Hydrological Properties of a Clay Loam Soil as Affected by Biochar Application in a Pot Experiment

Round 1

Reviewer 1 Report

Dear Authors,

Thank you for submitting your manuscript. However, I struggled finding the right novelty in this research. The weakest point of this research is that it was set up as an 18-pot experiment/artificial conditions instead of testing the biochar application in the field conditions in the fine-textured soils. Moreover, a similar research at the same experimental field/study side was already conducted by authors’ colleagues by Catellini et al., 2015, DOI: 10.1016/j.still.2015.06.016, which they set up as a prerequisite to field experiments. This publications is even not listed in the references. Any other relevant publications might be missing or which have already covered the topic?

I would suggest that this research could be used as an essential preparation prior to the upcoming field experiment (which if I understood correctly you’re planning soon) that can be integrated for the field manuscript, but not as a separate research.

However, if my conclusion is not supported and this paper goes through, here are the comments in order to improve the manuscript:

• Please check the abbreviations: Make sure it is introduced only once as early as possible, e.g. nitrogen, phosphorus etc.
• Overall, a good polishing of grammar and especially punctuation is needed
• Please avoid “respectively”, it is understandable from the context
• Please avoid “As showed in Table 2” and similar, just bring it to the end of the sentence …(Tab. 2); the same goes for Figures.
• The manuscript can be improved by shortening and making the manuscript “sharper”
• Materials and Methods: Fig1 related text needs to be improved and shorten , e.g. it can re-written to “In order to explain applied methods and performed measurements, the sequential phases that were followed from soil and biomass sampling and preparation to measurements, followed by interpretation phase”
• Please call “soil samples” and not “the soil used in the experiment”
• Lines 108-109 any references can support this statement?
• Lines 99-104, please re-write and improve
• Table 1, please explain EC as it has been only introduced below in line 171, hence, provide full names plus abbreviations in the table
• Table 2, please add a separation between two main blocks of tables. Do all those parameters are really needed? Please keep only what has been used within the research aim
• Materials and Methods should be shortened overall
• Overall weak argumentation in lines 681-690

All the best and wish you further success!

 

 

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Reviewer 2 Report

The paper entitled "Hydrological Properties of a Clay Loam Soil as Affected by 2 Biochar Application" reports results from a pot experiment where biochar was mixed with soil and the soil hydrologic properties were determined. The paper is generally well written and at the end a reader understands what authors did and quite understand what authors found. However, I think that the paper must be imporved, especially addressing to some major issues that here I would like to highlight. Further comments (both major and minor) are reproted in the pdf attached.

• My opinion it that introduction should be revised. There are some missing (important) information, such as a brief explanation on the mechanisms that would affect soil structure and hydraulic properties, especially when dealing with contrastinbg soils (see eg comment to L73-77). In contrast, too much emphasis is given to other aspcts that I think are marginal for this research (see e.g. comment on L78-88).
• Moreover, there is some missing informartion, e.g. related to a clear hypothesis that authors want to test with their experiment. Additional details were provided in the pdf attached.
• It follows, from the bullet point before, that there is some confusion between introductory and methodological aspects. Why reporting the hypothesis in methods? See also for instance L252.
• Some methodological aspects must be better justified and or revised, especially regarding sample preparation, saturation procedure and analysis. Additional details were provided in the pdf attached.
• In general, the time is a weak point that should be better taken into consideration: first, it is related to the time span that is requiored for biochar particles to interact with soil and promote cohesion or repulsion: this is weakly discussed and takemn into consideration. The second is about the time of analysis. Just few days for pressure plate determination at -1500 kPa? This must be justified properly because as I understood this is not possible. Additional details were provided in the pdf attached.
• Some better interation between tested parameters can provide a better diascussion, e.g. by merging more the discussion of hydrologic parameters and pore size distribution. Additional details were provided in the pdf attached.
• Improvements of concluding remarks are required to go beyond a simple summary. Authors shopuld try to answer to their hypothesis andn use the resuls to give a single view of what they fopund. This is at the moment laìcking. Additional details were provided in the pdf attached.

 

Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

The article presents a standard study of biochar influence on soil hydraulic properties of one specific soil conducted in laboratory conditions. It describes the changes in bulk density, soil water retention and infiltration velocity. Particularly the results of soil water retention of interest as not many studies have quantified the influence of BC amendment of the entire soil water retention curve. However, some methodological issues have to be clarified. Additionally, vast majority of the results are not discussed and contrasted with the other authors at all. Hence, the authors need to modify the methodological section and include discussion into the manuscript.

Specific comments:

1. l. 14-16: this sentence is the repletion of lines 10-11
2. l. 16: I would avoid the term “capacitive indicator” – never hear of it before. If you refer to its previous use then you can leave it in.
3. l. 110-111: “..literature still report contrasting results..” – document this statement by proper references. The topic is introduced in lines 61-77 but no contrasting results concerning the fine-textured soil are presented.
4. l. 113-116: It would be favourable to justify the use of the utilized soil in the last introduction paragraph.
5. l. 233-235: please add the reason why you have added small quantities of soil to each pot. It could alter your BD calculations.
6. l. 400-422: Even though, you describe quite thoroughly the stepwise approach how you determined model parameters I cannot understand. E.g. step one: “..repeatedly and independently to data from every experimental treatment to obtain specific parameter estimates..” How can you obtain SOME parameter estimates when you declare that it does not depend on data?
7. l. 457-459: it is an interesting statement, which should be discussed and supported by some theory why is this possible.
8. l. 485-86: try to elaborate why you have observed swap of B8 and B10
9. l. 487: cluster analysis should be mentioned in the methods section

Table 5: describe what “Lower” and “Upper” columns stand for

1. l. 526: what is a “saturation” effect on the n parameter. Please specify.
2. l. 573-575: “effect of BC on soil properties is merely additive” this is in contradiction with presented bulk density results (l. 459-460) when you refer to changes in spatial arrangement of BC and soil particles
3. l. 584: decreases in Ksat have to be explained and thoroughly discussed because they generally do not correspond to what is presented in literature for fine-textured soils

Author Response

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Author Response File: Author Response.pdf

Reviewer 4 Report

I found 35 errors of English, either grammatical, spelling or semantic style. I have highlighted these in the attached file. In all other respects the paper is of a high quality.

Comments for author File: Comments.pdf

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Dear Authors,

Thank you for putting some effort to improve the publication. However, I would still suggest that this research could be used as an essential preparation prior to the field experiment that can be integrated for the field manuscript, but not as a separate research. Especially taking into account that specifying the novelty is still challenging and was not specified in the revised version. 

Author Response

Dear Reviewer,

we believe that the amount of information and the detailed surveys conducted can surely help us to better focus on research activities in the open field.

However, we understand your point of view. We are sorry that our manuscript does not have your fully approval and we hope that this not prevent the publication.

Thank again you for your kind consideration.

Reviewer 2 Report

A revised version with actiove track changes  is missing. Could you please provide it for the evaluation of revised vhamges and complete the revision process?

Thanks

Author Response

Dear Reviewer,

we are perplexed to know that you are asking for the “track changes” version of the manuscript.

We can assure you it was done already in the first round of the revision procedure. However, we proceeded again in the same operation.

Thank again you for your kind consideration.

Reviewer 3 Report

The authors have fulfilled all my concerns adequately, so I recommend acceptation of the manuscript.

Author Response

Dear Reviewer,

we are pleased of it!

Thank again you for your kind consideration.

Round 3

Reviewer 2 Report

The authors provided a thorough revision of the paper according suggested revisions, and clarified most of the issues.

Being the paper concerning soil hydrology on a repacked soil that is far from field conditions, my final suggestion is to revise the title to highlight it, e.g. by including significant keywords in the title that better address the reader to what was tested such as "repacked soils" and/or "pot experiment"

A minor comment about the paragraph "conclusions", that usually does not report references. 

Author Response

Dear Reviewer,

We fully agree with you about the suggestion to include a specification in the title of the paper clearly stating that the experiment was conducted in pots, under sieved and repacked soil conditions. It seems appropriate and, therefore, we have followed your advice.

About your last comment, you are right that references are usually not reported in the “Conclusions” section. However, considering our research team has gained considerable experience under that kind of semi-arid climate, with frequent drought periods and low-quality irrigation water, we think that those references could be valuable to some of the readers. Please, give us the chance to leave the citations.

Thank you.

Kind regards,

Angela Libutti