I think this is an interesting study and I carefully completed the review. The authors investigated the effects of N input levels on microbial community and agroecosystem services after straw return. And they tried to explain the relationship between N input and ecosystem services from two aspects: microbial genes abundance and module communities. This work can be accepted with the following modifications.

1. As straw was added in all the treatments in this research, the title“Moderate N fertilizer reduction  with straw return modulates ecosystem services and microbial traits in a meadow soil” might be more proper. 

2. Abstract: It is recommended to add primary data support rather than purely verbal descriptions. And provide the results about other treatments to compare with 0.75N+PK.

3. L29-30 If possible, “N+PK” and “PK” can be changed as “1N+PK” and “0N+PK”, which is more comparable and clear to express the significance of different treatments. 

4. In the introduction, please replenish relative introduction on reduction of N fertilization. 

5. Line 33: “…… N deficiency.” should be “ …… reduction of N fertiliser application .”

6. Materials and methods, Supply references for all the determination methods.

7. In the results, the description of “ with the increase of N fertiliser application” should be “with the reduction of N fertiliser application”, and redescribe relative results”

8. What does mean of “straw biomass” in Fig4?

9. Lines 73-82: This paragraph is intended to express the role of microorganisms in ecosystem services, but needs to complement the examples of previous research.

10. Line 112：It is suggested to add the purpose of this study.

11. Line 297: Add a related version of the R language.

12. In discussion, I recommend supplementing the evidence on the relationship between straw C and N release and greenhouse gases. As we all know, the efficient conversion of straw C and N into SOM rather than CO2 and N2O is a key issue. Adding relevant content can greatly improve the quality of your manuscript.

13. L403-404 It is not clear to show the description of Fig.4.

14. Lines 454-456：It is suggested to revise this sentence.

15. Line 500: Deleting "Interestingly"

General Review: This study investigates the impacts of different N fertilizer rates on maize through a four-year field experiment, exploring its effects on ecosystem functions such as soil fertility, straw degradation, greenhouse gas emissions, and maize yield. The authors introduce the terms “soil multifunctionality” and “multiple ecosystem services” in a small-scale experiment, when in fact these terms are used in large-scale studies, generally in several locations and with many biological replicates. Also, the manuscript introduces the term "ecosystem dis-services" to represent greenhouse gas emissions, a usage that is relatively uncommon. Furthermore, the research focusses too much on "straw return" without including a treatment group without straw return, complicating the ability to draw robust conclusions about its effects on the experiment. The study lacks essential innovation as the impact of varying N fertilizer rates on soil fertility and greenhouse gas emissions is well studied. Despite this, the manuscript provides valuable insights, such as the revelation that reducing N fertilization by 25% yields comparable results to conventional N application while simultaneously decreasing greenhouse gas emissions. Furthermore, the study highlights increased straw decomposition and N mineralization with a 25% N reduction, which was quantified through the assessment of functional genes (cbhI and GH48) associated with fungi and bacteria, respectively. Regrettably, in its current form, I cannot endorse the publication of this manuscript in SOIL. I recommend that the authors reshape the manuscript's perspective, emphasizing the robust findings, avoiding the use of "soil multifunctionality," and consider submitting a completely revised version.

Specifics comments:

1. The introduction section is too extensive and it should be reduced to maximum 2.5 pages with a double space.
2. Line 33: How could this be an N deficiency effect since the 0.75N+PK treatment had a slightly better corn yield than the N+PK treatment and the same amount of straw biomass?
3. Lines 73-74: Please, explain what is an “opaque environment”.
4. Lines 153-154: It's important to address the exact time that the litter bags were left in the field.
5. Lines 209-211: The authors should specify the reference used to calculate the soil multifunctionality.
6. Lines 212-213: The method description indicates that N2O and CO2 emissions were given the same weight as other soil attributes. This means that higher emissions contribute positively to soil multifunctionality. Therefore, the reader may be confused by thinking that higher greenhouse gas emissions generate beneficial effects on the environment, whereas this effect is exactly the opposite. I suggest the authors review how they work with "soil multifunctionality".
7. Line 218: What is a success of DNA extraction? The agarose gel in a electrophoresis can evaluate the DNA integrity, i.e., if the DNA is fragmented or not.
8. Lines 227-228, 238-239: The PCR stages should be addressed correctly as stage of DNA denaturation, repeated cycles of DNA annealing and the final stage of extension.
9. Lines 282-283: There are no RDA results in the main manuscript or in the supplementary material.
10. Lines 294-295: The heatmap was based on a correlation method? Which one?
11. Lines 309-310: Please explain which microbial function. Also, the microbial biomass was sensitive for what? Microbial biomass was increased or reduced? What are the magnitude changes of your treatments?
12. Lines 315 and every time that the term “ecosystem dis-services” is used: I suggest the authors to use the correct terminology of "greenhouse gas emissions" instead of "ecosystem dis-services". This can prevent readers from making wrong associations with the authors' results and increase the manuscript visibility for readers looking for more information on N₂O emissions under different rates of nitrogen fertilizer use.
13. Lines 319-21: This should be moved to the discussion section.
14. Line 332: Figures 1K, 1L, and 1M use the term "mineralization" whereas it should use the term "emission". I suggest the authors change it to avoid the reader's misunderstanding.
15. Line 367 and Figure S3 (supplementary material): The ANOSIM test was used in the NMDS plot and it should be included in the Material and Methods section.
16. Lines 372-373: The multitrophic network seems to be an important result of the authors' co-occurrence analysis. Therefore, it should be included in the Material and Methods section.
17. Line 381: Please include the network topological properties to have a better overview of the number of nodes, edges and the proportion of positive and negative edges.
18. Lines 416 and 419: Figure 3D shows the contribution of fungal OTUs to the soil multifunctionality index. Perhaps the authors made a mistake and referenced the wrong figure. I suggest a review of this part of the results.
19. Lines 433-434: Again, the figure reference is incorrect. I think this result may refer to Figure 3C and 3D. I suggest the authors review whether all results are addressed to their respective figures.
20. Lines 451-492: Weak discussion on the effects of reducing the rates of N application. The discussion is focused too much on N application and not on different N rates.
21. Lines 451-453: This sentence is confusing. The variables soil fertility", "C and N release" and "crop productivity" were defined as ecosystem services by the authors. How are these variables themselves are contributing to the increase in ecosystem services?
22. Lines 473-474: It is important to describe what are the "unintended consequences".
23. Line 493: There is no data from microbial composition (i.e., taxonomy) in this manuscript. It's better to change the title to "microbial abundance".
24. Lines 502-505: What was the C:N ratio on the referenced paper? It's similar to the authors' results? It's crucial to compare the results from the authors with similar results found in the literature.
25. Line 506: I was expecting some discussion about the fungi:bacteria ratio since the 0.75N+PK treatment showed a better result than the N+PK treatment.
26. Lines 516-517: What would be an "adequate N fertilizer"? It is better to inform that the 0.75N+PK treatment showed better results than the N+PK treatment. Moreover, the term "multiple ecosystem services" is not the most appropriate here since both the cbhI and GH48 genes are related to the straw degradation function.
27. Lines 534-535: It's better to discuss your main results and not the methods used in data analysis.

Duan et al. conducted a four-year field experiment to investigate the relationships between soil ecosystem services and microbial traits under varying rates of nitrogen (N) fertilizer application with straw return. The results indicated that a 25% reduction in chemical N fertilizer is optimal for enhancing ecosystem services. This study is interesting, and the findings contribute to nitrogen management following straw return. I have several suggestions to enhance the manuscript's quality:

1. Line 77, “To our knowledge, fertilization-induced changes in microbial communities and functions are fundamental to the regulation of a variety of ecosystem multifunctionalities”, the importance of microbial community is widely acknowledged, so remove “To our knowledge”. Please correct similar statement.
2. Line 126, (2) 25% reduction XXX; (3) XXX
3. Line 138, 4 treatments with 3 replications each?
4. Lines 143-145, please clarify if it is rhizosphere soil or bulk soil.
5. Line 200, the multifunctionality index is simply calculated by averaging the Z-scores of the 15 variables. There is a question, is more greenhouse gas emission better (also see 474-475)?
6. I would recommend the authors check the MS carefully, including English.