The use of humanure for cereal production under conventional and regenerative farming models - findings from a three-year grassland-to-arable transition

Katie Allen; Effie Papargyropoulou; Ruth Wade; Barbara Evans

doi:10.1371/journal.pone.0335625

Peer Review History

Original SubmissionMay 28, 2025
24 Jul 2025 Decision Letter - Paulo Pagliari, Editor Dear Dr. Allen, 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. Please submit your revised manuscript by Sep 07 2025 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org . When you're 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. A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'. 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We look forward to receiving your revised manuscript. Kind regards, Paulo H. Pagliari Academic Editor PLOS ONE Journal Requirements: When submitting your revision, we need you to address these additional requirements. 1. 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 https://journals.plos.org/plosone/s/file?id=wjVg/PLOSOne_formatting_sample_main_body.pdf and https://journals.plos.org/plosone/s/file?id=ba62/PLOSOne_formatting_sample_title_authors_affiliations.pdf . 2. In your Methods section, please provide additional information regarding the permits you obtained for the work. Please ensure you have included the full name of the authority that approved the field site access and, if no permits were required, a brief statement explaining why. 3. In the online submission form, you indicated that [Data available upon request.]. 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Please review your reference list to ensure that it is complete and correct. If you have cited papers that have been retracted, please include the rationale for doing so in the manuscript text, or remove these references and replace them with relevant current references. Any changes to the reference list should be mentioned in the rebuttal letter that accompanies your revised manuscript. If you need to cite a retracted article, indicate the article’s retracted status in the References list and also include a citation and full reference for the retraction notice. Additional Editor Comments: Please see the reviewer's comments for how to improve the manuscript. [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? Reviewer #1: Yes ******** 2. Has the statistical analysis been performed appropriately and rigorously? -->?> Reviewer #1: Yes ****** 3. Have the authors made all data underlying the findings in their manuscript fully available??> The PLOS Data policy Reviewer #1: No ****** 4. Is the manuscript presented in an intelligible fashion and written in standard English??> Reviewer #1: Yes ****** Reviewer #1: See my comments embedded in the attached reviewed file. Here, for example, is my last comment: This is truly a ground-breaking study (pun intended). Hats off to the researchers! FYI, the Glastonbury music festival utilizes what are probably “dry toilets” (as opposed to compost toilets) where a LOT of toilet material is collected and presumably composted off-site. From what I can tell, these toilets are being well-managed and could be a great source of material for future research. I don’t see any major problems with your research, other than the minor issues I have mentioned in my comments. Better sources of humanure would likely make a major difference in outcomes. Get your hands on the Humanure Handbook 4th edition (2019), as well as the Compost Toilet Handbook (2021). They can be downloaded as PDFs online. I can provide free PDF copies to researchers. Just email me a request (joe@josephjenkins.com). Joe Jenkins ****** 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: Joseph Jenkins ******** [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.] 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 PLOS at figures@plos.org Attachments Attachment Submitted filename: PONE-D-25-29073_Edited_Jenkins.pdf https://doi.org/10.1371/journal.pone.0335625.r001
Revision 1
4 Sep 2025 Author Response Response to Reviewers 04/09/2025 Response to Academic Editor Thank you for your swift response. I have made the requested changes and reuploaded the tracked changes and clean versions of the manuscript: - I have included a statement which indicates additional permits were not required as the study was conducted on a university-owned research site. - I have uploaded all the raw field data as an additional file. - I have reformatted the manuscript headings and supporting information files to match the style guides. Reviewer 1 Comments and Responses: Abstract: This needs to be defined in some detail. The term is used throughout the paper, but it is not clear what it means. > The term first appears in line 83, and the next paragraph (Line 84) explains the need to include specificity when using these kinds of terms which have multiple different interpretations. > The section beginning at Line 120 provides more detail about those features which are commonly considered under the ‘regenerative’ umbrella, and explains those features which were included within this experiment. > A full list of these practices undertaken on the regenerative plots is given in the Methods section in Table 1. Line 12: "Humanure" is human excrement (primariy fecal material and urine) recycled for agricultural purposes. It is recommended that the "toilet material" be composted prior to agricultural use. There is no evidence presented here that the humanure was composted. Composting, by definition, requires the production of internal biological heat in the organic material being composted, as described in the Humanure Handbook 4th edition (2019). The 1st edition of the Humanure Handbook (1994) was used as a reference in this study. The use of the word "humanure" in the title to this paper is correct. The humanure used in this study consisted of the aged contents of "dry toilets.," which consisted of humanure, along with whatever other contents were deposited in the toilets. If the toilet contents had been composted, there should be data regarding the organic materials that were utilized (humanure and what else), plus time and temperature factors. "Sawdust" was added, but was it sawdust, wood shavings, or wood chips? Was urine separated from the toilet contents, as is often the case with dry toilets? Separation of urine and inclusion of large carbon chunks (wood chips), will drastically alter the nutrient composition of the organic mass. These are important factors, and this sort of information, if included, would improve this research paper. To rectify this, I would suggest changing the definition of humanure as stated from "composted human feces" to something like "human excrement recycled for agricultural purposes." I expect that you would find that correctly composted human toilet material, including the urine, when mixed with other organic discards in the composting process. (kitchen food, agricultural byproducts, and food/beverage industry discards), will provide better agricultural outcomes. Not that the outcomes were bad here, but just saying. > Thank you for this insightful comment; this nuance has been a tricky point throughout my research, especially when considering the differences communicating with agricultural experts, sanitation experts, and non-expert audiences. It is something I have discussed at great length in my thesis, and challenged the idea that humanure and composting are always synonymous, and suggest some alternative and nuanced definitions. But, that’s away from the present point. I accept your comment here, that for this instance in this paper the phrasing is indeed wrong. As such I have amended it to your suggested wording, and have increased the amount of detail given for each humanure batch used in the experiment. Line 192: What kind(s) of sawdust? From trees or lumber? Fresh sawdust or aged? Actual sawdust, or woodchips or wood shavings (see Humanure Handbook 4th edition (2019). Thank you for raising the need for more specificity here. I have updated this line to explain that the batches differed, and have also included more details about each batch in the Supporting Information 2 file. Since these materials were arriving to me second-hand, where information about the contents is unknown, this is now made more clear. Line 361: Typo. should be "do"? > Well spotted, thank you! Fixed. Line 379: typo > Well spotted, thank you! Fixed. Line 582: Are these words necessary? > A valid question. They were included in attempts to move away from yield being perceived as the only metric of success, as this paper also considers the impacts on improving soil health. The sentence has been reworded for clarity. Line 625: typo > Well spotted, thank you! Fixed. Line 629: typo > Well spotted, thank you! Fixed. Line 672: should be two words > Well spotted, thank you! Fixed. Line 854: This is truly a ground-breaking study (pun intended). Hats off to the researchers! FYI, the Glastonbury music festival utilizes what are probably “dry toilets” (as opposed to compost toilets) where a LOT of toilet material is collected and presumably composted off-site. From what I can tell, these toilets are being well-managed and could be a great source of material for future research. I don’t see any major problems with your research, other than the minor issues I have mentioned in my comments. Better sources of humanure would likely make a major difference in outcomes. Get your hands on the Humanure Handbook 4th edition (2019), as well as the Compost Toilet Handbook (2021). They can be downloaded as PDFs online. I can provide free PDF copies to researchers. Just email me a request (joe@josephjenkins.com). Joe Jenkins > Thank you for these kind words, and for taking the time to review my research. I really appreciate it! Attachments Attachment Submitted filename: Response to Reviewers.docx https://doi.org/10.1371/journal.pone.0335625.r002
29 Oct 2025 Decision Letter - Paulo Pagliari, Editor Dear Dr. Allen, 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. Please submit your revised manuscript by Dec 13 2025 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org . When you're 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. A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'. A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'. An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'. If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: https://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols . Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols . We look forward to receiving your revised manuscript. Kind regards, Paulo H. Pagliari Academic Editor PLOS ONE Journal Requirements: If the reviewer comments include a recommendation to cite specific previously published works, please review and evaluate these publications to determine whether they are relevant and should be cited. There is no requirement to cite these works unless the editor has indicated otherwise. Please review your reference list to ensure that it is complete and correct. If you have cited papers that have been retracted, please include the rationale for doing so in the manuscript text, or remove these references and replace them with relevant current references. Any changes to the reference list should be mentioned in the rebuttal letter that accompanies your revised manuscript. If you need to cite a retracted article, indicate the article’s retracted status in the References list and also include a citation and full reference for the retraction notice. Additional Editor Comments: Katie, please go ahead and make the changes we spoke about and please make sure you use work track changes so that I can see what was changed easily and upload the revised version. [Note: HTML markup is below. Please do not edit.] Reviewers' comments: Reviewer's Responses to Questions Comments to the Author Reviewer #1: (No Response) ******** 2. Is the manuscript technically sound, and do the data support the conclusions??> Reviewer #1: Yes ****** 3. Has the statistical analysis been performed appropriately and rigorously? -->?> Reviewer #1: N/A ****** 4. Have the authors made all data underlying the findings in their manuscript fully available??> The PLOS Data policy Reviewer #1: No ****** 5. Is the manuscript presented in an intelligible fashion and written in standard English??> Reviewer #1: Yes ****** Reviewer #1: I think I would have first blended all of the humanure batches together thoroughly, then used the mix for this research, as it could have eliminated some of the discrepancies in the results. In short, I think this paper will likely inspire more researchers to study this subject matter. There have been many great opportunities to do so, but nobody to do the research. We composted hundreds of tons of humanure with sugarcane bagasse and food scraps in Haiti, only to have the project abandoned due to security problems when it was time to use the finished compost agriculturally. In the end, local farmers came and took the compost and used it for agricultural purposes, but nobody documented anything (see, for example https://youtu.be/VY5K2Jn7Om0?si=38vI5QET-RcMgHFN). I should add that this situation is occurring on several continents where large-scale humanure composting is taking place with little or no follow-up agricultural research. See the Compost Toilet Handbook for more information.] Good job with this research! ****** 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: JOSEPH JENKINS ******** [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 ensure your figures meet our technical requirements, please review our figure guidelines: https://journals.plos.org/plosone/s/figures You may also use PLOS’s free figure tool, NAAS, to help you prepare publication quality figures: https://journals.plos.org/plosone/s/figures#loc-tools-for-figure-preparation. NAAS will assess whether your figures meet our technical requirements by comparing each figure against our figure specifications. https://doi.org/10.1371/journal.pone.0335625.r003
Revision 2
19 Dec 2025 Author Response These comments to reviewers were addressed in the previous resubmission. This latest resubmission includes some additional information and changes which were suggested as a result of my PhD viva corrections. Attachments Attachment Submitted filename: Response_to_Reviewers_auresp_2.docx https://doi.org/10.1371/journal.pone.0335625.r004
8 Jan 2026 Decision Letter - Paulo Pagliari, Editor The use of humanure for cereal production under conventional and regenerative farming models - findings from a three-year grassland-to-arable transition PONE-D-25-29073R2 Dear Dr. Allen, We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements. Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication. An invoice will be generated when your article is formally accepted. Please note, if your institution has a publishing partnership with PLOS and your article meets the relevant criteria, all or part of your publication costs will be covered. Please make sure your user information is up-to-date by logging into Editorial Manager at Editorial Manager® and clicking the ‘Update My Information' link at the top of the page. For questions related to billing, please contact billing support . If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- 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. Kind regards, Paulo H. Pagliari Academic Editor PLOS One Additional Editor Comments (optional): Reviewers' comments: https://doi.org/10.1371/journal.pone.0335625.r005
Formally Accepted
Acceptance Letter - Paulo Pagliari, Editor PONE-D-25-29073R2 PLOS One Dear Dr. Allen, I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS One. Congratulations! Your manuscript is now being handed over to our production team. At this stage, our production department will prepare your paper for publication. This includes ensuring the following: * All references, tables, and figures are properly cited * All relevant supporting information is included in the manuscript submission, * There are no issues that prevent the paper from being properly typeset You will receive further instructions from the production team, including instructions on how to review your proof when it is ready. Please keep in mind that we are working through a large volume of accepted articles, so please give us a few days to review your paper and let you know the next and final steps. Lastly, if your institution or institutions have a press office, please let them know about your upcoming paper now to help maximize its impact. If they'll be preparing press materials, please inform our press team within the next 48 hours. 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. You will receive an invoice from PLOS for your publication fee after your manuscript has reached the completed accept phase. If you receive an email requesting payment before acceptance or for any other service, this may be a phishing scheme. Learn how to identify phishing emails and protect your accounts at https://explore.plos.org/phishing. If we can help with anything else, please email us at customercare@plos.org. Thank you for submitting your work to PLOS ONE and supporting open access. Kind regards, PLOS ONE Editorial Office Staff on behalf of Dr. Paulo H. Pagliari Academic Editor PLOS One https://doi.org/10.1371/journal.pone.0335625.r006

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