Innovative Tools for Nitrogen Fertilization Traceability in Organic Farming Products: A Cauliflower Case Study

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

REVIEW 

 

Innovative tools for nitrogen fertilization traceability in organic 2 

farming products: cauliflower’s case study . Campanelli et al.

 

The authors stated that “it has been demonstrated that only a multivariate approach is able to correctly classify the 100 % of the grouped cases.”

 

First question that comes to me is how much (quantitatively) this multivariate approach was superior to a univariate comparison of d15N of plant tissues? Or the others parameters like Brix and Polyphenols?

 

Second, the multivariate model showed a high relevance to d15N of Soil. However, there is a great chance that it has been a bias due to the inclusion of the treatment “agroecological” in the comparison that showed a much higher d15N of soil. This treatment is an agricultural system much longer than the treatments in comparison (20 y vs. 2 y), and In my opinion, this treatment shouldn’t be into the model. It is well known that the manure and compost (organic amendments) a much larger influence in the d15N values of SOC than the synthetic N-fertilizers (The “agroecological” treatment was loaded for years with manure in the past, wasn’t it?). And, the synthetic N-fertilizer has a much larger influence in the 15N-natural abundancy of plants than N from manure or compost because the high solubility of the first. Thus, the appearance of d15N of soil in the multivariate model sounds a bias. I suggest to the authors to consider running the model w/o the “agroecological treatment” and compare the results.

 

Other comments:

 

Fresh weight is in inverse with Brix? Is it normal, isn’t it? They are always  inversely correlated , right? Please, clarify this. 

 

L. 322-327. Please, explain in detail the ac. ascorbic results from “agroecological” treatment. What the reference 44 indicates as a cause? Has this result relation with pathogens pressure too?

 

L358-359. If the was no statistical difference you should only say this. We should avoid to emphasize the different values (means) when there is no statistical difference. Please, delete this part, only refers to Figure 1.

 

L456-457. Please, delete or re-write this sentence due to the same reason pointed above.

 

Figure 3. I suggest to mention and discus the higher dispersion of mix treatments data (as shown in Figure 1). This effect is found in mix cultivation (synthetic N-fertilizers + organic fertilizers or multiple N-sources).

 

L538-543. Please, mention that more the synthetic N applied lower is the d15N of plant parts. 

 

L582-583.. But, only using d15N we could have the same result? (See my first comment).

 

Fig. 6.  There was an overlapping between data from group 1 and 2. There was no clear differentiation, right?

 

Please, clarify to us if Brix and Polyphenols parameters are subject to alterating during transportation, storage, etc.?

 

After considering the comments and suggestions above, I recommend the publication of the manuscript.

 

Very good work. 

 

Best regards,

 

Author Response

Thanks for your comments and suggestions. See a point-point list of answers in the attached file

Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

I request the authors to complete the following information:

Introduction

¾    For the first time used in the text the abbreviation - δ15N should be explained (in addition to the abstract)  (line 83)

Methods

¾    Line 97 - „placed on as many fields nearby, were compared” How many experimental plots (treatments?) were used in the experiment?

¾    What was the previous use of the soil?

¾    Fertilization treatments are very diverse and thus unreadable. Perhaps it would be useful to present them in tabular form?

¾    In my opinion, it is advisable to provide a list of all the analyses performed first.  Otherwise, the reader is baffled by the description of the methodologies of subsequent analyses.

¾    Line 135: What does "stable isotope ratio analyzed were perfomed" mean ? Which isotopes? Were other soil analyses performed?

¾    Line 136: How the soil samples for analysis were prepared? In what quantity were they taken from each treatments?

¾    Indicate the country of origin of the equipment used in the experiment (Zwick/Roell DO-FB0.5 TS ..... etc.).

¾    In how many replicates were chemical analyses performed (pH acidity, ascorbic acid ... etc.). In each year of the experiment?

¾    Indicate the country of origin of the equipment used in the experiment (Zwick/Roell DO-FB0.5 TS ..... etc.).

¾    In how many replicates were chemical analyses performed (pH acidity, ascorbic acid ... etc.). In each year of the experiment?

¾    In what material was total and inorganic N content tested? In how many repetitions? In how many years? Without this information, it is difficult to reproduce the experiment

Results

¾    Line 296 - „soil fertility has been improved (from 1.1% to 1.8%)” – what does it mean?  Was soil fertility studied in this experiment?

¾    Table 3 does not include statistical analysis

¾    In the second part of the chapter (especially 3.5.4 and 3.6) there is practically no discussion element.

¾    The References chapter should be prepared according to the editorial requirements

Author Response

Thanks for your comments and suggestions. See a point-point list of answers in the attached file.

Author Response File: Author Response.docx