Biochar, Vermicompost, and Compost as Soil Organic Amendments: Influence on Growth Parameters, Nitrate and Chlorophyll Content of Swiss Chard (Beta vulgaris L. var. cycla)
Round 1
Reviewer 1 Report
The current study aims to evaluate different fertilization strategies impact on swiss chard crop performance. The experimental design and methods are appropriate and the results properly displayed and discussed.
My concern is that biochar effect is directly compared to compost treatments, and this is not accurate. A lignocellulosic biochar prepared at 650ºC is expected to be very stable and its nutrient content low and not available. Thus, considering this type of biochar as a possible fertilization strategy is a mistake and the lack of effect on plant nutrition in the studied soil (whose N availability is also low) an expected result. When this type of biochar is used as soil amendment, a source of available N should be also incorporated.
Minor comments are indicated in the attached document
Comments for author File: 
Comments.pdf
Author Response
Department of Science of Agriculture,
Food and Environment,
University of Foggia
Via Napoli, 25
71122 Foggia, Italy
28 February 2020
Manuscript ID: agronomy-727378
“Biochar, vermicompost and compost as soil organic amendments: influence on growth parameters, nitrate and chlorophyll content of Swiss chard (Beta vulgaris L. var. cycla)”
Authors: Angela Libutti, Vincenzo Trotta, Anna Rita Rivelli.
Dear Reviewer,
we would like to thank you for the comments and suggestions that have been very useful in order to further improve the quality of the manuscript.
We revised the manuscript in accordance to your recommendations.
Following your kind request, we are resubmitting a new version of the manuscript; every change made has been clearly highlighted in the revised text using the "Track changes" function.
Please find below our considerations, point by point, in reply to your comments.
Sincerely yours,
The Corresponding Author
Angela Libutti
RESPONSE TO REVIEWER COMMENTS
- The current study aims to evaluate different fertilization strategies impact on swiss chard crop performance. The experimental design and methods are appropriate and the results properly displayed and discussed.
Thank you for your valuable observation.
- My concern is that biochar effect is directly compared to compost treatments, and this is not accurate. A lignocellulosic biochar prepared at 650ºC is expected to be very stable and its nutrient content low and not available. Thus, considering this type of biochar as a possible fertilization strategy is a mistake and the lack of effect on plant nutrition in the studied soil (whose N availability is also low) an expected result. When this type of biochar is used as soil amendment, a source of available N should be also incorporated.
Your comment is welcome and we agree with you.
Different results concerning biochar contribution of nutrients can be observed by considering the large differences in the nature of feedstock and the temperature under which the biochar is formed. Biochar is more important as a soil conditioner and driver of nutrient transformation in the soil and less as a source of nutrients.
Our aim was to verify if biochar could exert the first two mentioned functions also with reference to a short crop growth cycle, such as that of Swiss chard. Our results highlighted that biochar didn’t have an impact in these terms. Indeed, we conclude that, in comparison with the composts, biochar benefits on plant nutrition may achieved over time (see lines 409-411 of the manuscript).
Detailed comments:
- Line 67:
differences
We changed “difference” with “differences” (line 67 of the amended manuscript version).
- Line 67:
Please specify the acronym the first time
We specified the acronym Fw as fresh weight (line 67 of the amended manuscript version).
- Line 71
The authors could also consider the following reference to sustaine this sentence.
Gobbi, V., Bonato, S., Nicoletto, C. and Zanin, G. (2016). Spent mushroom substrate as organic fertilizer: vegetable organic trials. Acta Hortic. 1146, 49-56
We considered the suggested reference and added it to the manuscript, both in the Introduction (line 72 of the amended manuscript version) and in the References section (lines 548-549 of the amended manuscript version).
The numbering of all the references was accordingly modified both in the text and in the References section
- Line 84
efficacy
We changed “efficacies” with “efficacy” (line 86 of the amended manuscript version).
- Line 115
L
We changed “Lt” with “L” (line 117 of the amended manuscript version).
- Line 119
Please change "," with "."
We changed “,” with “.” (line 121 of the amended manuscript version).
- Line 221
acronym has been already specified in the materials and methods
We changed “biochar (B)” with “biochar” (line 226 of the amended manuscript version).
- Line 229
The statistical results reported at line 216 should be also reported in the figure 1.
The statistical results reported at line 216 refer to the total number of leaves, as respectively detected at the first and second leaf cut.
Only these data were statistically processed; therefore, we modified the sentence to make more clear this aspect (lines 220-221 of the amended manuscript version).
To avoid confusion, we prefer not to add the statistical results to the Figure 1.
- Line 257
Statistical analysis results should be added in the graphs.
We better explained the statistical analysis by adding the probability levels in the caption of Figure 2 (line 270 of the amended manuscript version).
In our opinion, reporting in each graph all the statistical analysis results (i.e., the value of the F statistic with the relative degrees of freedom for each factor and for the interaction) could make difficult the reading of the figure.
- Line 279
Statistical analysis results should be added in the graphs.
We better explained the statistical analysis by adding the probability levels in the caption of Figure 3 (lines 292-293 of the amended manuscript version).
In our opinion, reporting in each graph all the statistical analysis results (i.e., the value of the F statistic with the relative degrees of freedom for each factor and for the interaction) could make difficult the reading of the figure.
- Line 338
Statistical analysis results should be added in the graphs.
We better explained the statistical analysis by adding the probability levels in the caption of Figure 4 (line 352 of the amended manuscript version).
In our opinion, reporting in each graph all the statistical analysis results (i.e., the value of the F statistic with the relative degrees of freedom for each factor and for the interaction) could make difficult the reading of the figure.
- Line 386
Please put the latin name in italic
We reported the Latin name in italic (line 395 of the amended manuscript version).
- Line 468
I suggest to short the conclusions reporting only the generalizable information on the base of the obtained results
We shortened the conclusions according to your suggestion (line 480, lines 483-485, 490, 494-497 of the amended manuscript version).
- Line 477
apex
We reported the apex (line 489 of the amended manuscript version).
- Line 478
apex
We reported the apex (line 490 of the amended manuscript version).
Thank you for your kind consideration and we really hope our explanations have been satisfactory. Best regards,
The authors
Angela Libutti,
Vincenzo Trotta and
Anna Rita Rivelli
Author Response File: Author Response.pdf
Reviewer 2 Report
The paper is well written and interesting only few things should be implemented as reported in the attached file.
Comments for author File: Comments.pdf
Author Response
Department of Science of Agriculture,
Food and Environment,
University of Foggia
Via Napoli, 25
71122 Foggia, Italy
28 February 2020
Manuscript ID: agronomy-727378
“Biochar, vermicompost and compost as soil organic amendments: influence on growth parameters, nitrate and chlorophyll content of Swiss chard (Beta vulgaris L. var. cycla)”
Authors: Angela Libutti, Vincenzo Trotta, Anna Rita Rivelli.
Dear Reviewer,
we would like to thank you for the comments and suggestions that have been very useful in order to further improve the quality of the manuscript.
We revised the manuscript in accordance to your recommendations.
Following your kind request, we are resubmitting a new version of the manuscript; every change made has been clearly highlighted in the revised text using the "Track changes" function.
Please find below our considerations, point by point, in reply to your comments.
Sincerely yours,
The Corresponding Author
Angela Libutti
RESPONSE TO REVIEWER COMMENTS
The paper is well written and interesting only few things should be implemented as reported in the attached file.
Thank you for your valuable observation.
Detailed comments:
- Lines 140-143
As this information is displayed in table 1, I think that a reference to table 1 in the previous paragraph would be enough
We deleted lines 140-141 according to your suggestion (lines 142-143 of the amended manuscript version).
- Lines 144-145
Move to footnote. Does s.e. refer to standard error?
We moved the lines 144-145 to footnote and made explicit the acronym s.e. as standard errors (line 148 of the amended manuscript version). Moreover, we made explicit the acronym s.e. in all the Table headings and Figure captions of the manuscript.
- Lines 162-164
I don't think this is necessary in the materials and methods section
In our opinion, this information is useful to better define the biochar characteristics and we would confirm the sentence in the manuscript.
Table 2
molar ratio
We deleted (-) after H/Corg ratio
Figure 1
It is dificult to see the diferences. Maybe it would be better to display this information in a table including the statistical results from the ANOVA
Figure 1 refers to the time-trend of leaf number in the two Swiss chard growth cycles. The experimental data were intentionally represented in this way.
In our opinion, a graph is more useful and gives a more immediate information about this time-trend. Moreover, it make visually comparable the results obtained in the two considered cycles.
- Lines 450-451
NO3- -N : NH4+ -N
We changed “N-NO3:N-NH4” with “NO3--N:NH4+-N” (line 461 of the amended manuscript version).
- Line 478
compared to
We changed “than” with “compared to” (line 490 of the amended manuscript version).
Thank you for your kind consideration and we really hope our explanations have been satisfactory. Best regards,
The authors
Angela Libutti,
Vincenzo Trotta and
Anna Rita Rivelli
Author Response File: Author Response.pdf
