Single-Time Mechanical Deep Placement Fertilization Using Bulk Blending Fertilizer on Machine-Transplanted Rice: Balanced Yield, Nitrogen Utilization Efficiency, and Economic Benefits

Response to Reviewer 1 Comments

1. Summary

Thank you very much for taking the time to review this manuscript. Please find the detailed responses below and the corresponding revisions/corrections highlighted/in track changes in the re-submitted files.

2. Questions for General Evaluation

Reviewer’s Evaluation

Response and Revisions

Does the introduction provide sufficient background and include all relevant references?

Yes

Are all the cited references relevant to the research?

Yes

Is the research design appropriate?

Yes

Are the methods adequately described?

Can be improved

Are the results clearly presented?

Yes

Are the conclusions supported by the results?

Yes

3. Point-by-point response to Comments and Suggestions for Authors

Comments 1: Line 1 Please make the title more concise and simple, too long.

Response 1: Thank you for pointing this out. We agree with this comment. Therefore, we have changed the title to make it more concise but retained the original point.

Comments 2: Line 94 Repetition of titles

Response 2: Agree. We have removed duplicate titles.

Comments 3: Line102 Normally, we do not specify soil classification as top soil, but the whole pedon

Response 3: Thank you for your comments. According to your comments, we have revised the description of the soil on line 107.

Comments 4: Line 111 Please specify the dose of each fertilizer (treatment)

Response 4: Thank you for your comments. And we described the dose of each treatment in Line 129-130, each treatment (except for N0) was applied at a rate of 216 kg N ha^-1 in this study (~30% less than the conventional N dose of local farmers).

Comments 5: Line 118 Please specify the depth of the fertilizer application

Response 5: Thank you for your comments. We added a description of the depth of fertilizer application on line 125.

Comments 6: Line124 Please state the application method for P and K fertilizers

Response 6: Thank you for your comments. We added a description of the application method for P and K fertilizers on line 132-133. All the P and K fertilizers in all treatments were broadcast by hand as basal fertilizers at one day before transplanting.

Comments 7: Line 134 Please explain in more detail

Response 7: Thank you for your comments. We think, in this experiment, except for fertilizer application, all other field management of the experiment remained consistent with the local high-yield production management protocols, so it had no effect on the experiment and does not need to be described in further detail.

Comments 8: Line 390 Please explain in more detail, how the SCU DPF provides better yield and NUE compared to other treatment, related to N dynamic in soil, such adsorption, immobilization and leaching.

Response 8: Thank you for your comments. According to your comments, We've added more descriptions of this at line 413-424.

4. Response to Comments on the Quality of English Language

Point 1: none

5. Additional clarifications

Sincerely thank you for your valuable suggestions, we have revised the entire article in detail based on your suggestions and have corrected some formatting errors in the article.

Response to Reviewer 2 Comments

1. Summary

Thank you very much for taking the time to review this manuscript. Please find the detailed responses below and the corresponding revisions/corrections highlighted/in track changes in the re-submitted files.

2. Questions for General Evaluation

Reviewer’s Evaluation

Response and Revisions

Does the introduction provide sufficient background and include all relevant references?

Yes

Are all the cited references relevant to the research?

Can be improved

Is the research design appropriate?

Yes

Are the methods adequately described?

Must be improved

Are the results clearly presented?

Can be improved

Are the conclusions supported by the results?

Can be improved

3. Point-by-point response to Comments and Suggestions for Authors

Comments 1: Write before the title that it is an Article.

Response 1: Thank you for pointing this out. We have added this before the title.

Comments 2: Add the Latin name of oats in the keywords.

Response 2: Agree. We have added the Latin name of oats in the keywords.

Comments 3: Abbreviations should be moved to the end of the publication, before the bibliography.

Response 3: Thank you for your comments. We found that the abbreviations have been described in detail in the abstract, so we have removed this content.

Comments 4: Briefly describe figure 1 and change the description of figure 1.

Response 4: Thank you for your comments. We have described Fig. 1 and change the description of Fig. 1 at line 102-106.

Comments 5: Name the laboratory where the soil samples were taken.

Response 5: Thank you for your comments. All soil base fertility was measured by ourselves, following Bao’s method (Line107-111).

Comments 6: In the text, enter only the reference number in brackets []

Response 6: Thank you for your comments. We have made the changes required by the journal.

Comments 7: Write the missing information in the Material and Methods chapter (details in pdf)

Response 7: Thank you for your comments. We have changed or described more details in the Materials and methods according to your comments. The fore crop was winter wheat (line 96-98) and the measurements of the yield and yield components have added at line 188-191.

Comments 8: Write the years from which the prices and costs were for economic calculations

Response 8: Thank you for your comments. The year of this costs was 2015. Because in 2015, we purchased all the farm supplies needed for the two-year experiment.

Comments 9: Describe the yielding of rice in more detail. What were the differences, e.g. percentage

Response 9: Thank you for your comments. We think that for this data we have described in detail below.

Comments 10: Check figure number 7

Response 10: Thank you for your comments. This was a mistake that we have fixed.

Comments 11: In conclusions, write what the differences were over the years

Response 11: Thank you for your comments. We think we have briefly described the conclusions of the study in this paper.

Comments 12: Revise the bibliography as required by the journal

Response 12: Thank you for your comments. We have made the changes required by the journal.

Comments 13: Write Latin names of species in italics

Response 13: Thank you for your comments. We have written Latin names of species in italics.

4. Response to Comments on the Quality of English Language

Point 1: none

5. Additional clarifications

Sincerely thank you for your valuable suggestions, we have revised the entire article in detail based on your suggestions and have corrected some formatting errors in the article.

Response to Reviewer 3 Comments

1. Summary

Thank you very much for taking the time to review this manuscript. Please find the detailed responses below and the corresponding revisions/corrections highlighted/in track changes in the re-submitted files.

2. Questions for General Evaluation

Reviewer’s Evaluation

Response and Revisions

Does the introduction provide sufficient background and include all relevant references?

Can be improved

Are all the cited references relevant to the research?

Must be improved

Is the research design appropriate?

Must be improved

Are the methods adequately described?

Can be improved

Are the results clearly presented?

Must be improved

Are the conclusions supported by the results?

Yes

3. Point-by-point response to Comments and Suggestions for Authors

Comments 1: The title is good however, very lengthy. The authors are requested to shorten the title without losing its actual message and scientific flavour.

Response 1: Thank you for pointing this out. We have shorten the title without losing its actual message and scientific flavour.

Comments 2: I suggest a thorough revision starting from the write-up. I find it acceptable to a high extent, in both the English language and the use of sentences.

Response 2: Agree. We've checked the English language and made some changes based on the comments.

Comments 3: I highly recommend authors review the whole manuscript carefully so that your manuscript is consistent with the use of abbreviations, spacing, many typographical errors, etc.

Response 3: Thank you for your comments. We have revised the formatting of the manuscript to comply with journal requirements.

Comments 4: I advise the authors to use keywords that do not exist in the manuscript title for wider dissemination of the article in the search engines.

Response 4: Thank you for your comments. We have changed the keywords to make them more appropriate.

Comments 5: I suggest deleting these abbreviations since the author mentioned their full expansions within the abstract section or vice versa by meaning deleting them from the abstract section and keeping them here.

Response 5: Agree. We've deleted it.

Comments 6: Describe in brief the scientific methods with their references used to determine the experimental soil properties. Also, present each parameter in mean value ± standard error.

Response 6: Thank you for your comments. According to your comments, we have changed the manuscript and presented each parameter in mean value ± standard error in Line 107-111.

Comments 7: Please, What is it referring to the T letter on the left vertical line? each figure or table must be stand alone.

Response 7: Thank you for your comments. It was a mistake and we have changed the mistake in Fig. 1.

Comments 8: What are the coating materials chemically?

Response 8: The coating materials were describe in Line 116-119. PCUs were coated by polymer and SCU was coated by sulfur.

Comments 9: This Ref is not found in the Ref list and its citation writing method is inconsistence with the journal style.

Response 9: Agree. It was a mistake and we have changed.

Comments 10: Describe this measurement method with some details with a recent Refs.

Response 10: Thank you for your comments. We have described this measurement method in Line 170-173.

Comments 11: To be more clearer Figure, please show these abbreviation within the Figure or vice versa and give it, for example a subtitle "a" and ditto for DPF technique.

Response 11: Thank you for your comments. We have changed according to your comments.

Comments 12: Why this procedure?

Response 12: All the plant samples were oven-dried at 105°C for 30 min. This step is designed to inactivate enzymes in the plant for a short period of time to prevent changes in indicators such as nitrogen content.

Comments 13: Please, write these yield components and their measuring methods and units.

Response 13: Thank you for your comments. The measurements of the yield and yield components have added at line 188-191.

Comments 14: A field experiment of such nature needs to be tested with a more suitable statistical technique rather than a one-way analysis of variance that supposes homogeneity of all experimental plots, which is very difficult, if not impossible in the open experimental field. I would suggest a two-way analysis of variance or a factorial experiment with two factors to be used for such an experiment.

Response 15: Thank you for your comments. We have reorganized the description of this section in Line 225-229.

Comments 15: Please, add the standard error value for each mean in this table and all tables or figures throughout the manuscript.

Response 15: Thank you for your comments. We have added the standard error value in all tables.

Comments 16: Table 2 This percent per???

Response 16: In Table 2, filled grain rate means the proportion of full grains to total number of grains and the filled grain weight means the weight of single grain.

Comments 17: Please show these abbreviations as table footnotes. Remember always that the Table or Figure must be stand-alone.

Response 17: Thank you for your comments. We have changed all the Tables and Figures.

Comments 18: Line 345 Subscripted this（S0）.

Response 18：Thank you for your comments. We have described this in Line 369-370.

Comments 19: I think this sentence more suitable for the Introduction section.

Response 19：Agree. We have changed this.

4. Response to Comments on the Quality of English Language

Point 1: This study investigated by He et al. targets an interesting topic and provides important fertilization techniques in further understanding nitrogen use efficiency, and reducing labor costs. I have read this manuscript very carefully, it is presented in a good manner with some typographical errors and the text needs a bit of editing. The manuscript's concept is very well; however, the discussion should be scientifically deeper. In view of the above, I consider that the work requires MAJOR REVISION to proceed with its publication in the journal. Please see the attached PDF revised manuscript.

Response 1: Sincerely thank you for your suggestion, we have revised the formatting and English presentation of the full manuscript according to your comments and labeled it in the newly uploaded manuscript.

5. Additional clarifications

Sincerely thank you for your valuable suggestions, we have revised the entire article in detail based on your suggestions and have corrected some formatting errors in the article.

Response to Reviewer 4 Comments

1. Summary

Thank you very much for taking the time to review this manuscript. Please find the detailed responses below and the corresponding revisions/corrections highlighted/in track changes in the re-submitted files.

2. Questions for General Evaluation

Reviewer’s Evaluation

Response and Revisions

Does the introduction provide sufficient background and include all relevant references?

Can be improved

Are all the cited references relevant to the research?

Can be improved

Is the research design appropriate?

Yes

Are the methods adequately described?

Yes

Are the results clearly presented?

Can be improved

Are the conclusions supported by the results?

Can be improved

3. Point-by-point response to Comments and Suggestions for Authors

Comments 1: Title: I suggest making it shorter. maximum of 12 words.

Response 1: Thank you for pointing this out. We have shorten the title without losing its actual message and scientific flavour.

Comments 2: Abstract: I suggest presenting the problem more clearly. Well, the issue of controlled release impacts the release of NH₄. So I suggest bringing this context better.

At the end, present a sentence concluding the work.

Response 2: Thank you for your comments. We've changed the abstract in the newly uploaded manuscript.

Comments 3: Abbreviations, I suggest removing, as they are all described throughout the text.

Response 3: Agree. We've deleted it.

Comments 4: Introduction, I suggest reviewing, as I believe that the issue of N and gas emissions should be better contextualized. Furthermore, bring context to rice production.

Response 4: Thank you for your comments. In this article we are not concerned with gas emissions, but more with the match between nitrogen release and rice nitrogen demand under the fertilizer incorporation fertilization method, and thus whether it can improve its nitrogen utilization, yield, and economic efficiency.

Comments 5: What years were the experiments carried out?

Response 5: The experiment was carried out in 2015 and 2016.

Comments 6: Check the formatting that the magazine requires.

Response 6: Thank you for your comments. We have made the changes required by the journal.

Comments 7: The amount used was collected in which month/year? Value on what basis?

Response 7: Thank you for your comments. The year of this costs was 2015. Because in 2015, we purchased all the farm supplies needed for the two-year experiment.

Comments 8: See reference line 138. outside the standards.

Response 8: Thank you for your comments. We have changed.

Comments 9: In the graphs I suggest standardizing, because in the climate graph (Fig 1) it is in these and the other figures are in days after transplanting. This makes it difficult, because in the second cycle I believe there was a lot of precipitation. Which can influence the release of N.

Response 9: Thank you for your comments. We have described Fig. 1 and change the description of Fig. 1 at line 102-106.

Comments 10: Describe this measurement method with some details with a recent Refs.

Response 10: Thank you for your comments. We have described this measurement method in Line 170-173.

4. Response to Comments on the Quality of English Language

Point 1: none

5. Additional clarifications

Sincerely thank you for your valuable suggestions, we have revised the entire article in detail based on your suggestions and have corrected some formatting errors in the article.

Response to Reviewer 5 Comments

1. Summary

Thank you very much for taking the time to review this manuscript. Please find the detailed responses below and the corresponding revisions/corrections highlighted/in track changes in the re-submitted files.

2. Questions for General Evaluation

Reviewer’s Evaluation

Response and Revisions

Does the introduction provide sufficient background and include all relevant references?

Yes

Are all the cited references relevant to the research?

Yes

Is the research design appropriate?

Yes

Are the methods adequately described?

Yes

Are the results clearly presented?

Can be improved

Are the conclusions supported by the results?

Can be improved

3. Point-by-point response to Comments and Suggestions for Authors

Comments 1: The title is long and should be shortened on the one hand, and on the other hand, the title cannot be the result of the study, but rather it must express a hypothesis.

Response 1: Thank you for pointing this out. We have shorten the title without losing its actual message and scientific flavour.

Comments 2: Shorten the abstract to approximately 200 words. It is important to shorten the introduction at the beginning of the abstract to only two lines.

Response 2: Thank you for pointing this out. We've changed the abstract and shorten the introduction at the beginning of the abstract to only two lines.

Comments 3: Line 128: Mention the source of the rice cultivar (Ningjing7) used in the experiment.

Response 3: Thank you for your comments. We have described the source of Ningjing7 in Line 136-137.

Comments 4: What is the growing medium that is placed in the trays? Mention where the trays were placed after the rice seeds were planted in them. Also mention the conditions in the place where the trays were placed (temperature, light, humidity, irrigation and care of the plants until the time of transport to the field).

Response 4: Thank you for your comments. According to your comments, we have described how to do seedlings in line 137-142.  The seeds were soaked with water for 2 days and the volume ratio of the solution to the seed was 3:1. After soaking, the seeds were kept in the dark at 30 ◦C for 1 day . Then the germinated seeds (120 g) were sown in the seedling tray (57.5 × 27.5 cm) containing organic substrates on 28 May 2015 and 31 May 2016.   The nursery management adopted for seedling cultivation employed the application of micro-irrigation for hard land seedling raising technique.

Comments 5: It seems that the seeds were planted on two dates (May 28 and May 31). Why was the planting done on two dates, 3 days apart?

Response 5: Because the weather varies from year to year, in 2016 it coincided with rainfall and low temperatures, so planting was delayed by three days. However, there was no effect on the number of green leaves of the seedlings at the time of transplanting, and all were transplanted at four green leaves.

Comments 6: Why were the seedlings of the first date (May 28) transferred and planted after 23 days, while the seedlings of the second date (May 31) after only 15 days?

Response 6: This was because we would make sure that the seedlings had a consistent number of green leaf books when transplanted, as the 2015 seedlings had cooler temperatures during the nursery period and therefore grew slower and required a longer nursery time. We would ensure that the seedlings have a green leaf number of 4 when they were finally transplanted.

Comments 7: Is everything written in lines 165-169 the title of Figure 2? If so, this title must be amended and shortened so that it does not include an explanation of the method and does not exceed two lines.

Response 7: Thank you for your comments. Unnecessary parts have been deleted.

Comments 8:  What is written on the axes in some figures (such as Figures: 4 and 5) is not clear and can hardly be seen, so a larger font size should be used.

Response 8: Thank you for your comments. We have revised Fig.4/5/6 to make them look clearer.

4. Response to Comments on the Quality of English Language

Point 1: Minor editing of English language required: Pay attention to some simple linguistic errors, such as: Line 187: Modify "were" to "was". Line 284: modified "compared" to "compared".

Response 1: Sincerely thank you for your suggestion, we have revised the English presentation of the full manuscript according to your comments and labeled it in the newly uploaded manuscript.

5. Additional clarifications

Sincerely thank you for your valuable suggestions, we have revised the entire article in detail based on your suggestions and have corrected some formatting errors in the article.

Response to Reviewer 3 Comments

1. Summary

Thank you very much for taking the time to review this manuscript. Please find the detailed responses below and the corresponding revisions/corrections highlighted/in track changes in the re-submitted files.

2. Point-by-point response to Comments and Suggestions for Authors

Comments 1: L107-111: Describe in brief the scientific methods with their references used to determine the experimental soil properties.

P and K fertilizers were applied as basal dressings at rates of 108 kg L130-132: P2O5 ha-1 and 172 kg K2O ha-1, respectively. All the P and K fertilizers in all treatments were broadcast by hand as basal fertilizers at one day before transplanting.

Response 1: Thank you for pointing this out. We have added a description of soil basal fertility measurements in Line107-112. And the dose of P and K fertilizers was determined based on the practical application of rice precision dosing cultivation technology in this area for many years. In this article, we focus more on N fertilizers, and based on the unique difference principle of the experiment, we kept the amount of P and K fertilizers the same.

Comments 2: "Actual field densities were established at 18 hills m-2 for 2015 and 24 hills m-2 for 2016 with 3-4 seedlings per hill" Apart from the two study factors, I think the difference in plant standing density will affect the final yield from one season to the other. Please, show that.

Response 2: Thank you for your comments. You have raised a critical issue and we have had a profound discussion about it. First of all, the data in the article were actual measurements of density taken by us at the maturity stage, and there were some deviations from the set values due to a certain degree of machine error in the transplanting of the rice blanket-seedling machine-transplanter. For this difference, we concluded that there was no significant impact on the results. As we focused our inquiry on fertilizer type and fertilizer application method, the data results were consistent with the two-year trend. So, we modified Fig.7 to remove the year-to-year effect on the data and focus more on fertilizer type and fertilization method.

Comments 3: "After sampling, fresh soil samples were immediately extracted with 2M KCl solution. Soil NH4+-N and NO3--N concentrations were measured by an auto-analyzer (Model AA3, Bran-Luebbe, Hamburg, Germany)". Describe this measurement method with some details with recent Refs.

Response 3: Thank you for your comments. This method is the auto-analyzer (Model AA3, Bran-Luebbe, Hamburg, Germany) method regarding the determination of two inorganic nitrogen, and in the article we have redescribed the principle of its determination in Line169-177.

Comments 4: "Tissue N contents" The measurement unit is missing.

Response 4: Thank you for your comments. We have refined the description of the method for the determination of N content in Line 205-207 and labeled the units of measurement of N content in the Table S2.

Comments 5: "Datasets of each year were examined separately by one-way 224 analysis of variance." A field experiment of such nature needs to be tested with a more suitable statistical technique rather than a one-way analysis of variance that supposes homogeneity of all experimental plots, which is very difficult, if not impossible in the open experimental field. I would suggest a two-way analysis of variance or a factorial experiment with two factors to be used for such an experiment.

Response 5: Thank you for your comments. We have fully considered your suggestions and discussed them. We believe that your suggestion is correct and have made changes to the method of analyzing the data in Line 228.

3. Response to Comments on the Quality of English Language

English language fine. No issues detected

4. Additional clarifications

Sincerely thank you for your valuable suggestions, we have revised the entire article in detail based on your suggestions and have corrected some formatting errors in the article.