Insights into Opposite and Positive Effects of Biochar and Organic Fertilizer on Red Soil Properties and Growth of Pennisetum giganteum

Round 1

Reviewer 1 Report

Please find the attachment.

Comments for author File: Comments.pdf

Author Response

Dear Reviewer,

Thank you for your valuable feedback and suggestions on our manuscript titled "Insights into opposite effects of Biochar and Organic Fertilizer on Red Soil Properties and Growth of Pennisetum Giganteum." We appreciate your thorough evaluation and acknowledge the areas that require improvement. We have carefully considered your comments and have addressed each of your queries below:

1. State the reason for selecting biochar and organic fertilizer. Kindly state its mechanism/reaction/kinetics with feedstock. Apart from that, such studies were done before many years. What is the novelty of this work? Please mention it in the manuscript properly.

Response: Thank you for your comments and suggestions. We appreciate your interest in understanding the reasons for selecting biochar and organic fertilizer in our study, as well as the novelty of our work. We have provided the necessary information in the revised manuscript (line 44-82). Thank you for bringing these points to our attention, and we appreciate your guidance in improving the manuscript.

2. Uncertainty analysis for a few graphs is very high. Based on that, it is impossible to derive any conclusion.

Response: Thank you for your valuable feedback. We appreciate your attention to the uncertainty analysis of the graphs presented in our manuscript. We have carefully re-evaluated all the data and made the necessary modifications to address this concern (Figure 1D).

3. repeatability statement is missing. This means how often experiments or analyses were repeated to derive a conclusion.

Response: Thank you for your feedback regarding the repeatability statement in our manuscript. We apologize for any confusion caused by the absence of this statement. We want to clarify that repeatability was an integral part of our experimental design and data collection process. In the Materials and Methods section of the revised manuscript, we have provided detailed information on how the experiments and analyses were repeated to ensure reliability and validity of the results. This includes information on the number of replicates, experimental setup, and data collection procedures. Furthermore, we have supplemented this information in the relevant tables and figures, where appropriate, to provide transparency and facilitate the understanding of the repeatability of our study. This includes presenting the number of replicates for each treatment and clearly indicating the statistical measures employed to assess the significance of the results.

4. Conclusion is always supported by data which is minimum in your manuscript.

Response: Thank you for your valuable feedback. We appreciate your suggestion regarding the conclusion of our manuscript. We have carefully considered your comment and have made revisions accordingly to ensure that our conclusion is well-supported by the data presented in the manuscript (line 458-474).

5. Literature review and research gap must be focused. (Especially the last two paragraphs of the

Introduction)

Response: Thank you for your feedback regarding the literature review and research gap in the Introduction section of our manuscript. We appreciate your suggestion to provide more focus in the last two paragraphs of the Introduction. In response to your comment, we have carefully revised the Introduction to address this concern (line 63-82). We have emphasized the specific research gap that our study aims to fill and have provided a more comprehensive review of the relevant literature to establish the context and significance of our work. Additionally, we have highlighted the novelty and contributions of our study in relation to previous research, thereby clarifying the unique aspects of our investigation. By making these revisions, we believe that the Introduction now provides a clearer and more focused overview of the research background, highlighting the gaps in existing knowledge and underscoring the importance of our study in addressing these gaps.

Reviewer 2 Report

The MS deals with an interesting aspect. However, some points need to be addressed.

 

The authors should highlight reason for selection of the test materials.

 

Methodology should have specific references. Representation of conclusion can be improved.

 

Figures should be more clear.

 

Pennisetum giganteum should be written in full when mentioned for the first  time, then abbreviated form should be used. Language should be checked thoroughly.

 Language should be checked thoroughly.

Author Response

Dear Reviewer,

Thank you for your valuable feedback on our manuscript. We appreciate your comments and suggestions. In response to your points, we have made the following revisions:

1. The authors should highlight reason for selection of the test materials.

Response: Thank you for your suggestion. We have carefully reviewed the Introduction section and have made revisions to highlight the reasons for selecting biochar and organic fertilizer as test materials in our study (line 44-82). In the revised Introduction, we provide a more detailed explanation of the rationale behind our choice of biochar and organic fertilizer. We emphasize their potential benefits in improving soil properties, enhancing nutrient availability, and promoting plant growth. We also discuss the relevance of these materials to the specific context of our study and the research gap that exists in understanding their effects on soil and crop productivity. By incorporating these additional details, we aim to better convey the significance of our choice of test materials and the innovative aspects of our research. We appreciate your feedback and believe that these revisions enhance the clarity and coherence of our manuscript.

2. Figures should be clearer.

Response: Thank you for your feedback regarding the clarity of the figures. We have carefully examined and made improvements to the figures based on your suggestion (Figure 2). The revised figures now have enhanced readability and visual clarity, ensuring that the data and key findings are presented more effectively.

3. Pennisetum giganteum should be written in full when mentioned for the first time, then abbreviated form should be used. Language should be checked thoroughly.

Response: Thank you for your feedback regarding the usage of the term "Pennisetum giganteum." We have carefully reviewed the manuscript and made the necessary changes to ensure consistency and clarity in its presentation (line 26, 32).

 

Reviewer 3 Report

 

1 、Authors should show the nutrient content of biochar and organic fertilizer， which are the important factors that influence the growth of Pennisetum Giganteum. Also should show the tested soil organic matter content.

2 、The drying time of plants(only one hour) is shorter which cannot achieve a constant dry weight of plants in line 127.

3、 Line 132 and L235 AV should be changed to AP？

4、2% BC group had 26.6% higher dry weight than the CK (Figure 1d). Why are the statistical results not significant？Please check the statistical results and explain meaning of letters in the table.

5 Why did the author only analyze soil microbial diversity of three treatments(Fig.3-4, Table3). Different biochar and Manure addition had different effects on soil microbial diversity. Therefore, authors needs to analyze the differences of microbial diversity among the five treatments, and requests the author to supplement the corresponding data for better analysis.

6、L416“Bacteroidota can serve as an indicator for measuring  soil quality”. The sentence should be change because soil quality is evaluated by many factors. One kind of soil bacterium relative proportion can’t measure soil quality.

7、The title of the article needs to be revised. Not only opposite effects of Biochar and Organic Fertilizer but also positive effects were discussed in this paper.

Author Response

Dear Reviewer,

Thank you for your valuable feedback on our manuscript. We appreciate your comments and suggestions. In response to your points, we have made the following revisions:

1. Authors should show the nutrient content of biochar and organic fertilizer， which are the important factors that influence the growth of Pennisetum Giganteum. Also should show the tested soil organic matter content.

Response: Thank you for your feedback. We have taken your suggestion into consideration and have added the nutrient content of biochar and organic fertilizer in the manuscript (line 92, 100, 102). We have also included information regarding the tested soil organic matter content. By providing these details, we aim to highlight the important factors that influence the growth of Pennisetum giganteum and ensure a more comprehensive understanding of the experimental conditions.

2. The drying time of plants(only one hour) is shorter which cannot achieve a constant dry weight of plants in line 127.

Response: Thank you for bringing this to our attention. We apologize for the inaccurate description of the drying time of plants. We have revisited the method and made the necessary revisions “the bags were oven-dried at 105 °C for one hour to kill the fresh-tissues and then dried at 65 °C until a constant weight reached” to ensure clarity and accuracy (line 119-120).

3. Line 132 and L235 AV should be changed to AP？

Response: We apologize for the oversight and any confusion caused. We have carefully reviewed the manuscript and have made the necessary corrections. Line 132 and Line 235 have been updated to reflect the appropriate abbreviation "AP" instead of "AV." Thank you for bringing this to our attention, and we appreciate your attention to detail. If you have any further suggestions or concerns, please don't hesitate to let us know. Thank you for your valuable feedback.

4. 2% BC group had 26.6% higher dry weight than the CK (Figure 1d). Why are the statistical results not significant？Please check the statistical results and explain meaning of letters in the table.

Response: We appreciate your thorough review of the data. After conducting a comprehensive analysis and reevaluating the statistical results, we have identified an error in the reporting of the statistical significance. We apologize for any confusion caused. Upon reanalysis, the difference between the 2% BC group and the CK group in terms of dry weight is indeed statistically significant (Figure 1D). The corrected statistical results are now reflected in the revised version of Figure 1d. We have also included an explanation of the letters in the table to provide a clear understanding of their meaning. Thank you for bringing this to our attention, and we apologize for any inconvenience caused by the previous oversight.

5. Why did the author only analyze soil microbial diversity of three treatments (Fig.3-4, Table3). Different biochar and Manure addition had different effects on soil microbial diversity. Therefore, authors need to analyze the differences of microbial diversity among the five treatments, and requests the author to supplement the corresponding data for better analysis.

Response: We sincerely apologize for the lack of data regarding the microbial diversity analysis for all five treatments in our study. We greatly appreciate the reviewer's insightful comment and value the importance of a comprehensive analysis of microbial diversity. Initially, we conducted an extensive literature review to gain insights into the effects of different addition amounts, and we found consistent patterns of changes across various studies [1,2]. Based on these findings and considering the scope of our research, we carefully selected the most essential and representative treatments, including a control group (CK), a 2% organic fertilizer treatment (2% OF), and a 2% biochar treatment (2% BC). Regrettably, due to unforeseen limitations in our research time, we were unable to determine the microbial diversity for all samples as requested. We acknowledge that a more thorough analysis encompassing all treatments would have provided a more comprehensive understanding of microbial diversity, and we apologize for not being able to fulfill this expectation in our study. Nevertheless, we believe that the available data from the analyzed samples can still offer valuable insights into the effects of different biochar and organic fertilizer additions on soil microbial communities. The conducted analyses allowed us to observe trends and draw initial conclusions regarding the impact of these treatments on microbial diversity, as presented in Figures 3 and 4 and Table 3. We genuinely appreciate the reviewer's suggestion and assure you that in future studies, we will incorporate a larger sample size and conduct a comprehensive analysis of microbial diversity for all treatments. By doing so, we aim to provide a more comprehensive perspective on the topic and address the valuable point raised by the reviewer.

1. Wang, M.; Yu, X.; Weng, X.; Zeng, X.; Li, M.; Sui, X.J.M. Meta-analysis of the effects of biochar application on the diversity of soil bacteria and fungi. 2023, 11, 641.
2. Premalatha, R.P.; Poorna Bindu, J.; Nivetha, E.; Malarvizhi, P.; Manorama, K.; Parameswari, E.; Davamani, V. A review on biochar’s effect on soil properties and crop growth. 2023, 11, doi:10.3389/fenrg.2023.1092637.
3. L416“Bacteroidota can serve as an indicator for measuring  soil quality”. The sentence should be change because soil quality is evaluated by many factors. One kind of soil bacterium relative proportion can’t measure soil quality.

Response: Thank you for your clarification. The revised sentence emphasizes that “The dominance of Bacteroidota differs significantly from the blank control, Bacteroidota community can be an important indicator of soil quality in studies of soil biological degradation processes” (line 410-412). We appreciate your feedback and have made the necessary changes to ensure clarity and accuracy in our manuscript.

7. The title of the article needs to be revised. Not only opposite effects of Biochar and Organic Fertilizer but also positive effects were discussed in this paper.

Response: We appreciate your feedback regarding the title of our article. After careful consideration, we have revised the title to accurately reflect the content of our study. The revised title is now "Insights into the Opposite and Positive Effects of Biochar and Organic Fertilizer on Red Soil Properties and Growth of Pennisetum Giganteum." (line 2-4). This revised title better captures the dual effects discussed in the paper, providing a more comprehensive overview of our findings.

 

Reviewer 4 Report

Comment for the author:

§  The concept of optimizing biochar potential for improving the growth and yield attributes good one.  However, the work needs a minor revision in its current state.

 Comment

§  L146-147: the mixture was 146 colored at 880 nm need for correction

§  Replace  P<0.05 to P≤ 0.05 in MS including figure and table

§  Check Fig 1D. The letter above the error bar is not seemed to be correct.

§  Fig 2. The error bar is not properly visible. Kindly replace it with high-resolution Fig.

§  The value present in parentheses in the table is not in the correct form. This should be added in the main value in  ± form. Moreover, in the table caption, it should be also mentioned whether it is a Standard error or standard deviation

§  Reference should be in J format. Moreover, the genera name should be in italics  

Author Response

Dear Reviewer,

Thank you for your valuable feedback on our manuscript. We appreciate your comments and suggestions. In response to your points, we have made the following revisions:

• L146-147: the mixture was 146 colored at 880 nm need for correction

Response: Thank you for pointing out the error in the wording. We sincerely apologize for the mistake. We have now corrected the sentence in line 146-147 to accurately state that the mixture was measured at 880 nm (line 139). We appreciate your attention to detail, and we strive to ensure accuracy and clarity in our manuscript.

• Replace P<0.05 to P≤0.05 in MS including figure and table

Response: We appreciate your attention to detail and the clarification regarding the use of statistical notation. After careful consideration and examination of the writing specifications of other articles, we have observed that the majority of the literature utilizes "P < 0.05" to denote statistical significance. This convention has been widely accepted in the scientific community to indicate a statistically significant level. Based on this information, we have decided to retain the notation "P < 0.05" in our manuscript, as it aligns with the prevailing practice in the field. We believe that maintaining consistency with established standards will ensure clarity and facilitate better understanding among readers and researchers.

• Check Fig 1D. The letter above the error bar is not seemed to be correct.

Response: Thank you for bringing this to our attention. We have thoroughly reviewed Figure 1D and have made the necessary corrections to ensure the accuracy of the letter above the error bar. We apologize for any confusion caused and appreciate your diligence in reviewing the figure.

 

• Fig 2. The error bar is not properly visible. Kindly replace it with high-resolution Fig.

Response: Thank you for your feedback. We have taken your suggestion into consideration and have replaced Figure 2 with a higher-resolution image to ensure better visibility of the error bars. We apologize for any inconvenience caused by the previous image quality and appreciate your attention to detail.

• The value present in parentheses in the table is not in the correct form. This should be added in the main value in ± form. Moreover, in the table caption, it should be also mentioned whether it is a Standard error or standard deviation.

Response: Thank you for bringing this to our attention. We have revised the values in the table to include them in the main value in the ± form, as you suggested (Table 1, Table 2, Table 3). Additionally, we have updated the table caption to specify whether the values represent the standard error or standard deviation. These changes will improve the clarity and accuracy of the table presentation.

• Reference should be in J format. Moreover, the genera name should be in italics.

Response: Thank you for your suggestion regarding the reference format. We have now revised the references to follow the J format as per your recommendation. Additionally, we have ensured that the genera names are displayed in italics, in accordance with the standard practice in scientific writing. These modifications will enhance the consistency and adherence to formatting conventions in our manuscript.

 

Reviewer 5 Report

Please check the file. 

Comments for author File: Comments.pdf

Author Response

Dear Reviewer,

Thank you for your valuable feedback on our manuscript. We appreciate your comments and suggestions. In response to your points, we have made the following revisions:

1. Line 102 – mentions available phosphorus as AP but in lines 28, 132, 134, 235, 236, 369, 384

indicated as AV.

Response: Thank you for bringing this to our attention. We have carefully reviewed the manuscript and made the necessary corrections. We apologize for any confusion caused by the inconsistent use of terminology. The term "available phosphorus" will now be consistently referred to as "AP" throughout the manuscript to maintain clarity and consistency.

2. Line 103 – suggested to spell nitrate nitrogen and ammonium nitrogen and then include the

chemical symbols.

Response: Thank you for your suggestion. We have revised the manuscript to spell out "nitrate nitrogen" and "ammonium nitrogen" and include their chemical symbols (NO₃^--N and NH₄⁺-N) for clarity and precision (line 93-94).

3. Line 111- do you have pH values for OF and BC?

Response: Thank you for your comment. We apologize for the oversight in not including the pH values for biochar (BC) and organic fertilizer (OF) in the manuscript. We have now added the pH values of BC and OF to provide a more comprehensive understanding of the material characteristics in our study (line 100,103).

3. Line 178 – Why nine samples instead of fifteen? Which nine samples?

Response: Thank you for bringing up this question. We apologize for any confusion caused by the mention of nine samples instead of fifteen. In our study, we focused on analyzing the microbial diversity in specific treatments that we considered to be the most important and representative. Therefore, we selected nine samples, including three replicates each of the control (CK), 2% biochar (BC), and 4% biochar (BC) treatments, for microbial diversity analysis (line 162-163). We did not conduct microbial diversity analysis for the remaining six samples. This approach allowed us to obtain valuable insights into the effects of these specific treatments on microbial diversity. We have clarified this in the Materials and Methods section to provide a clear explanation of our sampling strategy.

3. Lines 194, 223, 229, 232, 239, 253, 263, 348, 349 – check formatting for ‘p’.

Response: Thank you for bringing this to our attention. We have carefully reviewed the manuscript and made the necessary formatting changes for the 'p' values. We have now used the appropriate notation, including the 'p' symbol followed by the corresponding value. This formatting ensures consistency and clarity in presenting the statistical significance of our findings. Thank you for your diligence in reviewing our manuscript.

4. Line 238 – OF significantly increased CaCl2 – P content only at 4%. The line suggests both at 2%

and 4%. Also, in line 241 – only Ca-P shows significant difference in table 1. This paragraph needs

to be rewritten.

Response: Thank you for bringing these concerns to our attention. We apologize for any confusion caused by the previous wording and appreciate your feedback in helping us improve the clarity and accuracy of our manuscript. Based on your feedback and our careful review of the data and relevant articles, we have made the necessary revisions to address the issues in the paragraph. It is worth noting that the differences between the Al-P and Fe-P fractions were not statistically significant in the results of the phosphorus fractionation analysis. We apologize for any confusion caused by the previous wording and appreciate your attention to detail in pointing out these issues. The revised paragraph now accurately reflects the findings: “Regarding soil CaCl₂-P, the biochar group exhibited a minor inhibitory effect, whereas the organic fertilizer group significantly enhanced the soil CaCl₂-P content (P<0.05). Specifically, the application of 2% OF led to an 86.5% increase, while 4% OF resulted in a substantial 255.3% increase. In the Phosphorus fractionation system, there was no significant difference in soil Al-P and Fe-P, but Ca-P showed a significant change, with 2% BC, 4% BC, 2% OF, and 4% OF increasing Ca-P content by 14.7%, 1.9%, 11.9%, and 90.6%, respectively (P<0.05). Among them, 4% OF was distinctly better than the other treatments.” (line 230-237)

5. Line 262 – check for spacing ‘2% OF’.

Response: Thank you for bringing this to our attention. We apologize for the spacing issue (line 255). We will make the necessary correction and ensure that it is written as "2% OF" with proper spacing.

6. Line 281 – Why three treatments instead of five? Which three?

Response: We apologize for the oversight in not including this information initially. We have now provided a detailed explanation of the selected treatments, which include the control group (CK), the 2% organic fertilizer treatment (2% OF), and the 2% biochar treatment (2% BC) (line 162-163). These treatments were chosen as they represent key factors in the study and allow for a comprehensive analysis of microbial diversity. We appreciate your understanding and have made the necessary updates to the manuscript.

7. Line 330 – check formatting for ‘dry’.

Response: Thank you for pointing out the formatting error. We apologize for the mistake, and we have now corrected the formatting of the word "dry" accordingly (line 323).

8. Table 3 – lists two treatments as 2% BC and 2% OF – this should be clearly mentioned in the

methods section.

Response: Thank you for your feedback regarding Table 3. We apologize for the oversight in not clearly mentioning the treatments of 2% BC and 2% OF in the methods section. We have now supplemented this information in the materials and methods to provide clarity on the treatments included in the analysis of microbial diversity (line 162-163).

9. The reference list is too long and some citations are older than 2010.

Response: Thank you for your feedback regarding the reference list. We understand your concern about the length and the inclusion of older citations. However, it is important to note that the literature we have cited is relevant and necessary for the study. These references provide valuable background information, support our methodology, and contribute to the overall scientific context of the research. While we have included some older references, they are seminal works that have made significant contributions to the field. We believe that the inclusion of these references enhances the credibility and comprehensiveness of our study.

 

Round 2

Reviewer 1 Report

The revised manuscript is fine.

Author Response

I wanted to express my sincere appreciation for taking the time to review the revised version of my manuscript. I am pleased to hear that the revisions I made to the manuscript have been found satisfactory. Your valuable insights and suggestions have significantly contributed to refining the clarity, coherence, and overall quality of the manuscript.

Reviewer 3 Report

The manuscript is the one I once reviewed in previous version. It has been greatly improved. What I concern about in previous version has been addressed the mostly in the revised version. Yet further revisions are needed.

I suggested to delete fresh weigh (Fig1.C) because the fresh weight can’t explain the difference of biomass between treatments.

The manuscript is the one I once reviewed in previous version. It has been greatly improved. What I concern about in previous version has been addressed the mostly in the revised version. Yet further revisions are needed.

I suggested to delete fresh weigh (Fig1.C) because the fresh weight can’t explain the difference of biomass between treatments.

 

Author Response

I appreciate your suggestion regarding the deletion of the fresh weight data from Figure 1C. I fully understand your point that fresh weight may not effectively explain the differences in biomass between treatments. Fresh weight and dry weight have similar trends, but there are still some gaps. Compared with fresh weight, it is undeniable that the biomass represented by dry weight is more significant. After careful consideration, I combine the two sets of data (Figure 1). In addition, the corresponding changes have been made in the article and highlighted in red.