Improving the Oenological Potential of Grapes for Prosecco PDO Sparkling Wine Thanks to Nitrogen Fertigation

Round 1

Reviewer 1 Report

The research is important in view of the current scenario of climate change that is already impacting world viticulture. However, the article presents serious problems that require the repetition of the experiment. The experimental design was inappropriate because it did not consider the repetitions for all the variables in the study. The text is very confused in the definition of repetitions. Apparently, it describes that only for chemical variables three repetitions were considered. However, table 6 also presents ANOVA results for other variables. The text also presents statistical results comparing the yield  (2020 vintage only) among treatments as well as for Starch Roots, Sugars Roots, Starch Shoots and Sugars Shoots, but they could not have carried out the statistical analyzes without repetitions. In addition, tables with results for comparing means using the Tukey test or another test were not presented. The sensory analyzes of the wines did not follow the appropriate methodology for carrying out the statistical analyses; therefore they should not be presented as they do not allow the conclusions mentioned in the article. In conclusion, the repetition of the experiment with the inclusion of the experimental design and adequate repetitions must be carried out to allow the performance of statistical analyzes for all variables studied. Another comments in the atached file.

Comments for author File: Comments.pdf

Author Response

Dear Revisor,

We appreciate your wise corrections, and thank you for giving us many suggestions for future research works too.

Experimental design. We understand that the experimental design is not the most appropriate for robust statistical analysis, but it would be difficult to spit drip irrigation systems in many sectors. Also, block managing would require many hydraulic devices and time for supervision, especially because the experiment was carried out on a private farm. We also clarified the irrigation schedule because we omitted to underline both treated and control plots received the same water amount.

Sampling methods. Certainly, the number of repetitions in different vintages was our fault. We tried to describe the sampling methods in the text as clearly as possible. We also resume in Table 2 the number of vines sampled in each repetition for each measure. We sampled many repetitions also for Starch Roots, Sugars Roots, Starch Shoots and Sugars Shoots (three samples and 5 vines per sample). We hope now is more understandable than before.

Statistical analysis. In Table 2 we added letters as an indication of the Tukey multi comparisons test; different letters indicate the mean value referred to a diverse dataset. In some cases, when no differences were detected from the ANOVA, we omitted letters. We carried out ANOVA for every measure we reported in the paper, except for the tasting evaluation, in which we believed repetitions were insufficient for a complete analysis. We move the tasting assessing chart to appendix A, just mentioning the result in the discussions.

References. We would apologise for our carelessness in reporting the references for the specific methodologies used for the must analysis. We extended the materials and methods paragraph, including the right references.

General text. We reassumed the introduction in a short version, and we grouped all the tables just in two main tables. The discussion also focused on the possible nitrogen effect on plant physiology and grape quality. We deleted several old and equivalent references to simplify the text and shorten the bibliography section.

Author Response File: Author Response.docx

Reviewer 2 Report

The paper titled : “Improving the Oenological potential of grapes for Prosecco PDO sparkling wine production: a case study to face Climate Change thanks to Nitrogen fertigation” submitted by the authors Zanchin et al., studied the effects in berries’ biochemicals of additional nitrogen fertigation for producing white Prosecco PDO sparkling wine in a three year study. They determined the biomass production, energy reserve, and fruit yield in response to the additional fertigation.

There are some things need to be addressed before the publishing of this paper:

1)       What is the main question addressed by the research?

The authors studied the effects in berries’ biochemicals as response to additional nitrogen fertigation for producing white Prosecco PDO sparkling wine in a three-year study. They determined the biomass production, energy reserve, and fruit yield in response to the additional fertigation. Wine is produced by fermenting crushed grapes using various types of yeast as we all know, so improving or modifying the characteristics of the grapes directly affect the wine produced.

2)       Do you consider the topic original or relevant in
   the field? Does it address a specific gap in the field?

The topic is original and is relevant to the field of controlling environmental factors (e.g. fertigation) to produce higher quality grapes suitable for sparkling wine production. The topic is tackling highly competitive issue among wine producing companies in Europe.

3)       What does it add to the subject area compared with other published material?

I feel that the authors should show clearly in the introduction part the novelty of this work.

4)       What specific improvements should the authors consider regarding the methodology? What further controls should be considered?

-        Table 1 should be shown on Lines 139 following its mention directly.  

-        In table 1, explain each “1°” on the table itself, it should be self-explanatory.

-        Line 151, explain in detail, “the starch and the sugar content “ determining method.

-        Line 167, additional and detailed data should be shown about the taste panel procedure and persons done that test and methodology of the test.

-         

5)       Are the conclusions consistent with the evidence and arguments presented and do they address the main question posed?

The conclusion is consistent with the evidence and arguments presented and they address the main question posed , but you need to show the prospect of the work

6)         Are the references appropriate?

·       The old references need to be removed, especially those before 2010, try to focus on the last five years.

·       The number of references need to be reduced (they are 54), its not a review article.

Additional comments:

1.     The title of the paper is very long and need to be shortened and improved.

2.     In the introduction:

-        The introduction is very long and need to be shortened and avoid details, which could be moved to discussion. The introduction is recommended to appear in 4 paragraphs, the last paragraph shows the novelty of the work and the objective. Small paragraphs need to joined together as in lines 32-38.

-        The novelty of the work should be highlighted

3.     The results  

·       Figure 2 need to be enlarged and sharpened

·       Figure 3 need to be sharpened

·       Figure 4 need to be enlarged

I give you major revision.

Comments for author File: Comments.pdf

Author Response

Dear Revisor,

We would appreciated your wise corrections and I would thank you for giving me many suggestion also for future research works.

General text. We reassumed the introduction in a short version and grouped all the tables into two main tables. We grouped all the tables just in 2 main ones. I also resume in each table the number of repetitions and the number of vines sampled in each repetition for each measure. We hope now is more understandable than before. The discussion was also implemented on the possible nitrogen effect on plant physiology and grape quality.

References. We would apologise for our carelessness in reporting the references for the specific methodologies used for the must analysis. We extended the materials and methods paragraph, including the right references. We deleted several old and equivalent references to simplify the text and to shorten the bibliography section (42 references).

Figures. Figures were sharpened, and the text size was increased. We moved the panel tasting chart to appendix A because no statistical analysis could support our statement.

Author Response File: Author Response.docx

Reviewer 3 Report

The work of dr.  Zanchin et al titled 'Improving the Oenological potential of grapes for Prosecco 2 PDO sparkling wine production: a case study to face Climate 3 Change thanks to Nitrogen fertigation' aimed to verify the effects in berries’ biochemicals of additional nitrogen fertigation for producing white Prosecco PDO sparkling wine in the conditions of climate change in Veneto region, Italy.

The manuscript is well-written and the results support the conclusions. However, I suggest that the authors rewrite the article's abstract by reducing the general information from the beginning and introducing more figures about the treatments as they already did in the Conclusions section.

Author Response

Experimental design. We understand that the experimental design is not the most appropriate for robust statistical analysis, but it would be difficult to spit drip irrigation systems in many sectors. Also, block managing would require many hydraulic devices and time for supervision, especially because the experiment was carried out on a private farm. We also clarified the irrigation schedule because we omitted to underline both treated and control plots received the same water amount.

Sampling methods. Certainly, the number of repetitions in different vintages was our fault. We tried to describe the sampling methods in the text as clearly as possible. We also resume in Table 2 the number of repetitions and the number of vines sampled in each repetition for each measure. We sampled many repetitions also for Starch Roots, Sugars Roots, Starch Shoots and Sugars Shoots (three samples and 5 vines per sample). We hope now is more understandable than before.

 Statistical analysis. In Table 2 we added letters as an indication of the Tukey multi comparisons test; different letters indicate the mean value referred to a diverse dataset. In some cases, when no differences were detected from the ANOVA, we omitted letters. We carried out ANOVA for every measure we reported in the paper, except for the tasting evaluation, in which we believed repetitions were insufficient for a complete analysis. We move the tasting assessing chart to appendix A, just mentioning the result in the discussions.

 References. We would apologise for our carelessness in reporting the references for the specific methodologies used for the must analysis. We extended the materials and methods paragraph, including the right references.

General text. We reassumed the introduction in a short version, and we grouped all the tables just in two main tables. The discussion also focused on the possible nitrogen effect on plant physiology and grape quality. We deleted several old and equivalent references to simplify the text and shorten the bibliography section.

Author Response File: Author Response.docx

Reviewer 4 Report

In my opinion, for several reasons, the article “Improving the Oenological potential of grapes for Prosecco PDO sparkling wine production: a case study to face Climate Change thanks to Nitrogen fertigation” should be rejected: The experimental design is not well thought out. Half of the one hectare vineyard was fertigated with nitrogen during summer, while the control half received only mineral fertilisation, which also contained nitrogen, in spring. Both the amounts of nitrogen applied and the application procedure do not allow to make an adequate scientific comparison. In the case of the treated vines, fertigation was carried out (versus fertilization in control vines), which implies the application of water, a factor that is not considered in the results. Moreover, in the control plot, nitrogen (35 kg/ha) was applied from post-harvest to full flowering while the treated plot received only 15 kg/ha of nitrogen in post-harvest and 38 kg/ha in summer, without justification in this regard. In addition, sampling was insufficient and irregular in some parameters, for example, in the case of wood weights only data from two vintages were considered, for starch and sugars in the roots three vintages were measured, for yield/vine parameter only the data from one vintage were considered, etc., which lacks of scientific rigor, showing little representativeness in the results.

On the other hand, the materials and methods section is poorly described, with a lack of appropriate references, making this section confusing for the reader and the experiments difficult to reproduce. Also, the statistics applied were incorrect in some cases. The multifactorial analysis was applied independently of the vintages analysed, which may bias the statistics obtained and there are figures without standard error (see Figure 4), making the results difficult to be correctly interpreted.

Finally, the work carried out is not particularly original nor does it add enough novelty to the field of study. Therefore, for my part, the results lack of adequate scientific quality to be published in this journal.

Author Response

Dear Revisor,

We appreciated your wise corrections and we would thank you for giving me many suggestions also for future research works.

Experimental design. We understand that the experimental design is not the most appropriate for robust statistical analysis, but it would be difficult to spit drip irrigation systems in many sectors. Also, block managing would require many hydraulic devices and time for supervision, especially because our experiment was carried out on a private farm. We also clarified the irrigation schedule because we omitted to underline both the treated and control plot received the same water amount. In addition, we aimed to compare the historical farm management (control plot) with our improved management. Unfortunately, we did not find any comparable manuscripts in the bibliography analysis. Glera is a local variety cultivated just in northern Italy, and Glera nitrogen requirements are very high. The nitrogen supplied emerged from studies conducted by CREA-VE, which were published in national journals.

 Sampling methods. Certainly, the different number of repetitions in other vintage was our fault. We described clearly as possible the sampling methods in the text. We also resume in Table 2 the number of repetitions and the number of vines sampled in each repetition for each measure. We sampled many repetitions also for Starch Roots, Sugars Roots, Starch Shoots and Sugars Shoots (three samples and 5 vines per sample). We hope now is more understandable than before.

Statistical analysis. In Table 2 we added letters indicating the Tukey multi comparisons test. Different letters indicate the mean value referred to a diverse dataset. In some cases, when no differences were detected from the ANOVA, we omitted letters. We carried out two-way ANOVA for every measure we reported in the paper, except for yield and wood weight due to a lack of repetitions. Any statistical analysis was carried out about the tasting evaluation, in which we believed the repetitions were insufficient for a satisfying analysis. We move the tasting assessing chart to appendix A, mentioning the result in the discussions.

The multifactorial analysis considered both the vintage and the treatment effect in those descriptors sharing the same number of items per repetition. The vintage affected some descriptors, such as berries juice quality and the pruning weight mass. However, the vintage effect did not affect other descriptors, such as the roots energy stocks. Finally, our considerations were focused on the divergences among the treatments, which was the aim of the present research study.

References. We would apologise for our carelessness in reporting the references for the specific methodologies used for the must analysis. We extended the materials and methods paragraph, including the right references.

General text. We reassumed the introduction in a short version, and we grouped all the tables just in two main tables. The discussion also focused on the possible nitrogen effect on plant physiology and grape quality. We deleted several old and equivalent references to simplify the text and shorten the bibliography section.

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

Accepted for me 

Author Response

Dear revisor,

We would thank you for accepted the corrections made on the raw version of our manuscript. According to a revisor's suggestions we made the following improvements:

FAA determination reference was added in materials and methods;

Figures and tables were moved following the text indication;

Kind regards

Reviewer 4 Report

The article title “Improving the Oenological potential of grapes for Prosecco PDO: a case study to face Climate Change thanks to Nitrogen fertigation” has improved after revision, however there are still some important aspects that should be corrected before publication.

The Materials and Methods section is still unclear and not properly cited. The authors have extended the methodology paragraphs, including some right references, but the references for some specific methodologies are still missing, which lacks of scientific rigor. This information should be added to the manuscript in order to the experiments can be properly reproduced and the work can be published.

Another important aspect is the way in which the authors cite throughout the manuscript. The numerical citation format implies that a number is assigned to each reference as it appears in the text. In this sense, the authors make several errors in the numbering. For example, in the line 45 of the manuscript, they number two references (9, 10) without the previous four (5, 6, 7, 8) having previously appeared. In lines 63-73, the same happens with the reference number 14, etc. This aspect should be duly corrected before the publication of this work.

In addition, there are other minor aspects that should also be corrected: 

Line 78. Indicate the specific years of treatments in order to 2019 (line 80) has sense.

Line 134-136. Please describe in more detail the employed methodology or add the references that contain the complete procedures.

Line 139-141. Please describe in more detail the employed methodology or add the references that contain the complete procedures.

Line 147-148. Indicate the reason by which different numbers of vines (ten vines per three repetitions in 2020; five vines per three repetitions in 2021) were used for sampling.

Line 156. Saccharomyces cerevisiae should be in italics.

Line 172. The figures and tables that are shown throughout the manuscript should appear after they have been mentioned in the text.

Line 200. Change fertilization by fertigation.

Line 294. Remove the comma after the word “rate”.

Line 337-338. The sentence “After flowering, the control plot received a granular mineral fertiliser spread in a unique passage” should be removed from the conclusions section.

Beware of sub-indices and super-indexes throughout the text. They are missing on several lines.

Author Response

Dear revisor,

We would thank you for had accepted the corrections made to the raw version of our manuscript. We fully agree with your issues that emerged from the second revision and we tried our best for enriching the text with the missing information and revisioning the order of the references. In addition:

The analysis methodology was improved among lines 137 and 161;

The sub-indices and super-indexes were checked;

Figures and tables were moved following the text indication;

The different number of vines per repetition for wood weight determination was due to a caution issue for sampling the vines the vintage following the hailstorm event;

Author Response File: Author Response.docx