Water Retention Characteristics of Various Sizes of Expanded Perlite Produced from Two Different Types of Rocks
, Dong-Sung Lee 3,†, Chul-Soon Lim 1, Sang-Phil Lee 4, Jae-E. Yang 5,* and Doug-Young Chung 1,*Round 1
Reviewer 1 Report
Comments for author File: 
Comments.pdf
Author Response
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Author Response File: Author Response.pdf
Reviewer 2 Report
Hereafter are reported my comments on the manuscript entitled “Water retention characteristics of various sizes of expanded perlite produced from two different types of rocks”, submitted to Horticulturae journal.
The manuscript deals with investigating the water retention and several other related properties in different types of perlite, one of the most used substrate in soilless culture. Beside reporting and discussing data on how different particle sizes affects hydraulic properties of substrates, which is a not original issue, the interesting part of this manuscript is related to the definition of pedotransfer functions. The use of such functions is particularly interesting, since determinations on hydraulic characteristichs of substrates are labor and cost intensive, because of the equipments needed and the generally long duration of analysis.
That said, the manuscript can be published, although ameliorations are needed. A concise list of my main remarks is reported below.
- In general, the first main criticism for this manuscript is related to English. I found the reading complicated because of sentences often excessively long and convoluted, and poor use of punctuation. I would suggest an extensive editing of the English, in order to make the language more sound and sentences more clear.
- Please revise abstract, taking into consideration that all abbreviations should be explained at their first use (A and B, WRC, …).
- 44-46: This is not true. All mentioned materials, with exception of rockwhool, have large use both pure and in mixture (eg. peat, coir, perlite).
- 98-103: this sentences, as many others, should be rephrased in oder to make it more sound and make the objective more clear.
- 106-110: I found this sentence very confusing and unclear.
- 112: in Table 1 it looks that the samples used fot the determination were three and not five as reported in the text. Please clarify.
- 145: Please briefly describe the procedure used for porosity determination, beside providing references.
- 162: It should be “Results and discussion”
- 168-172: This sentence is unclear to me as it is written, and it should be rephrased. In addition, it’s unclear to me why Authors use the term “assume” about porosity and BD if those parameters were determined. Authors should refer to the results of porosity and BD determination instead of “assuming”.
- In Figures 1, 2 and 3 Authors report the results for the three samples of each material (namely A and B). This is quite unusual, since generally the samples are just statistical replications of a treatment/factor (a substrate in this case) and they should be averaged to generate a single number/line for the treatment/factor they are sampled from. Error bars or other statistical indexes can be provided in order to give information on the samples variability inside a factor/treatment.
Based on the above considerations, I recommend to accept this manuscript pending minor revisions.
Author Response
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Author Response File: Author Response.pdf
Reviewer 3 Report
Dear Authors, I have to reject this work.
Physical properties of both organic and inorganic growing media, such as perlite, are studied from many years and relative literature is very rich. In this work it not seems to be taken into consideration this kind of deep knowledge on growing media. I invite you to deeply study and revise this work, taking into account similar works and well explaining the novelty of your work in respect to previous work.
I have also some concerns regarding as you not take into consideration to apply the typical water retention curve used for growing media and eventually made some consideration about the differences between the two approaches: soil water retention method vs. growing media water retention method (maybe the true novelty of this work).
Please, pay attention also to references: the reference number 6 is not proper (the cited data is not reported in the referred article).
Kind regards
Author Response
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Author Response File: Author Response.pdf
Round 2
Reviewer 3 Report
Dear Authors, thanks for your kind explanation. The work in clear and can be accepted, but I still think that effective available water for growing media is within -10 kPa (-100 cm or also 120 cm) (or however the water considered usually available) and that under this value the availability or non-availability of water must be still proven (till -1500 kPa), especially if considering also container usage and characteristics. Moreover I cannot still see in your work a clear explanation in respect to use soil RWC analysis method instead of usual growing media methods (that indeed are not so much time consuming). I wonder you treated a growing media as a soil, but it isn't and some more explanation about this are due (root grown in a container is not the same that in soil...). You cited authors, such Raviv, that in their works took into consideration the role of container in respect to water retention curve.
Finally, when speaking about growing media, a fundamental characteristics for a proper management of irrigation is the fraction of easy available water (-10 cm to -50 cm suction) that you have not taking into account.
I suggest you to improve your work taking into account these important aspects so that the usefulness can be improved. Finally I suggest to modify with "non-available water" and pay attention to measuring unit (e.g., line 111: 1000 °C).
Kind regards
Author Response
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Author Response File: Author Response.pdf
