PONE-D-19-33392

The response of soil Olsen-P to the P budgets of three typical cropland soil types under long-term fertilization

PLOS ONE

Dear Mrs Zhang,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

We would appreciate receiving your revised manuscript by Feb 16 2020 11:59PM. When you are ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter.

To enhance the reproducibility of your results, we recommend that if applicable you deposit your laboratory protocols in protocols.io, where a protocol can be assigned its own identifier (DOI) such that it can be cited independently in the future. For instructions see: http://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols

Please include the following items when submitting your revised manuscript:

• A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). This letter should be uploaded as separate file and labeled 'Response to Reviewers'.
• A marked-up copy of your manuscript that highlights changes made to the original version. This file should be uploaded as separate file and labeled 'Revised Manuscript with Track Changes'.
• An unmarked version of your revised paper without tracked changes. This file should be uploaded as separate file and labeled 'Manuscript'.

Please note while forming your response, if your article is accepted, you may have the opportunity to make the peer review history publicly available. The record will include editor decision letters (with reviews) and your responses to reviewer comments. If eligible, we will contact you to opt in or out.

We look forward to receiving your revised manuscript.

Kind regards,

Vassilis G. Aschonitis

Academic Editor

PLOS ONE

Journal Requirements:

1. When submitting your revision, we need you to address these additional requirements.

Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming. The PLOS ONE style templates can be found at

http://www.journals.plos.org/plosone/s/file?id=wjVg/PLOSOne_formatting_sample_main_body.pdf and http://www.journals.plos.org/plosone/s/file?id=ba62/PLOSOne_formatting_sample_title_authors_affiliations.pdf

2.  Please include captions for your Supporting Information files at the end of your manuscript, and update any in-text citations to match accordingly. Please see our Supporting Information guidelines for more information: http://journals.plos.org/plosone/s/supporting-information.

3. Please include your tables as part of your main manuscript and remove the individual files. Please note that supplementary tables (should remain/ be uploaded) as separate "supporting information" files.

4. We suggest you thoroughly copyedit your manuscript for language usage, spelling, and grammar. If you do not know anyone who can help you do this, you may wish to consider employing a professional scientific editing service.  

Whilst you may use any professional scientific editing service of your choice, PLOS has partnered with both American Journal Experts (AJE) and Editage to provide discounted services to PLOS authors. Both organizations have experience helping authors meet PLOS guidelines and can provide language editing, translation, manuscript formatting, and figure formatting to ensure your manuscript meets our submission guidelines. To take advantage of our partnership with AJE, visit the AJE website (http://learn.aje.com/plos/) for a 15% discount off AJE services. To take advantage of our partnership with Editage, visit the Editage website (www.editage.com) and enter referral code PLOSEDIT for a 15% discount off Editage services.  If the PLOS editorial team finds any language issues in text that either AJE or Editage has edited, the service provider will re-edit the text for free.

Upon resubmission, please provide the following:

• The name of the colleague or the details of the professional service that edited your manuscript
• A copy of your manuscript showing your changes by either highlighting them or using track changes (uploaded as a *supporting information* file)
• A clean copy of the edited manuscript (uploaded as the new *manuscript* file)

5. Please include your tables as part of your main manuscript and remove the individual files. Please note that supplementary tables (should remain/ be uploaded) as separate "supporting information" files.

6. Please ensure that you refer to Figure 9 in your text as, if accepted, production will need this reference to link the reader to the figure.

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Partly

Reviewer #2: Yes

**********

2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: No

Reviewer #2: Yes

**********

3. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

**********

4. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: No

Reviewer #2: Yes

**********

5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: It is an interesting article, which I strongly recommend to be revised and submitted again, as it includes data for many years from crop yield, phosphorus fertilization and phosphorus budget. However, there are some comments I would like to make: The statistical analysis has not been performed appropriately. I would recommend that the authors conduct a Repeated measures ANOVA with three factors for Maize: Soil type (Eutric Cambisol, Calcaric Cambisol and Luvic Phaesoms), P budget and time (year as time factor) to claim the effect of long-term (time) phosphorus fertilization (phosphorus budget) over different soil types (Soil type). You can then present the results in different graphs (as you have already presented them) but put the error bars that result from the Repeated measures analysis. In the text you must explain if there are any interactions and provide the p value of the analysis. You will then conduct the same analysis for wheat only for Qiyang and Zhengzhou regions.

There are also some comments below showing some examples of revisions that have to be made both for statistics and English (the language is not very clear at some points):

Line 106: “In order to analyses in spatial variation” should be written as follows:

In order to analyze the spatial variation …

Line 117: “Soil samples from the arable layer (0–20 cm) were collected randomly from each site” should be written as follows:

The initial soil samples, before treatment application, were collected randomly from the arable layer (0-20 cm) from each site in 1990.

Line 164: Conduct a Repeated measures ANOVA (with year as time factor) in order to claim P budget was lower in Luvic Phaeozems compared to Eutric Cambisol. LSD and t-student test are not enough when you have repeated measures.

Line 259: Conduct a Repeated measures ANOVA with three factors for Maize: Soil type (Eutric Cambisol, Calcaric Cambisol and Luvic Phaesoms), P budget and time (year as time factor) to claim the effect of long-term (time) phosphorus fertilization (phosphorus budget) over different soil types (Soil type). You can then present the results in different graphs (as you have already presented them) but put the error bars that result from the Repeated measures analysis. In the text you must explain if there are any interactions and provide the p value of the analysis. You will then conduct the same analysis for wheat only for Qiyang and Zhengzhou regions.

Line 266: Rephrasing: “The variation of crop yield was affected by soil pH obviously in Eutric…” should be written as follows: Soil pH decreased to 4.0-4.5 after 10 cropping years under CK and NK, and this caused yield reduction of (provide percentage and p value) compared to NPK, NPKS and NPKM treatments.

Line 268: Rephrasing: “Soil acidification was so serious to cause a decrease of crop production, even no…” should be written as follows:

Soil acidification was so serious that caused a decrease of crop production, and almost eliminated yield from 2006 to 2012 under NK.

Line 247: Compare to instead of "Compared with"

Line 276: When the amount of P fertilizers was higher than crop uptake instead of "was higher the crop uptake".

Line 286: Thus, taking advantage instead of "Thus, taking advantaging"

Figure 2: I would recommend replacing the title of the graphs with Eutric Cambisol, Calcaric Cambisol and Luvic Phaesoms instead of Qiyang, Zhengzhou and Gongzhuling.

Figure 2: You need to provide error bars for the various treatments for each of the experimental years. You also need to conduct a repeated measures ANOVA (with year as the time factor) in order to claim the difference between the treatments.

Figure 6 and Figure 8: ** represents P<0.01. You need to remove this, because there are not error bars on the graph.

Reviewer #2: Comments:

The key finding of this manuscript is the response of soil Olsen-P to the P budgets of three typical cropland soil types under long-term fertilization. Research reported in this manuscript fits well with the general scope of the journal. The results from three relatively long period of experiments seems valuable for understanding the mechanism of the variation of soil Olsen-P affected by different fertilization practices. However, only the P in the 0-20 cm soil is considered in the P budget in this research. The reason should be provided in the revised manuscript. Besides, there are several mistakes in the current version of the manuscript. Hence, I truly believe that a major revision is needed before the manuscript is reconsidered for the publication in this journal.

Specific comments:

L28: ‘g kg-1’? Please check.

L35: ‘g kg-1’? Please check.

L36: why were only two types of soils compared?

L40: the soil Olsen-P increased by 3.24-7.24 mg kg-1. However, the value of ‘7.24’ was not found in the following sentence.

L100: the sentence is incomplete. Please rewrite it.

L138: what is the applied soil P?

L139: the P from the fertilizer was not calculated in the formula?

L145: Not all the experiments have three replications (L105).

L151 Why and how was the data were normalized? It is not clear.

L186: replace ‘mean value of the three treatments’ as ‘average value over the three treatments’

L267:replace ‘，’ as ‘,’

L267: Is the soil acidification correlated to the fertilizer application practices? What is the reason for the serious soil acidification?

L277: the sentence ‘When the amount of P fertilizers was higher the crop uptake…’ is misleading. Please rewrite it.

L278: 71 kg of phosphorus fertilizer? Or the P2O5. Please recheck. The number seems too low.

L394-408: the conclusion is too similar to the result of the experiments. It's hard to see the academic value of research in the current version. Please rewrite it.

**********

6. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: Yes: Miltiadis Iatrou

Reviewer #2: No

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files to be viewed.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email us at figures@plos.org. Please note that Supporting Information files do not need this step.

The response of soil Olsen-P to the P budgets of three typical cropland soil types under long-term fertilization

PONE-D-19-33392R1

Dear Dr. Zhang,

We are pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it complies with all outstanding technical requirements.

Within one week, you will receive an e-mail containing information on the amendments required prior to publication. When all required modifications have been addressed, you will receive a formal acceptance letter and your manuscript will proceed to our production department and be scheduled for publication.

Shortly after the formal acceptance letter is sent, an invoice for payment will follow. To ensure an efficient production and billing process, please log into Editorial Manager at https://www.editorialmanager.com/pone/, click the "Update My Information" link at the top of the page, and update your user information. If you have any billing related questions, please contact our Author Billing department directly at authorbilling@plos.org.

If your institution or institutions have a press office, please notify them about your upcoming paper to enable them to help maximize its impact. If they will be preparing press materials for this manuscript, you must inform our press team as soon as possible and no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org.

With kind regards,

Vassilis G. Aschonitis

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #1: All comments have been addressed

Reviewer #2: All comments have been addressed

**********

2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Yes

**********

3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: Yes

**********

4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: Yes

**********

6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: I have seen that they have included the changes that I suggested and I think this publication is now ready to be submitted. I am particularly content that they reviewed their statistical analysis and incorporated changes in their text and the graphs. I can also see that they have improved a lot their English and the document looks now appropriate for publication. Anyway, this publication describes an experiment which has run for long time and clarifies some issues about phosphorus absorption and budget in soil.

Reviewer #2: (No Response)

**********

7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: Yes: Miltiadis Iatrou

Reviewer #2: Yes: Zhen Wang