Effects of Carbon Amendments, Tillage and Cover Cropping on Arbuscular Mycorrhizal Fungi Association and Root Architecture in Corn and Cotton Crop Sequence
Round 1
Reviewer 1 Report
General comments to the authors:
Overall idea of the manuscript is commendable. Finding new sustainable agronomy practice and improvement of existing should represent topic to follow for the practitioners and expects. Role of soil microorganisms which form arbuscular mycorrhizal fungi with host species if intriguing and not fully understood. Therefore, this kind of research can fill some gaps in knowledge and aid with important guidelines especially as it deals with such important cultures as corn and cotton.
However, there were some shortcomings in manuscript that in my opinion were not fully addressed by the authors. Some of them would be highlighted in specific comments regarding line of text where they appear. Overall issue is that it is difficult to follow the main idea of article thorough the text. While the field experiment plan was done properly, the link between arbuscular mycorrhizal fungi colonization and corn and other culture performance is not evident. The question is what return does plant get with greater AMF colonization?
Hypothesis were not formed and it is difficult for readers to know from which position were authors approaching this topic. It also adds to the overall impression of understudied topic which is present in introduction part of article.
Some key information’s were missing in material and methods chapter of the manuscript: where (latitude and longitude coordinates) and when was research taken, how long were corn and other cultures grown, climate conditions during trial, were irrigation, fertilization or other practices taken, yield at different treatments?
Carbon cover is mentioned in earlier sections of manuscript yet in some tables (table 4.) mustard, oat and pea were listed? why did you separate these cover crops?
Cotton is briefly mentioned in manuscript yet it appears in conclusions. This is not fully accompanied with evidence from research as beside table 1 (and figure 2 which seems the same) it is not present in results.
Statistical analysis is well executed and it support the findings of the research. Yet I find redundant to display non-significant results (such as in table 2).
Font of tables and graphics should be consistent through the manuscript (Palatino Linotype).
Specific comments to the authors:
L50-53 It is unclear why the biosolids were only mentioned with few references in introduction when this was part of this research?
L67 remove , at the end of this line
L70-72 Brassicaceae should be in italic
L87 remove , before and cover
L88 remove , before and at the start of this line
L88 I find it important to form and state a hypothesis of this research. This would be appropriate position to place if into
Chapter 2. Materials and Methods especially subchapter 2.1. Site Description and Experimental Design is missing some critical information’s (highlighted in general comments) and it should be rewritten and made more understandable for readers.
L105 this seems as crude measure for soil carbon amendments application. Why did you decide to add this amount? DO you know what was the chemical composition of biosolids (did the contain heavy metals)?
L160 Tukey’s post hoc test
L165 this is first mention of when was experiment done. It should be stated in M&M chapter
L172 table 1 should be separated from rest of text
Table 1. Why at CC (crop cover) at year 2021 is there roughly the half of AMF colonization percentage (for both the biochar and biosolids)? Can you provide explanation for this?
Figure 1. I have issue with this figure as results that were presented in it are already visible in table 1. This seems as duplicating of results. Additionally, left graph is missing y axis legend (AMF %)
Figure 2. Also redundant as tis results it is already present in Table 1
Table 3. Why did you investigate root angle and length among other varables? Why is this feature crucial for corn or cotton performance and can you link this to AMF? It seems that it could be more influenced by soil characteristics than soil carbon amendments (especially if they were only applied to the depth of 10 cm)?
L235 Which study do you refer to?
L242 CEC? I suppose you refer to the Cation Exchange Capacity
Author Response
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Author Response File: 
Author Response.docx
Reviewer 2 Report
Manuscript ID: agronomy- 1858327
Type of manuscript: Article
Title: Effects of Carbon Amendments, Tillage and Cover Cropping on Arbuscular Mycorrhizal Fungi Association and Root Architecture in Corn and Cotton Crop Sequence
Authors: Binita Thapa * , Jake Mowrer
Comments and Suggestions for Authors
The objective of this study was to was to determine the effect of carbon amendment, tillage system and cover cropping on association and root architecture of AMF fungi. The study was conducted as three-factorial experiment in which the first was carbon amendments (biochar, composted biosolid and control). The second factor was was tillage (conventional and no tillage) and the third was cover cropping (mix of oat, mustard and winter pea and no cover crop). Results showed that no tillage system and cover crops favor AMF colonization, which is very important for agriculture practice. The research is also interesting in terms of methodology due to the use of technique for evaluating the root system, which is a very difficult task to perform in practice. Such solution may stand a good source material for future investigation. However, manuscript include many inaccuracies or lack of precision, especially in results section.
This research contains a major flaw in the way of describing the results which is not consistant with presented results in tables or figures, also there are some flaws in experimental design, methods and statistical analysis as described below. Authors should work on these points and revise manuscript.
Please find the following issues that may require a change:
Line 91: years of experiments should be added
Material and methods: results showed in tables are not consistent with the presented methodology. Authors showed in table that first experimental factor was tillage system, while methods inform that the main effect was carbon amendments. I suspect an error in the entry in the methodology. Please be consistent
“3.1. Arbuscular Mycorrhizal Fungi Association” this subsection does not inform about association…it should be more precise like colonization or presence
Results, 3.1.: sentences are not true…Authors did not compare results between tillage systems, so please be precise! Also sentence -“An exception occurred for the CC on year 2021 at depth 15-38 cm” is not true - the exception is also for cotton 0-15, CC 2021 0-15 cm, CC 2021 in tillage system, while in no tillage it is for corn 0-15, cotton 0-15, cotton 15-38 cm, CC 2021 15-38 cm…Authors present results as average for tillage systems but the table shows different, so should be consistent. I propose to show the average in table for tillage because interaction is showed on figure…but it would be correct to provide ANNOVA table to understand presentation the results (I leave it to the Authors for reflection)
Figure 2: on figure keep the same markings as in the text e.g. cover (CC), no cover (NCC)
Sentence “Cotton was planted after the harvest of CC in year 2020. Significant differences were observed on AMF root association between plots receiving CC treatment and plots not receiving CC treatment” is not true! Is the figure showing interaction ? if yes the homogenous groups should be checked !
Table 2: does not reflect three factor experiment
Table 3: does not include the significant effect of C amendment and tillage for root architecture at 20-30 cm depth (p=0.0109).
Table 3 P value= 0.0657 the same table 4 (p= 0.0792 , p= 0.0702) it mean ns if Authors compared by Tukey’s test at α ≤0.05
Line 236 “while [56] observed” should be added who? The same in line 239 (Moreover, [19])…
Line 242: CEC ??? should be explained
Line 239-246: Edit the entire paragraph that will not replace from the hyphen “(i), (ii)” or delete dots between…
Line 249-250: „Our study found that AMF root colonization was greater in NT relative to CT which could be due to mechanical disturbances in soil that ruptured the extra-radical mycelium and thereby reduced the viability of potential propagules” what results proved that? I think that this is a theory of Oehl and Koch (2018) and in that way it should be wrote…
Line 251-251: Reader do not know whether it is citations of someone results or just Author’ s results…
Line 266: add author to „In contrast, [63]”
Line 283: OC -should be explained
Author Response
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Author Response File: Author Response.docx
Reviewer 3 Report
Hello Dear,
I like the manuscript.
I would really work on the result section. The tables and graphs are so confused.
Also, please add the chemical analysis for the carbon amendments in the materials and methods section.
For example, what is the pecent of carbon or nitrogen in the biosolid and biochar?
Thank you,
Comments for author File: 
Comments.pdf
Author Response
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Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
Dear authors,
Thank you for reviewed version of the manuscript. Majority of my comments have been addressed through this version. The manuscript is now more understandable to the readers who may be interested in your research. However, some concerns persist. Some of those are technical issues: Lack of line numbers makes difficult to address the issues through the text. Last paragraph in Introduction is bolded, and it should be normal text template. The tables were not placed in the main text near to the first time they are cited, as stated in template. Table header is broken by table position (such with Table 3, 7).
Others are related to the presented results.
I was not convinced by your explanation regarding root architecture link to the AMF colonization in corn. The literature review you did also complies with this judgement. As there is no evident direct link, it is difficult to address the change in this characteristic to the treatment you investigated. In fact, results by your table 5 support this claim since there was not statistically significant effect of this treatments on root characteristics (alpha 10% is not statistically significant – no need for table). Therefore, table 6 which is connected to previous one is redundant. If there is no effect of treatment, there is no need to check the difference among those.
Similar issue is with table 7 and 8. If there is only statistically significant effect of tillage on root characteristics of CC, then that should be looked into and explained further. I see no need to compare root characteristics for non-significant treatments as shown in Table 8.
Some further explanation of this results section is needed in next revision of manuscript. It seems that significance of results (for root architecture) does not follow the amount of presented findings (through the text and in tables). My opinion is that this manuscript can be improved and therefore I would recommend major revision, since it concerns the results section of research. Otherwise this could be addressed through minor revision of manuscript.
Best regards
Author Response
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Reviewer 2 Report
Thanks to Authors for introducing the necessary changes, but the article still needs to be corrected in terms of statistics. ANNOVA table is not well prepared so please check it (table 2 -analysis of variance (ANOVA) results of arbuscular mycorrhizal fungi colonization % at depth 0-15 and 15-38 cm as influenced by carbon amendments, tillage, cover cropping and their interactions at α = 0.05. This table did not contain interaction....it should be be shown in the first column source of variation - C amendment x tillage, C amendment x cover crop, C amendment x tillage x cover crop, tillage x cover crop.
If Authors compare at 0.05 also for the p value 0.0689 it should be marked as ns...Comparison is usually at 0.01 or 0.05 so this value is not statistically significant.
Author Response
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