Soil Aggregates Are Governed by Spacing Configurations in Alfalfa-Jujube Tree Intercropping Systems

Round 1

Reviewer 1 Report (Previous Reviewer 1)

Review # 3 for manuscript ID: agronomy-2097092

Title: Soil aggregates are governed by spacing configurations in herbage-tree intercropping systems.

Improvements have been made to the manuscript over the course of the reviews. A couple of items still need addressed before acceptance:

1.      Figure 1: Change IP1.5m to IP1.45

2.      Figure 2: Clean up the arrows and shorten text in the boxes. The wording can be expanded on in the manuscript.

3.      Grammar needs improved throughout.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report (Previous Reviewer 2)

The authors have improved the previous version of the manuscript. Therefore, It will accepted in the present form.

Author Response

We thank the reviewer for your hard work, and we revised our paper in the best way as we could.

Reviewer 3 Report (New Reviewer)

I have read the manuscript entitled “Soil aggregates are governed by spacing configurations in alfalfa- jujube tree intercropping systems”. This is an excellent manuscript that determines the optimal spacing configurations for improving aggregate stability while increasing crop yields in alfalfa-jujube intercropping systems. Generally, I believe the manuscript can interest for the journal. Although, I am satisfied with presentation and writing of the manuscript. I would suggest moderate revision and give the chance to the authors to overlook the following remaining errors in the manuscript.

 

1.      Line 13-25: In abstract numerical/quantitative results are missing, provide the main significant results which you received at IP1m treatment as compared to other treatments. 

2.      Relationships between soil aggregate parameters and herbage yield using multiple linear regression equation is also missed in abstract, briefly provide in one line in abstract. 

3.      Line 112-122: What about rain fall?

4.      How many years Alfalfa-Jujube intercropping system was practiced? How many years later you took soil aggregate samples?

5.      How you measured or calculated the soil aggregate destruction rate (SAD)? Please provide the details in material and methods.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

Review: agronomy-1941279

This manuscript presents some interesting data on the impact of intercropping distance on soil aggregate stability. With the many benefits that intercropping systems can provide, more research is needed in this area to better understand the dominant mechanisms. Although timely, this study lacks focus on the methods used to collect, process and test surface aggregates, as well as several omissions of key information. This makes it extremely difficult for the reader to follow along and takes away from the great research that was done in this study. For this reason, I recommend major revisions to the manuscript to allow edits that will address some of the confusion. See comments below:  

Comments

·         L26: define MWD and SAD

·         Figure 1: Enlarge the text

·         L104-108: The objectives in this study are (1) to determine the differences in soil water-stable aggregates under different patterns of herbage-tree intercropping; and (2) to evaluate the relationships between soil aggregate parameters and herbage yield using nonlinear mass fractal dimension (Dm) tools and assess the short-term effects of aggregate stability on soil structure.  For the second objective, how are you utilizing fractal dimension tools? A reference for Pirmoradian et al., 2005 is provided in the references but I don’t see anything in methods how the Dm parameter is calculated or utilized. Dimensional analysis using fractals can be intensive (See example study on aggregated clusters by Papanicolaou et al., 2012). Please provide a detailed description of these methods similar to their study. Papanicolaou, A. T., Tsakiris, A. G., & Strom, K. B. (2012). The use of fractals to quantify the morphology of cluster microforms. Geomorphology, 139, 91-108.

·       Section 2.2. Experimental Design: There are 5 treatments with 3 replicates of each? How many plots are used in this study? n=15?

·         L123: This study was performed from 2013-2020. Long term studies and data are unique so this fact should be highlighted  

·         L130: change to m^3

·       Section 2.3. Sample Collection: Overall this section is unclear. There are three sampling locations in each plot and collected at the 0-10cm and 10-20cm. Those three samples are “aggregated” into single samples for each depth. This would make it a total of 15 plots, with 15 samples at the 0-10cm depth and 15 samples at 10-20cm. I am confused what is meant by the five replicates randomly assigned at each site? Is this at each plot? What depth were these collected?  Provide more details on how these replicates were processed.

·       Section 2.3. Sample Collection: What sieve size was used to screen debris (8mm??) and more importantly, how were the aggregates measured by sieving? Are these samples air dried? Provide details on how the samples were passed through the sieves (SMP or some type of dissociation?). Provide references to these methods.  

·       Section 2.4. Aggregate Analysis: This section needs rewritten to better explain how these samples are being processed. Provide a detailed flow chart of how these samples are processed to see various steps of sieving, drying, etc. sample processing, sieving, etc. See example of flow used by Six et al., 2001 in Figure 1.

Six, J., Guggenberger, G., Paustian, K., Haumaier, L., Elliott, E. T., & Zech, W. (2001). Sources and composition of soil organic matter fractions between and within soil aggregates. European Journal of Soil Science, 52(4), 607-618.

·         Section 2.4. Aggregate Analysis: In L149 it states that the aggregate samples are first air dried, and then in L153 it restates the samples are air dried but are then manually crushed into small aggregates. Define what these small aggregates are. What amount of force was used to crush them? In L151-152 what method was used to remove biochar? Provide reference.

·       Section 2.4. Aggregate Analysis: L154 states the soil samples were sieved to isolate 5mm diameter aggregates. How is this done if the samples were crushed into small aggregates in the previous processing steps?

·       Section 2.4. Aggregate Analysis: In performing the slaking analysis, what size are the six sieves that were used? How were the air-dried slaked samples gently passed through the sieve? Provide method and reference.

·       Section 2.4. Aggregate Analysis: L159 what is the significance of the 7mm sieve? I have seed 8mm used. Provide reference of this method. In L160 would this be better stated as a subsample? Provide reference for how the samples were submersed in water for 10 min. Was DI water used? What is the significance of using 2 min for the dunking time? Some studies have used 5min.  

·       Section 2.4. Aggregate Analysis: Having a 53um sieve as the bottom sieve in the nest would impact water displacement and levels and impose various suction forces on the samples. The impact of adding suction could greatly impact the distribution of aggregates remaining in the various sieves. Provide reasoning on why this sieve size was used and address this limitation.

·       L168: the word where is indented too much

·       Figure 2: why is the data presented for 0-20cm and 20-40cm depts? In the methods it is stated 0-10cm and 10-20cm?

·       Figure 2: provide a scale on x axis. It is confusing when no values are provided and only a relative sense. Why are the <0.25mm size fractions presented as distributions of stable aggregates? Wouldn’t they be unstable or at best a stable microaggregate? It may also be beneficial to have the size fractions presented from top to bottom as >2mm, 1-2mm, 0.25-1mm as it is more commonly presented that way in similar studies.

·       Figure 3: same question as in Fig.2 on the 0-20cm and 20-40cm depths. If lower depths were used, aggregate stability data at these depths are highly variable and don’t reflect management or land use changes, especially in the 7-year time window of your study.

·       Figure 4 & 5: mean weight diameter (singular). Same comment on depths used

·       Figure 6: y axis should be a fraction or percent. What is meant by first and second?

·       Figure 7: Change y axis title to SAD instead of PAD

·     Section 3.4: If you are presenting yield data add in a section to the methods that explains how it was done and processed with dates, etc.

·    Figure 8: What do the units kg/hm2 represent? Use kg/ha. Are these findings presented as dry weight? Please state this.   

·       L488: SMSA is listed twice. Change the second one to SWSA

·       L489: MWD should be singular (mean weight diameter)

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

This study mainly investigates the mechanism responsible for the plant soil interaction impact on the productivity of an orchard-herbage intercropping system. The authors have used important combination of parameters i.e. the soil aggregates stability and plant yield. An important data set has been obtained. However, I have some concerns regarding the drafting of this manuscript which is needed to be improved before publication. The main problem is about the research design, the author used two factors i.e. soil aggregates > 2 mm, 1–2 mm, 0.25–1 mm, and < 0.25 mm and spacing distance i.e. IP1m, IP1.5m, IP0.5m, monoculture CKAL and with jujube CKJU, It seems to be a two factor experiment but the author have mentioned one way analysis, why? It is suggested to double check it and reanalyse the data as a two factor. The results section is a bit too vague and difficult to follow, what exactly the author want to say and some paragraphs are the repetitions, it is suggested to shorten the overall results at least 30%. The discussion part is a bit shallow.

Specific comments:

L46: “differences”

L48: “under harsh environment”

L97: replace “but” with “however”

L107: “to assess”

L116: “10 ̊C”

L130: “m³”

L170: One way analysis?

L182: Replace “under” with “that”

L205-226: repetition, delete it.

L251-272: again repetition.

Author Response

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Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Thank you for the responses provided to comments on the manuscript. Unfortunately, I feel the responses were rushed and many of the comments were not properly addressed or pushed aside using a blanketed comments like "It was a typo". Having so many instances of typos in the first draft submission seems unacceptable and is something that should have been caught before submitting.

One example of this is stating in the first draft that fractal dimension analysis was performed, and then changing it to linear regression equation by saying it was a typo. These two types of analysis are drastically different and seems peculiar to mistype that in the methods.

The other review that was submitted asked about redoing some analysis using 2 factors. This comment was not addressed properly, calling aggregates a research object, and no attempt to explain it or perform multiple factor analysis. 

I suggest that you go back through and read the manuscript and correct English and grammar throughout. Take time and do not rush. An example of this rushing is found when addressing comment 1: 

1.  L26: define MWD and SAD

ANSWER:

Thank you for your suggestion. We have defined the MWD and SAD in abstract.

the word soil aggregate was inserted into the sentence which now reads:

.....increased mean weight diameters (MWDs) and soil aggregate decreased destruction rate (SAD) of water-stable aggregates.

Lastly, the questions I asked on methods of soil and aggregate sampling and analysis were not addressed. Again the excuse for typo was used. These edits drastlically change the methods and it is concerning as to what the actual methods used were.  

Provide a schematic of a flow chart showing how the samples were processed as I asked for in my first review.  I will not review again unless this is provided. 

Author Response

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Author Response File: Author Response.docx