Comprehensive Assessment of the Correlation Between Ancient Tea Garden Soil Chemical Properties and Tea Quality

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Comprehensive Assessment of the Impact of Ancient Tea Garden Soil Properties on Tea Quality

Manuscript ID: horticulturae-3267048

The manuscript is well structured and nicely written. The Results and Discussion part is well written with the supporting data. However, having thoroughly reviewed the manuscript presented to me, I have some comments and suggestions, which I present below:

Major comments:

1.     The manuscript suffers from minor grammatical issues. Careful review and editing are necessary.

2.     The abbreviation and full forms were used inappropriately.

3.     The objective of this study is bit unclear and contradicts with the title. For example, soil properties and impact of heavy metals on tea quality and yield are completely different aspects. It is also not clear in the introduction that which soil properties will be considered in this study and why?

4.     What was the size of the study area for 27 samples? Specify the size of the study area of each site.

5.     As per my understanding the root length of most of the tea tree species goes up to 75 to 80 cm. Then why the soil samples were collected only from 40 cm depth? Moreover, mixing of top soil with bottom layer is not a good idea. It will be better to keep them separate for better management.

6.     I am bit confused about the unit of soil parameters presented in Table 2.

7.     The CV of many parameters are too high up to 70%. The CV with such a high value is not acceptable for any scientific publication.

8.     I am bit confused about the soil analysis data. In the materials the author mentioned that they mixed up the soil of 0-20 and 20-40 in one soil sample. They presented the soil chemical properties in one layer but they presented the heavy metals in two layer-why?

9.     The authors focused on soil chemical properties. Why the soil physical and biological properties were not considered? It will be better to specify the title to soil chemical properties instead of soil properties.

10.  It will be good to have a correlation among tea quality parameters and heavy metals separately.

 

Comments on the Quality of English Language

The manuscript suffers from minor grammatical issues. Careful review and editing are necessary

Author Response

The manuscript is well structured and nicely written. The Results and Discussion part is well written with the supporting data. However, having thoroughly reviewed the manuscript presented to me, I have some comments and suggestions, which I present below:

(1) The manuscript suffers from minor grammatical issues. Careful review and editing are necessary.

Modification instructions: Thank you for pointing out the grammatical issues in our manuscript. We have thoroughly proofread the entire document to ensure grammatical accuracy and clarity of expression. We believe that these efforts have significantly improved the quality of our article.

We have made the following revisions to the manuscript:

1. We conducted a comprehensive grammar and spelling check using professional language editing software.
2. We invited experienced peers to review the article to ensure the accuracy and consistency of the terminology used.
3. We reviewed the article sentence by sentence to ensure that each sentence is grammatically correct and clearly expressed.

We believe these modifications have addressed the concerns you raised and enhanced the overall quality of the manuscript. We sincerely appreciate your valuable feedback.

 

(2) The abbreviation and full forms were used inappropriately.

Modification instructions: Thank you for highlighting the concerns regarding the use of abbreviations and full terms in our manuscript. We have meticulously reviewed the entire document to ensure that all abbreviations are accompanied by their full forms at their initial mention, with the abbreviations provided in parentheses, and that they are used correctly and consistently throughout the subsequent text. Special attention has been given to the abbreviations of scientific terms, variables, and specific project names to guarantee their appropriate and uniform usage.

The following revisions have been made to the manuscript:

1. We have ensured that all abbreviations are explicitly defined with their full terms when first introduced, with the abbreviation in parentheses.
2. A thorough check of the entire text has been conducted to ensure that all abbreviations are used consistently in subsequent references.
3. For abbreviations that may cause confusion, we have added explanations or avoided their use to enhance the clarity of the article.

We believe these amendments will make the article clearer and more accessible, and we apologize for any confusion that may have arisen from the previous version. We greatly appreciate your valuable comments, which have helped us to improve the quality of our manuscript.

 

(3) The objective of this study is bit unclear and contradicts with the title. For example, soil properties and impact of heavy metals on tea quality and yield are completely different aspects. It is also not clear in the introduction that which soil properties will be considered in this study and why?

Modification instructions: Thank you for drawing our attention to the lack of clarity regarding the objectives of our study. We recognize the importance of clearly defining the research goals for the readers' comprehensive understanding of the paper. To address your concerns, we have made the following revisions to our manuscript:

1. Clarification of Research Objectives: We have rephrased the research objectives in the introduction to ensure alignment with the title and to more accurately reflect the scope and focus of the study.
2. Definition of Research Scope: We have specified the soil properties that this study will consider and explained the rationale behind selecting these properties. These properties were chosen due to their close relationship with tea quality and yield, and their potential susceptibility to heavy metal contamination.
3. Elucidation of Research Connections: We have further explained the interplay between soil properties and heavy metals in influencing tea quality and yield, clarifying how, although distinct aspects, they are interconnected within the context of this study.

We believe these modifications will render the purpose and significance of the research more transparent and apologize for any confusion caused by the previous version. We greatly appreciate your valuable feedback, which has significantly contributed to enhancing the quality of our manuscript.

 

(4) What was the size of the study area for 27 samples? Specify the size of the study area of each site.

Modification instructions: Thank you for your valuable feedback. Our study involved soil sampling in four regions of Tujie Town, Nanhua County. The areas of each study region are as follows:

1. The Changliangzi (CLZ) region spans an area of 3.43 hectares.
2. The Banpo (BP) region covers an area of 2.56 hectares.
3. The Xiaocun (XC) region encompasses an area of 2.84 hectares.
4. The Ganlongtan (GLT) region has an area of 3.04 hectares.

The selection of these areas was based on factors such as topography and the age of the tea gardens to ensure the representativeness of the samples. Soil samples from each region were collected through three randomly established plots, with nine "S" shaped sampling points in each plot, resulting in a total of 27 soil samples per study region. We agree that providing this information is crucial for understanding the scale of the study and the representativeness of the samples. We have detailed the size of each study region in Table 1 of the revised manuscript.

We appreciate your suggestion and hope that this information meets your requirements.

 

(5) As per my understanding the root length of most of the tea tree species goes up to 75 to 80 cm. Then why the soil samples were collected only from 40 cm depth? Moreover, mixing of top soil with bottom layer is not a good idea. It will be better to keep them separate for better management.

Modification instructions: We sincerely appreciate your meticulous review and valuable feedback on our study. You have rightly pointed out the need for further clarification regarding the depth of tea plant root systems, which is indeed a critical aspect of our research that requires more detailed discussion. In response to your suggestions, we have made the following revisions and clarifications to our manuscript:

1. Tea Plant Root Systems and Nutrient Absorption: Although tea plant root systems may extend to depths of 75 to 80 cm, the absorption of soil nutrients primarily occurs in the upper 0-40 cm soil layer. This is largely due to the higher organic matter content and microbial activity in the topsoil, which provide abundant nutrients and moisture for tea plant growth.
2. Soil Management Practices in Tea Gardens: In the context of soil management in tea gardens, fertilization and soil amendment practices are typically concentrated in the 0-40 cm soil layer. This layer has the most direct impact on tea plant growth and development, which is why our soil sampling was also focused within this depth range.
3. Research Objectives and Sampling Depth Selection: One of the objectives of our study was to evaluate the impact of soil management practices on the quality of tea leaves in ancient tea gardens. Therefore, the depth of soil sampling we selected is more closely aligned with the practical needs of tea garden management, allowing for a more accurate assessment of the effects of soil management practices.

Regarding the issue of soil sample mixing, we conducted separate analyses for soil samples from the 0-20 cm and 20-40 cm layers to assess soil nutrients and heavy metal content. However, in the descriptive statistics for soil nutrients, we combined the soil samples from both depths for statistical analysis, rather than performing separate stratified analyses. This approach aims to enhance the transparency and rationality of our research findings, ensuring that our analysis comprehensively reflects the actual soil conditions.

We have made the corresponding revisions to the manuscript to ensure that the description of these key points is more precisely and clearly. We apologize for any confusion caused by the previous version and appreciate your valuable comments, which have helped us improve the quality of our manuscript.

Thank you for your feedback, and we look forward to receiving any further guidance and suggestions you may have.

 

(6) I am bit confused about the unit of soil parameters presented in Table 2.

Modification instructions: Thank you for your meticulous review and valuable comments. We understand that the unit expressions for the soil parameters in Table 2 may have caused some confusion. We will supplement the units for the parameters in Table 2 to ensure that all units for soil parameters are clearly defined and unambiguous.

We will update Table 2 in the revised manuscript and make sure that all units are clearly labeled to prevent any further confusion. We appreciate your valuable feedback and look forward to any further guidance and suggestions you may have.

 

(7) The CV of many parameters are too high up to 70%. The CV with such a high value is not acceptable for any scientific publication.

Modification instructions: Thank you for your meticulous review and valuable comments. We understand your concern regarding the high coefficient of variation (CV) values. We acknowledge that high CV values can impact the interpretation of data and the rigor of scientific research.

Before addressing your concerns, we would like to emphasize that soil environment has a significant impact on tea quality, and this field often experiences high variability. In fact, several studies have reported similar high CV values, reflecting the inherent variability of soil parameters in natural environments.

To further support our findings and demonstrate that high CV values can be acceptable in certain circumstances, we reviewed relevant literature and found the following studies that also reported similar high CV values:

1. Wang et al. (2022) found a high CV value of 91.46% for tea quality parameters. Article details: https://doi.org/10.3390/horticulturae8040278
2. Jin et al. (2014) also observed similar high CV values, with tea components exhibiting a high coefficient of variation up to 323.6%. Article details: https://doi.org/10.1021/jf5024559
3. Wang et al. (2010) observed similar high CV values, with β-carotene content in tea exhibiting a high coefficient of variation up to 81.5%. Article details: https://doi.org/10.1016/j.jfca.2009.01.016

Based on the support from these literature references, we believe that although the CV values are high, they are reasonable within the context of our study. We trust that with this additional literature support, our research findings are more robust and can provide valuable insights to the scientific community. We look forward to your further guidance and suggestions.

 

(8) I am bit confused about the soil analysis data. In the materials the author mentioned that they mixed up the soil of 0-20 and 20-40 in one soil sample. They presented the soil chemical properties in one layer but they presented the heavy metals in two layer-why?

Modification instructions: Thank you for your detailed examination and valuable feedback. Your question is very valid, and we understand that this may have caused some confusion. Regarding the different treatment methods for soil chemical properties and heavy metal analysis, our decisions were based on the following considerations:

1. Soil Chemical Property Analysis: For the chemical properties of the soil (such as pH, organic matter content, nutrient levels, etc.), we indeed conducted separate measurements for soil samples from the 0-20 cm and 20-40 cm layers. In the results section, we chose to combine the data from these two layers for analysis because we believe this provides a more comprehensive reflection of the overall soil fertility conditions. This approach helps us to offer a more integrated perspective to assess the nutritional value of the soil, thereby providing more comprehensive guidance for soil management in tea gardens.
2. Heavy Metal Analysis: For the analysis of heavy metal content, we opted to analyze the soil samples from the two layers separately. This is because the distribution of heavy metals in the soil can be influenced by various factors, including soil particle size, organic matter content, and soil pH. These factors may vary significantly across different soil depth layers, so separate analysis can more accurately reveal the distribution characteristics of heavy metals in the soil profile, as well as potential ecological risks.

We acknowledge that our original presentation may not have sufficiently explained this point, leading to confusion. We will clarify this in the revised manuscript and provide a detailed rationale for our decisions to ensure that readers can clearly understand our research methods and analysis processes.

Thank you again for your valuable feedback, and we look forward to any further guidance and suggestions you may have.

 

(9) The authors focused on soil chemical properties. Why the soil physical and biological properties were not considered? It will be better to specify the title to soil chemical properties instead of soil properties.

Modification instructions: Thank you for your valuable comments and for highlighting an important aspect of soil study. Indeed, our research focused primarily on the chemical properties of the soil, as our aim was to explore how these properties affect the quality of tea leaves in ancient tea gardens. We acknowledge that the physical and biological properties of the soil are also significant factors influencing the growth of tea plants and the quality of tea.

Regarding the reason for not considering the physical and biological properties of the soil:

1. Research Purpose and Scope: The main objective of this study was to assess the impact of soil chemical properties on the quality of tea leaves in ancient tea gardens. Therefore, we selected a series of chemical parameters directly related to tea quality as the focus of our research.
2. Resource and Time Constraints: While we recognize the importance of the physical and biological properties of the soil, due to limitations in resources and time, we were unable to include these properties in this study. We hope that future research will be able to expand into these areas.
3. Accuracy of the Title: Your suggestion to change the title to more accurately reflect our research focus is an excellent one. We will consider changing the title to "Comprehensive Assessment of the Correlation between Ancient Tea Garden Soil Chemical Properties and Tea Quality" to more accurately reflect the content of our study.

Thank you again for your valuable feedback, and we look forward to any further guidance and suggestions you may have.

 

(10) It will be good to have a correlation among tea quality parameters and heavy metals separately.

Modification instructions: Thank you for your suggestion. We are delighted to see your interest in the correlation between tea quality parameters and heavy metal content. In fact, we have conducted this analysis in our study, and the results are presented in Table 8.

In Table 8, we illustrate the Pearson correlation coefficients for the tea quality components, including tea polyphenols, free amino acids, soluble sugars, flavonoid glycosides, etc., with soil properties and heavy metal contents in the soil, such as cadmium, mercury, lead, chromium, and others. These analyses provide us with valuable insights into the potential impacts of heavy metal contamination on tea quality.

We recognize the importance of these correlation analyses in understanding the effects of soil heavy metal pollution on the safety and quality of tea. Therefore, we have also thoroughly discussed the implications of these correlation results in the discussion section, and explored their potential impacts on tea garden soil management and the safe production of tea.

We believe that these analyses and discussions enhance the value of our study and provide more comprehensive guidance for tea garden management. We hope that this information meets your requirements.

Thank you again for your valuable feedback, and we look forward to your further guidance and suggestions.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Dear Authors, 
the article entitled "Comprehensive Assessment of the Impact of Ancient Tea Garden Soil Properties on Tea Quality" covers an interesting topic. The study is well-designed, and the article is well-prepared. However, some improvement is needed:
1. Title: After carefully reading the article, I prefer to use the term of "Correlation" instead of "Impact"
2. Abstract: Please add the problem statement in the first sentence. 
3. Abstract: Please add the significant of the study
4. Introduction: There is still no explanation which research gap that the authors want to fill in among the existing literatures.
5. Table 1: Please add the GPS location of the sampling site for traceability
6. Statistical Analysis: Since this research have some variables and parameters, I recommend to analyse the result using PCA plots. The plots can represents the correlation among variables and parameters.
7. Table 5: Please do pivot (columns as row, and vice versa).
8. Discussion: Still lack of discussion on: (a)The possible mechanism of certain element can impact the composition of the tea; (b) Comparison between the results obtained in this study and the existing literatures.
9. Conclusion: Please add the limitation of this study, and thus based on the limitation please give recommendation for further research.

Author Response

Dear Authors,

the article entitled "Comprehensive Assessment of the Impact of Ancient Tea Garden Soil Properties on Tea Quality" covers an interesting topic. The study is well-designed, and the article is well-prepared. However, some improvement is needed:

(1) Title: After carefully reading the article, I prefer to use the term of "Correlation" instead of "Impact"

Modification instructions: Thank you for your valuable suggestion. We have carefully considered your feedback and agree that the term "Correlation" more accurately reflects the core focus of our study, which is to explore the relationship between the properties of ancient tea garden soils and tea quality. Therefore, we have decided to change the title of our article from "Comprehensive Assessment of the Impact of Ancient Tea Garden Soil Properties on Tea Quality" to "Comprehensive Assessment of the Correlation between Ancient Tea Garden Soil Properties and Tea Quality". We believe this modification will more clearly convey the focus of our research and align better with the content of the paper. Thank you again for your suggestion and support.

 

(2) Abstract: Please add the problem statement in the first sentence.

Modification instructions: Thank you for your suggestion. We have added a problem statement in the abstract, clearly stating that the purpose of our study is to explore the correlation between the properties of ancient tea garden soils and tea quality. This modification helps readers quickly grasp the core issue and significance of our research. We believe that this change makes the abstract more directly and clearly, better reflecting the motivation and objectives of our study. Thank you again for your valuable feedback. The added content is:

"Understanding the correlation between soil chemical properties and tea quality is essential for the comprehensive management of ancient tea gardens. However, the specific links between these factors in ancient tea gardens remain underexplored."

 

(3) Abstract: Please add the significant of the study

Modification instructions: Thank you for your insightful suggestion. We have augmented the abstract to include a statement of the significance of our research, explicitly highlighting the contribution of this study to understanding the relationship between the soil properties of ancient tea gardens and tea quality. Furthermore, we have underscored the pivotal guiding significance of these findings for enhancing tea quality and ensuring the sustainable cultivation of ancient tea gardens. We believe this addition renders the abstract more comprehensive, better showcasing the value of our research and its potential implications for agricultural practices. Thank you once again for your valuable feedback. The content added is:

"Insights from this study are crucial for optimizing soil management in ancient tea gardens, potentially improving tea quality and sustainability."

 

(4) Introduction: There is still no explanation which research gap that the authors want to fill in among the existing literatures.

Modification instructions: Thank you for your suggestion. We have supplemented the introduction with a discussion on the existing research gaps, clarifying the specific void that this study aims to fill. We have pointed out that while there is existing research on the impact of soil properties on the growth of tea plants and tea quality, studies on the relationship between the characteristics of ancient tea garden soils and key chemical components of tea are still limited. Particularly in the ancient tea gardens of Yunnan, these tea trees are highly valued for their unique historical and cultural significance, yet there are few reports on the relationship between soil and tea quality. By analyzing soil samples from four different regions in Nanhua County and exploring their influence on key chemical components in ancient tea garden teas, this study aims to provide a scientific basis for improving the quality of ancient tea garden teas through soil management. We believe this modification makes the introduction more complete, better highlighting the importance and novelty of this study. Thank you again for your valuable feedback.

 

(5) Table 1: Please add the GPS location of the sampling site for traceability

Modification instructions: Thank you for your suggestion. We have added the GPS location information, including longitude and latitude coordinates, for the sampling points in Table 1. This modification enhances the traceability of our study, allowing other researchers to easily locate and verify our sampling sites. We believe this addition will increase the transparency and reliability of our research. Thank you again for your valuable feedback.

 

(6) Statistical Analysis: Since this research have some variables and parameters, I recommend to analyse the result using PCA plots. The plots can represents the correlation among variables and parameters.

Modification instructions: We sincerely appreciate your valuable suggestion. We agree that Principal Component Analysis (PCA) is an effective data reduction technique that can reveal the contribution of original variables to the principal components, which is crucial for understanding the complex structure within the data. Following your advice, we have conducted PCA and integrated the results in the form of figures into the results section. These figures not only provide a visual representation of the data but also lay a solid foundation for further statistical analyses, such as Pearson correlation coefficient analysis. We believe that the supplementary figures will add depth to our study, making the interpretation of the data clearer and more intuitive for readers.

We are confident that with these additional analyses, our research will be more comprehensive in presenting the multi-dimensional characteristics of the data, while also providing readers with an easier-to-understand perspective on the data.

Thank you again for your suggestion, and we look forward to receiving further guidance and feedback from you.

 

(7) Table 5: Please do pivot (columns as row, and vice versa).

Modification instructions: Thank you for your suggestion. We have transposed Table 5, swapping the rows and columns, to improve the readability and clarity of the data. We believe this change will make it easier for readers to understand the information presented in the table. Thank you again for your valuable feedback.

 

(8) Discussion: Still lack of discussion on: (a)The possible mechanism of certain element can impact the composition of the tea; (b) Comparison between the results obtained in this study and the existing literatures.

Modification instructions: Thank you for your valuable feedback. We have expanded the discussion section to include a discussion on the possible mechanisms by which specific elements affect the composition of tea, as well as a comparison of the results of this study with existing literature.

The added content is as follows:

Tea polyphenols, free amino acids, soluble sugars, and flavonoid glycosides are the principal biochemical constituents of tea. They are not only key to the flavor profile and health benefits of tea but also crucial indicators for assessing tea quality [42]. The growth of tea plants relies on fertile soil, which provides the essential material basis for the plants. The nutritional supply in the soil, especially the availability of carbon (C), nitrogen (N), and phosphorus (P), directly affects the tea plant's absorption and utilization efficiency of these nutrients, thereby determining the formation of the main quality components in tea [10, 43, 44]. Nutrients such as N, P, and sulfur (S) are crucial for the growth of tea plants and the formation of tea quality [45]. These elements directly affect the synthesis of biochemical components in tea by participating in the metabolic pathways of tea plants. For instance, nitrogen is an essential element for the biosynthesis of tea polyphenols [46], while phosphorus and sulfur are involved in energy metabolism and the synthesis of secondary metabolites [47].

Under heavy metal stress, plants exude a variety of low molecular weight compounds, such as amino acids, organic acids, sugars, phenolics, and other secondary metabolites [53]. Heavy metals in the soil, such as Cd and Hg, affect tea quality by disrupting the normal metabolic pathways of tea plants. The stress of heavy metals may lead to the production of more antioxidants, such as tea polyphenols, to combat the toxicity of heavy metals, but excessively high levels of heavy metals can also be toxic to tea plants, affecting the quality and safety of tea. Soil organic matter plays an essential role in the plant-soil system regarding the availability of heavy metals by inducing changes in soil physicochemical properties and through its metal chelation capacity [54, 55]. The mobility and bioavailability of heavy metals like Cd, Cu, Pb, and Zn are modulated by the solubilizing action of OM and the concomitant formation of organometallic complexes [56]. Additionally, soil-borne heavy metals are critical determinants of the principal quality constituents in tea [57]. This study primarily focuses on the influence of Cd and Hg on the key quality components of tea, with Cd impacting the tea polyphenols and CG, and Hg affecting the concentrations of EC, GC, GCG, tea polyphenols, free amino acids, soluble sugars, and flavonoid glycosides. The underlying mechanisms of these interactions warrant further exploration. The research findings indicate variations in the extent of heavy metal contamination across the four research regions, with XC and BP exhibiting the highest levels of pollution. In the XC region, the risk of Cd contamination was considered moderate, while the other three regions were classified as low risk. In another study, Cd was identified as a primary source of pollution from phosphate fertilizers [58]. This could be attributed to the proximity of XC and BP to residential living areas.

Our research findings are consistent with existing literature on the impact of soil nutrients on tea quality. For instance, the study by Wen and Liu et al [59, 60] demonstrated a positive correlation between N and P content in the soil and the levels of tea polyphenols and caffeine in the tea leaves. Additionally, our study discovered a significant correlation between soil heavy metal contamination and tea quality parameters, a finding that echoes the results of Zhang et al. [61], both of which highlight the potential risks of soil heavy metal pollution to the quality and safety of tea. However, while our study explores the relationship between soil chemical properties and tea quality, it also considers the impact of soil heavy metal pollution, which has been less addressed in previous studies. Our results emphasize that in addition to focusing on the supply of soil nutrients in tea garden soil management, it is also necessary to pay attention to the control of heavy metal pollution to ensure the quality and safety of tea.

We believe that this additional discussion will provide a more comprehensive understanding of how soil properties can influence tea quality and offer a scientific basis for optimizing tea garden management to enhance the quality and safety of tea.

 

(9) Conclusion: Please add the limitation of this study, and thus based on the limitation please give recommendation for further research.

Modification instructions: Thank you for your suggestion. We have concisely outlined the limitations of this study in the conclusion section, including the limitations of sample size and the exclusion of soil physical and biological properties. Based on these limitations, we recommend that future studies expand the sample range and consider a broader range of soil characteristics to enhance the comprehensiveness of the research findings. Thank you again for your valuable feedback.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Thank you very much to the authors for addressing most of the issues raised. I think the quality of the manuscript has improved significantly to be consider for publication after minor changes. Still I am curious to know that why the authors collected 27 samples from each sampling area? Although the sampling area are quite different in size even larger by one ha than other. The sampling should be based on area of the sampling area not a fixed value.

Author Response

(1)Thank you very much to the authors for addressing most of the issues raised. I think the quality of the manuscript has improved significantly to be consider for publication after minor changes. Still I am curious to know that why the authors collected 27 samples from each sampling area? Although the sampling area are quite different in size even larger by one ha than other. The sampling should be based on area of the sampling area not a fixed value.

Modification instructions: Thank you for your valuable feedback. In response to your questions about our sampling method, we provide a detailed explanation here and have made corresponding revisions to the manuscript. In our study, each research area was carefully divided into 3 sampling zones, and the ancient tea trees are scattered and do not follow a unified cultivation pattern, so the size of the research area cannot be used as a theoretical basis for the representativeness of the samples. Despite the significant differences in the size of the sampling areas, we determined 9 sampling points in each sampling zone using a grid method based on the distribution of tea trees. Each sampling point was selected in the area where tea trees were most densely grown, with an area of 50 meters by 50 meters. Within each sampling point, these points were sampled following an "S" shaped route to ensure that the soil samples collected from each area were representative. Through this method, we collected a total of 27 samples from each research area.We employed this systematic sampling approach to ensure even distribution and coverage of samples, thereby accurately reflecting the soil characteristics and tea quality of different regions. This method not only improved the efficiency of sample collection but also enhanced the reliability and validity of our research findings. Thank you for your suggestions, and we hope this information meets your requirements.

Author Response File: Author Response.pdf