Roles of Microbial Community and Keystone Taxa in Rice Productivity under Green Manuring in South China
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThe manuscript reports the results of an experimental activity aimed at evaluating the effects of green manure on soil microbial community composition and structure in rice cropping system in southern China. The research is valid and interesting for publication, especially because of the large number of measurements carried out to assess microbial community and its functions and because the experiment was replicated in two different locations/soil characteristics.
However, the manuscript needs some improvements in the following elements:
- Line 81 and Line 87: please specify the soil layer investigated and depth to which the soil analyses refer
- Line 90: modify with “annual cropping system was…”
- Line 93: insert the experimental design definition
- Lines 106-108: provide more information on the measurements of dry matter and N supplied with the milk vetch, that is the method utilized and the result in terms of mean and variability. Also a methodology reference for rice yield measurement and statistical analysis should be provided. It would be important to have the data of N uptake by rice to evaluate the reported effect on rice production of N provided by green manure. Have you measured it?
- Figure 1: the hollow block for the mean values is too small and not visible/covered. Insert the n of sample reported in the figure (line 228, 229)
- References: I suggest checking whether other much-cited references on the topic/crop/region can be added and commenting on them in the relevant sections, such as:
o Zhang, X., Zhang, R., Gao, J., Wang, X., Fan, F., Ma, X., ... & Deng, Y. (2017). Thirty-one years of rice-rice-green manure rotations shape the rhizosphere microbial community and enrich beneficial bacteria. Soil Biology and Biochemistry, 104, 208-217.
o Zhang, X. X., Gao, J. S., Cao, Y. H., Ma, X. T., & He, J. Z. (2013). Long-term rice and green manure rotation alters the endophytic bacterial communities of the rice root. Microbial ecology, 66, 917-926.
Author Response
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Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsDear authors,
please improve the discussion.
e.g you have tested N cycling functional genes. What is its correlation with some of N-cycling specific bacterial and fungal taxa that you observe in your study at different taxonomic levels.
Why NX location has significant differences as compared to that of GQ?
Comments for author File: Comments.pdf
It looks okay.
needs moderate improvements.
Author Response
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Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsComments on the manuscript “sustainability-2941712”
Green manure (GM)-rice-rice rotation is an important management practice for improving soil fertility and rice productivity. This study aims to reveal the mechanisms for the increase of grain yield in GM-rice-rice rotation from the perspective of microorganisms. In general, this manuscript performs well in terms of language expression, figure and table production, and data analysis. I believe it can meet the standards of the journal (Sustainability) through the following revisions.
L 12-14: The significance of microbial communities in improving soil fertility and rice productivity should be added in the Abstract.
L 73-74: The research hypothesis should have a clear direction, so the second hypothesis of the Introduction is invalid.
L 77-79: The significance of conducting field experiments at both sites (Gaoqiao village and Sanxianhu village) should be clarified in the Materials and methods.
More importantly, the actual field experiment map and the schematic diagram of the experiment design should be supplemented.
L 488-490: What are the keystone taxa? The Conclusions should answer the research hypothesis put forward in the Introduction.
Author Response
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Author Response File: Author Response.pdf
Reviewer 4 Report
Comments and Suggestions for AuthorsIn the present study, the authors investigated 'the responses of soil biodiversity, bacterial and fungal communities, and their interactions in the GM-rice-rice rotation.' The author did a good job studying the role of 'Green manure' in improving soil fertility and rice yield and the importance of the bacterial community and fungi in facilitating the process. Based on the content of the manuscript and its discussion, I believe it meets the high standards of 'Sustainability'. However, I have a few comments which should be taken into account before the publication of this fascinating research paper.
1. The manuscript requires proofreading (minor editing) by an English speaker or a professional. I think MDPI has this service.
2. Line 92: Can you please explain why the experiments were carried out at different times? Thank you.
3. There is confusion regarding the timeframe of the experiments. Please specify.
4. Fig 6 needs to be improved in terms of resolution.
5. How does the application of 'Green manure' influence the pH level and physical characteristics (structure) of soil? Please provide an in-depth discussion of the impact of this practice on soil properties.
Comments on the Quality of English LanguageMinor English editing is required.
Author Response
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Author Response File: Author Response.pdf
