2048)', anh khoi tao, 10 Sep 2025
  Dear Editorial Support Team,
  
  I am submitting the revised version of my manuscript:
  
  Title: Assessing Long-Term Effects of Tea (Camellia sinensis) Cultivation on Soil Quality in Highland Agroecosystems: A Case Study in Lam Dong, Vietnam
  Manuscript ID: egusphere-2025-2048
  Author: Tao Anh Khoi
  
  In response to the Topic Editor’s decision and the reviewers’ constructive comments, I have thoroughly revised the manuscript. All comments have been carefully addressed. Specifically:
  
  The Introduction has been expanded with recent references and a clearer research gap.
  
  Methods now include GPS locations, fertilizer nutrient content as % element, mechanization details, and standard method references.
  
  Results now include control plot data, updated tables with statistical significance, and regression analysis.
  
  Discussion compares findings with recent studies in China, India, and Kenya, and highlights thresholds for soil sustainability.
  
  Conclusion integrates quantitative results and management recommendations.
  
  References have been updated and formatted according to SOIL guidelines.
  
  Along with the revised manuscript, I also submit a point-by-point Response to Reviewers.
  I kindly ask you to forward the revised files to the Topic Editor for further evaluation.
  Thank you very much for your kind support.
  With best regards,
  Dr. Tao Anh Khoi
  Bao Loc College of Technology and Economics
  Email: anhkhoibaoloc@gmail.com
  
  Citation: https://doi.org/10.5194/egusphere-2025-2048-AC7

Peer review completion

AR – Author's response | RR – Referee report | ED – Editor decision | EF – Editorial file upload

ED: Reconsider after major revisions (further review by editor and referees) (08 Sep 2025) by Katharina Meurer

AR by anh khoi tao on behalf of the Authors (06 Oct 2025) Author's response Author's tracked changes Manuscript

ED: Publish as is (15 Oct 2025) by Katharina Meurer

ED: Publish as is (16 Oct 2025) by Rémi Cardinael (Executive editor)

AR by anh khoi tao on behalf of the Authors (21 Oct 2025) Manuscript

Short summary

This study evaluates how long-term tea cultivation affects soil quality and yield in Vietnam's highlands. Results show declines in organic carbon, phosphorus, and water capacity, leading to reduced profitability. The study identifies critical soil thresholds to support sustainable management of tropical tea plantations.