Physical Properties of the Canary Islands’ Volcanic Pyroclastic Materials as Horticultural Substrates

Round 1

Reviewer 1 Report

General:

Volcanic tuff samples were collected and analyzed for plant-relevant water status metrics.  Samples of varying particle sizes were used to predict metrics for tuff samples from a different island based on particle size alone.  There is no consideration of mineralogy or particle shape/roughness.  The manuscript is relevant for this journal and presents some new data on a niche growth media.  Below are two main comments and a list of more detailed comments that the authors may consider addressing:

1      Include a justification for the use of 1, 5, and 10 kPa as arbitrary cutoffs for plant-relevant potentials.  At present, these cutoffs appear arbitrary.

2      The main purpose of this manuscript appears to be the prediction of properties of the La Palma tuff based on samples collected on Tenerife.  It is unclear why that was necessary given that La Palma samples were available and are not difficult to obtain.  It is further unclear why there is no evaluation of the prediction even though it appears as if the analysis provided the data needed to test the prediction.

Specific comments:

L22         It seems as if the majority of the samples were collected on Tenerife and not La Palma.  Why is the stated goal to predict La Palma materials specifically? 

L49         Correct formatting of the volume.  Presumably this should be 1.1 x 10^7 m3.

L51         Redundant sentence.

L66         Grounded or ground?

L76         Blake and Hartge use the more common term: particle density.  Is “real density” the disciplinary term?

L77         The effective porosity is given in units of density in Table 1.  Should this be called “bulk density?”

L79         TPS and Pc don’t appear to be shown anywhere in the manuscript.  Consider deleting metric that were not used for the final analysis.

L82         It would be nice to list the fitted vG parameters.

L86         Correct Pe (see comment above) and state that this porosity is assumed to be equal to the volumetric water content at 0kPa.

L96         Do you mean non-linear optimization? 

L99         Should this be CI or GI?

L99         What is meant by “air-water relations were adjusted?”

L102       What is the relevance of this date? 

L124       Explain in the caption what is meant by “most extreme.”  Smallest and largest particle size?

L145       Correct: Perlite.

L151       Consider rephrasing this sentence.  “Israeli references” is awkward.

L169       Figure 4.  Suggestion: rather than depict a number of fitted curves without showing the  individual data points used for fitting, depict some average curve with confidence intervals.  Also, list the vG parameters somewhere in the text or table.

L171       Unclear: porous spatial distribution. 

L171       Figure 5.  Suggest: do not scale to 100%, but show the unscaled volume ratios which would also highlight differences in overall porosity.

L194       Is the grain-size index the same as the coarseness index CI?

L216       Please explain.  AFP is a fraction of the available pore space. Increasing the height of the rooting container will not change AFP per se, but extend the vertical distribution of water according to the water release curve.  So, increasing the height just means that some part, but not all, of the rooting zone would be well aerated.        

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Reviewer 2 Report

Dear Authors-My comments 1

1) In chapter 2 (line 67) specify the grain size ranges that define the three types of tuffs.

2) In chapter 3, please better emphasize your own achievements of this manuscript as opposed to those of cited authors. I suggest using the surname of the cited author or the name of the research area or the country where the samples come from, before giving in brackets [ ] the cited literature. The discussion is generally very modest (especially & 3.4).

3) I recommend creating a table comparing the physical parameters of tuffs "Picón" and other rocks as horticultural substrates. Of course, this table should be discussed to enrich this very modest discussion of the results. It is not known whether the authors' assessment of the studied tuffs is revealing or biased.

4) The content of the applications does not reflect the results obtained. Only the content from lines 15 to 24 and (in 2 sentences) the quintessential content from line 224 to line 231 can be considered conclusions.

Kind regards

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Dear authors. 

It has been a pleasure to read your manuscript, titled “Physical Properties of the Canary Islands' Volcanic Pyroclastic Materials as Horticultural Substrates”, which I found very interesting and well-structured. It is only one thing, which worries me. "Tuff" is used for ash when it is consolidated. In this case, however, you have "tephra". I think you must clarify that. Finally, Fig. 3 is so local. Please provide a better figure to show where La Palma is in the ocean.

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Dear Authors

1. The authors' response in &2 is surprising. Are people other than the authors responsible for the first original manuscript?

2. The authors' answers always indicate the number of lines of text where the content has been corrected. I expected/expected to provide at least the number of the recommended table.

The responses to my remarks seem to be sloppy. Unfortunately, the politeness of the authors cannot be assessed.

Kind regards