Soil Depth Can Modify the Contribution of Root System Architecture to the Root Decomposition Rate
Round 1
Reviewer 1 Report
The study is interesting and may be accepted for publication after minor revisions.
Comments for author File: 
Comments.pdf
Author Response
Thank you for your recognition of our work. Meanwhile, thank you for your comments in the pdf file. We have revised the whole paper in detail according to your comments and suggestions of other reviewers.
Reviewer 2 Report
The article has good and comprehensive analysis of root spatial structure of two forest plantations. However there are two serious drawbacks in relation to dead root decomposition rates:
1. In the text, the authors operate and analyze mostly the root mass loss at dead root decomposition in mass units but not with coefficients of decomposition rate (mass loss for a definite time unit) that are presented on Fig. 5 and in Table A2 (last column) only. There is a word mixture of “decomposition” and “decomposition rate” in the text.
2. The declared in the title and dscussed in the text “…Contribution of Root Structure to Root Decomposition” has not been proven according to Figs 6 and 8a. Moreover the type of this contribution is not specified as well.
I propose to the esteemed authors a text reformatting with minimizing or deleting the decomposition part, and accentuating only root spatial structure analysis with few additional figures.
Some specific comments
2.1. Study site. Soil shall be described in more detail (soil profile description and scientific name by WRB classification): your article relates to soil processes. Do not forget forest floor.
Forest stands shall be described also, minimally with dendrometric parameters and, if possible, biomasses of trees’ compartments.
2.2. Experimental design. Method of the root decomposition rate is not described in detail: is it lab decomposition experiment in controlled condition or field one; how you calculated the decomposition rate?
Section 2.4. Root decomposition rate. This section is written unsatisfactory: (a) the term “root decomposition rate” is not defined (in the text it is mixed with “root decomposition”); (b) there is only a function of MASS LOSS calculation without details how dynamics of decomposition RATE as a process (coefficient “k” with dimension day-1, year-1 etc.) was assessed.
Additionally: I think Table A1 should be in the end of this section with units of every parameter.
3. Results. 3.1. The vertical distribution of root structures.
“Dimension” – it is a very wide term; please explain what do you mean – is it “fractal dimension” from Table A1?
“Root connectivity”, “throat”, “coordination number” are not defined in the text (Section 2) and have no unit dimensions on some figures.
Fig 2a. (a) “Volume fraction” is it 0…1.0 ? Please specify; (b) red lines above columns are not visible.
Fig 3. There are no units for parameters on 3a, b, c, e, f, and no word how they were obtained in Section 2.
3.2. Root decomposition rate and root biomass plus Fig. 5. It is too short. Fig 5a and 5b: please add units for parameter values. Please explain in the text in more detail the vertical variation of root decomposition rates in soil profile (Table A2 last column; it will be good to add figure with graph of these variations in the text here): what are ecological driving factors of this variation. It is a more interesting result. Your explanations in Discussion are amorphous: you listed many factors without clear conclusion. I think it can be a result of water deficit in the mid-summer in 0-10 cm layer leading to decrease of dead roots decomposition rate.
Fig 6. Please correct or explain in the legend the meanings of “dimension”, “volume”, and “area”. I repeat: this fig. and Fig. 8a clearly show that there are no effects of all root structure parameters on dead root decomposition.
Fig. 7. (a) Please explain in the text of Section 2 meaning of “contribution rate,%” and how it was calculated. (b) In legend: “The contribution of soil layers and root decomposition rate under different forest types and different soil layers” - contribution to what???
Table A2 (last column): add please dimensions
(hour-1; day-1; year-1;…).
Author Response
Response to Reviewer 2 Comments
Dear reviewers：
Thank you very much for your letter and the reviewer’s comments concerning our manuscript (ID: Forests- 2311562). Those comments are all valuable and very helpful for revising and improving our paper. We have carefully revised the manuscript according to each comment referred by the reviewers. The revised portions were highlighted in the marked-revised manuscript.
Furthermore, during the revision process, we found some mistakes that we hadn't noticed before and marked them in the marked-revised manuscript.
Point 1: 2.1. Study site. Soil shall be described in more detail (soil profile description and scientific name by WRB classification): your article relates to soil processes. Do not forget forest floor.
Forest stands shall be described also, minimally with dendrometric parameters and, if possible, biomasses of trees’ compartments.
Response 1: Thanks for your useful comment. We described the soil in more detail and added tree measurement parameters. Please see the changed in the marked-revised manuscript 2.1. Study site and 2.2. Experimental design.
Point 2: 2.2. Experimental design. Method of the root decomposition rate is not described in detail: is it lab decomposition experiment in controlled condition or field one; how you calculated the decomposition rate?
Response 2: Thanks for your useful comment. Our study was a field experiment in which root decomposition rate was calculated by measuring root mass in soil cores at different root decomposition times. We have added a note in this section. Please see the changed in the marked-revised manuscript 2.2. Experimental design.
.
Point 3: Section 2.4. Root decomposition rate. This section is written unsatisfactory: (a) the term “root decomposition rate” is not defined (in the text it is mixed with “root decomposition”); (b) there is only a function of MASS LOSS calculation without details how dynamics of decomposition RATE as a process (coefficient “k” with dimension day-1, year-1 etc.) was assessed.
Additionally: I think Table A1 should be in the end of this section with units of every parameter.
Response 3: Thanks for your useful comment. We defined the root decomposition rate in this study. At the same time, the paper unified root decomposition and root decomposition rate, and explained in detail how to evaluate the decomposition rate as a process dynamics. Table A1 is placed at the end of this section according to your suggestions. And added the parameter unit. Please see the changed in the marked-revised manuscript 2.4. Root decomposition rate.
Point 4: Results. 3.1. The vertical distribution of root structures.“Dimension” – it is a very wide term; please explain what do you mean – is it “fractal dimension” from Table A1?
“Root connectivity”, “throat”, “coordination number” are not defined in the text (Section 2) and have no unit dimensions on some figures.
Fig 2a. (a) “Volume fraction” is it 0…1.0? Please specify; (b) red lines above columns are not visible.
Fig 3. There are no units for parameters on 3a, b, c, e, f, and no word how they were obtained in Section 2.
Response: Thanks for your useful comment. The dimension here is the fractal dimension in Table A1.
We have included a description of root connectivity in Section 2. And the corresponding units are supplemented.
For numbers with volume fractions ranging from 0 to 1.0, we have added relevant descriptions in Table A1. The red line mentioned in the annotation of the map name is the red line we used to compare the differences among tree species at the beginning. Later, it was removed for the sake of the beauty of the map. However, due to a mistake, the annotation was not removed in time, and now this content has been removed.
There is no unit parameter it is Changshu, there is no unit. We have specific expressions in Table A1.
Point 5: 3.2. Root decomposition rate and root biomass plus Fig. 5. It is too short. Fig 5a and 5b: please add units for parameter values. Please explain in the text in more detail the vertical variation of root decomposition rates in soil profile (Table A2 last column; it will be good to add figure with graph of these variations in the text here): what are ecological driving factors of this variation. It is a more interesting result. Your explanations in Discussion are amorphous: you listed many factors without clear conclusion. I think it can be a result of water deficit in the mid-summer in 0-10 cm layer leading to decrease of dead roots decomposition rate.
Fig 6. Please correct or explain in the legend the meanings of “dimension”, “volume”, and “area”. I repeat: this fig. and Fig. 8a clearly show that there are no effects of all root structure parameters on dead root decomposition.
Fig. 7. (a) Please explain in the text of Section 2 meaning of “contribution rate,%” and how it was calculated. (b) In legend: “The contribution of soil layers and root decomposition rate under different forest types and different soil layers” - contribution to what??? Table A2 (last column): add please dimensions (hour-1; day-1; year-1;…).
Response: Thanks for your useful comment. We added units to the parameters in Figure 5. The vertical variation of root decomposition rate in soil profile is explained in more detail. We have also revised the corresponding discussion section. Thank you for your opinion.
We have corrected and explained the parameter definition.
The contribution rate mentioned in this paper is actually the influence of this variable on the root decomposition rate. We added new references to support our approach.
We added dimension to the last column in Table A2, moved it to section 2, and described it in detail in the results section.
Author Response File: 
Author Response.docx
Reviewer 3 Report
Congratulations on the complex work and the detailed presentation of the results obtained. Good luck with your next research.
Author Response
Thank you for your recognition of our work. We will make more efforts in future research and make more meaningful research. According to the suggestions of other reviewers, we have revised the whole paper in detail.
Reviewer 4 Report
Good lock
Author Response
Thank you for your recognition of our work. We will make more efforts in future research and make more meaningful research. According to the suggestions of other reviewers, we have revised the whole paper in detail.
Reviewer 5 Report
The present work tried to evaluate the effects of soil depth on the structural and physiological characteristics of the root system of two species of conifers (Cunninghamia lanceolata and Pinus taeda). After 12 months of experimentation, the authors suggested that the soil depth parameter would have a direct or indirect impact on the structural architecture of the roots. It turns out that the upper part of the soil would have a positive effect on certain root characteristics (thickness, length, tortuosity, connectivity...). However, all of these parameters would be negatively affected at the level of the deep parts of the soil. As a result, the root biomass could be degraded thus affecting the rate of root decomposition. This rate could vary depending on the composition of the species studied. Overall, the document is quite well written and documented. It reflects a certain consistency in the presentation of the results obtained. Sources and citations of references are consistent with the subject matter.Nevertheless, here are some comments:
- Clarifications on the characteristics of the soil (texture, pH…)! - Choice of species studied? - Period of 12 months?- Reproducibility of results!
Author Response
Response to Reviewer 5 Comments
Dear reviewers：
Thank you very much for your letter and the reviewer’s comments concerning our manuscript (ID: Forests- 2311562). Those comments are all valuable and very helpful for revising and improving our paper. We have carefully revised the manuscript according to each comment referred by the reviewers. The revised portions were highlighted in the marked-revised manuscript.
Furthermore, during the revision process, we found some mistakes that we hadn't noticed before and marked them in the marked-revised manuscript.
Point1：Clarifications on the characteristics of the soil (texture, pH…)!
Response 1: Thanks for your useful comment.We added descriptions of soil texture and pH in the 2.1Study site.
Point2：Choice of species studied? -
Response 2:The selected tree species are local typical afforestation trees and have certain significance for the development of plantation. This content is expressed in the introduction.
Point3：Period of 12 months?
Response 3:The duration of our experiment was up to 12 months, through which the root decomposition rate was measured.This content is expressed in the introduction.
Round 2
Reviewer 2 Report
Dear Colleagues,
1. I did not received your cover letter. Perhaps it is a defect of editorial system
2. You performed only some technical corrections
3. Your citation on WRB is wrong.
Author Response
Response to Reviewer 2 Comments
Dear reviewers：
Thank you very much for your letter and the reviewer’s comments concerning our manuscript (ID: Forests- 2311562). Those comments are all valuable and very helpful for revising and improving our paper. We have carefully revised the manuscript according to each comment referred to by the reviewers. The revised portions were highlighted in the marked-revised manuscript.
Furthermore, during the revision process, we found some mistakes that we hadn't noticed before and marked them in the marked-revised manuscript.
Point 1: I did not receive your cover letter. Perhaps it is a defect of the editorial system
Response 1: Thanks for your useful comment. We have uploaded the Cover letter before. It may be because of the system that you did not receive it. We have uploaded the Cover letter again this time.
Point 2: You performed only some technical corrections
Response 2: Thanks for your useful comment. We made extensive revisions to the manuscript.
.
Point 3: Your citation on WRB is wrong.
Response 3: Thanks for your useful comment. We have modified the citation on WRB in the manuscript. We do not know whether it is correct now. If there is still any problem, please kindly correct it.
Author Response File: Author Response.pdf
