-->PONE-D-26-10820-->-->Impacts of anaerobic cow dung bioslurry-charcoal co-composted fertilizers on tomato (Solanum lycopersicum) productivity and soil properties-->-->PLOS One

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Reviewer #1: Yes

Reviewer #2: Yes

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Reviewer #1: Yes

Reviewer #2: Yes

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Reviewer #1: Yes

Reviewer #2: Yes

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Reviewer #1: Yes

Reviewer #2: Yes

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Reviewer #1: The manuscript with ID: PONE-D-26-10820, title “Impacts of anaerobic cow dung bioslurry-charcoal co-composted fertilizers on tomato (Solanum lycopersicum) productivity and soil properties”. The study addresses an important and timely topic by exploring the reuse of locally available wastes (bioslurry and charcoal) for improving soil fertility and tomato productivity. The integration of agronomic, physicochemical, and multivariate analyses is commendable, and the study has clear relevance for sustainable agriculture, particularly in resource-constrained settings such as Ethiopia. The work demonstrates promising findings and has the potential to contribute meaningfully to the field after appropriate revisions. However, the manuscript requires major revision before it can be considered for publication. The following comments are provided to help strengthen the rigor, clarity, and overall quality of the study:

Major Comments

1. The title should be revised to replace the term “charcoal” with “biochar”, as this is the more scientifically appropriate and widely accepted terminology in the literature.

2. The experimental design lacks clarity, particularly regarding the definition of treatments (T1–T8). A clear mapping between treatment codes and compost formulations should be provided to avoid confusion.

3. The basis for dosage calculations (t ha⁻¹ to kg pot⁻¹) is not sufficiently explained. It is recommended that the conversion procedure be clearly shown to ensure reproducibility.

4. The use of a randomized complete block design (RCBD) is stated, but the blocking factor is not described. This should be clarified, or the design reconsidered if blocking was not meaningfully implemented.

5. The replication level (n = 3) is relatively low for greenhouse experiments. A justification (e.g., statistical power or precedent) should be included.

6. Some measured values, particularly electrical conductivity (EC), appear unrealistic (e.g., values exceeding 1000 mS/cm). These should be carefully rechecked, and units should be standardized (preferably dS/m).

7. The statistical analysis section is insufficiently detailed. The statistical model, assumptions (normality, homogeneity), and post-hoc tests should be clearly described.

8. The reporting of p-values (mostly as p < 0.001) appears overly generalized. Exact p-values or appropriate ranges should be reported where possible.

9. The very high coefficient of variation (CV) values reported in some tables (e.g., >100%) raise concerns about data reliability and should be verified.

10. The interpretation of PCA results tends to imply causation, whereas only associations can be inferred. The language should be revised accordingly.

11. The manuscript merges results and discussion, leading to redundancy and reduced clarity. It is recommended that these sections be separated.

12. The manuscript would benefit from incorporating recent literature on the broader benefits of biochar, particularly its role not only in soil fertility improvement but also in mitigating biotic and abiotic stresses. For instance, studies such as Fayyaz et al. (2024) 10.21162/PAKJAS/24.30 and related recent work (https://doi.org/10.1007/s42773-025-00521-8; https://doi.org/10.55627/pbiotech.002.01.0972) demonstrate the effectiveness of biochar in suppressing root-knot nematodes and enhancing plant resilience. Integrating such references would strengthen the discussion and better position the study within the current scientific context.

13. The short-term greenhouse nature of the study limits the generalizability of the conclusions. Claims regarding field-scale applicability should be moderated.

14. The data availability statement should be more precise (e.g., repository, DOI), as per journal requirements.

15. Some treatments (e.g., T8 with very low application rate) appear inconsistent and require justification or correction.

16. The manuscript would benefit from clear reporting of variability (mean ± SD or SE) across all measured parameters.

Minor Language Comments

1. Several sentences are overly long and complex, and should be broken into shorter, clearer statements for readability.

2. There is inconsistent use of articles (“a”, “the”), particularly in the introduction and methods sections.

3. The phrase “in the same argument” should be revised to “similarly” or “in line with previous studies”.

4. Some subject–verb agreement errors are present (e.g., “results shows” instead of “results show”).

5. The manuscript contains redundant wording, such as repeated phrases like “promising results,” which should be minimized.

6. Tense usage is inconsistent, especially between past and present tense in the Results section; past tense should be used for reporting findings.

7. Several typographical errors and spacing issues are present (e.g., missing spaces between units and values).

8. Scientific names such as Solanum lycopersicum should be italicized consistently throughout the manuscript.

9. Units are sometimes incorrectly formatted or inconsistent (e.g., mS/cm vs dS/m); standard SI formatting should be followed.

10. Some sentences lack clarity and precision, particularly in the discussion, and should be revised for conciseness and academic tone.

Reviewer #2: This study has a strong conceptual foundation and practical relevance. However, data accuracy and clarity must be prioritized. Addressing the issues above will significantly improve the manuscript’s credibility and increase its chances of acceptance. The statistical analysis requires substantial improvement by detailing the model, assumptions, and post hoc tests, and by reassessing data variability where coefficients of variation are unusually high. Compost characterization should be strengthened by reporting key parameters such as C:N ratio and maturity indicators to support agronomic interpretations. The discussion should be revised to avoid overgeneralization from short-term greenhouse results and include a more balanced evaluation of potential risks such as high pH and salinity effects. Figures and tables, especially Table 5, should be carefully revised for accuracy, clarity, and proper labeling, including sample sizes and error bar explanations. For further comments, see the attached file, please.

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Reviewer #1: Yes: Amjad Abbas

Reviewer #2: No

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Attachments

Attachment

Submitted filename: Comments 20-04-2026.docx

Synergetic effect of bioslurry and charcoal co – composted fertilizers on soil properties and tomato (Solanum lycopersicum) productivity

PONE-D-26-10820R1

Dear Dr. Alayu,

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.

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Kind regards,

Muhammad Amjad Ali, PhD

Academic Editor

PLOS One

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