Isotopic Signatures of Nitrogen in Selected Soils from Croatia

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

There are 2 things you should review in the article:

1. Discuss with the editorial board whether it is allowed to display the email addresses of all research participants, because I know there are some academic journals that only accept the corresponding author's email address. Other authors will not be allowed to leave personal email addresses in the article.

2. The reference list must be reformatted according to the correct format for reference documents, because when I read the reference list, I saw that you wrote this list but did not format it according to the correct standards of international.

Author Response

Dear Reviewer,

Thank you very much for the time that you have taken to review our paper. After the final decision we will discuss with the editorial board regarding the display of email addresses of authors. The reference list was reformatted, especially those previous listed from No. 34 to No. 47 in order to meet international standards.

 

Kind regards,

Authors

Reviewer 2 Report

Comments and Suggestions for Authors

The review of the paper entitled “Isotopic Signatures of Nitrogen in Selected Soils of Croatia” is complete and the report is given as below:

Research on different isotopic signatures of Nitrogen present in the environment to understand the complexity and the mechanism involved in global biogeochemical cycle. The paper is nicely written and the authors have added some valuable information in this domain. However, the paper can reach a greater audience if it is being modified in following ways:

1.     The theoretical  background concentrating on the importance of the study needs to be improvised.

2.     LSD and p values are missing in the tables and figures which needs to be incorporated. Inclusion of these statistical values highpoints the significance of the data which otherwise is difficult to accept a scientific data

3.     Conclusion: What is the technical value of your knowledge gain? Please highlight it.

Recommendation: Paper may be accepted after minor revision.

 

Author Response

Dear Reviewer,

Thank you very much for the time that you have taken to review our paper. The comments are indeed a great contribution to the paper. The importance of the study was improvised (lines in revised manuscript  from 90 to 98 - marked yellow). Regarding the statistical analyses (one-way ANOVA and post hoc test) we are very much aware that those results would contributed to the considerable importance of the presented results, but regarding the fact that research did not include the equal number of samples for each land use (arable land/crop production, meadow, forest, orchard, ski slope, urban soil/city roads) such statistical analysis could not be performed. But, from our point of view, statistical analysis was not so important for this research because research aimed to determine the origin of nitrogen in each observed soil sample based on the δ¹⁵N abundance and to to discuss and explain the reasons for such origin. That's why we supplemented the research objective (lines 100-101). Conclusion was also supplemented (lines 376 to 379 - marked yellow).

 

Reviewer 3 Report

Comments and Suggestions for Authors

I would like to thank you for the opportunity to prepare the review for this interesting paper.

The manuscript is well done and complete although I suggest trying to add some more recent literature to compare the data. In addition, the authors should report, if possible other data such as environmental or economic data on the impact of the different sources of N. 

Just small remarks that can be useful to the authors: please add the name of the author/s who described the species and the Order and the family e.g. line 151 it should be Quercus pubescens Willd. (Fagales: Fagaceae)

Comments on the Quality of English Language

The English is readable and clear. 

Author Response

Dear Reviewer,

Thank you very much for the time that you have taken to review our paper. All comments were considered. Recent literature (from 2020 and 2023) was added in theoretical background (lines 89-90 - marked yellow, three new references), as well added to the discussion (lines 252-254; 266-271; 335-338; 341-346 - marked yellow, four new references), along with correctly specified forest plant species (lines 161-162 - marked yellow). At the end of discussion environmental or economic data of nitrogen fertilization were added (lines 356 -369 - marked yellow).

Kind regards,

Authors

Reviewer 4 Report

Comments and Suggestions for Authors

Studying the N15 isotopic signatures in different soil types, based on type of land use was thoughtful, however study needs more soil samplings to come to such conclusions.  Sampling from Arable soil is okay, but other types of soil lack the similarity. The number of soil samples considered in the study cannot be considered statistically significant, especially for an observational or correlation study. Also providing the soil sampling strategy or “Soil Analysis Plan” would have strengthened the manuscript.

 

Specific comments:

Line 13, Abstract: Please change it to “correct and distinct”, makes more sense.

Line 14: Correct as “pointed out”. Line 36: “Stable isotope”.

Line 48: What is “demined ratio”?

Line 138: It is not clear exactly what soil was referred to as CONTROL SOIL. As soil samples were collected from geographical sites for study, it is confusing to read “soil samples were also selected from control treatments”. It raises further queries such as, what were the soil treatment in the experimental soil?

Table 1 and Table 2 could be merged, as Table 2 already contains valuable information from Table 1. Looks like Table 1 just shows Average values.

Both Table 2 and 3 summarize the data which are already published by authors of current manuscript. If so, they must not be presented as Table in the main manuscript, could be moved to supplementary information or cited as reference.

While comparison of the Mean δ15N abundance in soils according to different land use was the main finding of the study, soil sample numbers were not constant or comparable. For some categories of soil (Orchard, ski slope) only one sample was analyzed.

 

 

Comments on the Quality of English Language

Editing of English language is needed.

Author Response

Dear Reviewer,

Thank you very much for the time that you have taken to review our paper. We are very much aware and we understand you concern regarding the inconsistencies in the number of samples among different land use. From our point of view this manuscript provides the first look at the utility of soil nitrogen isotopes quantified in selected soils of Croatia. Although, research was based on only 27 soil samples, we believe that represents a valuable initial database and provides important insight for future studies that will confirm and expand the knowledge generated by this investigation. In addition, it provides support for continuing the use and research of all classes soil land use and δ¹⁵N in future in Croatia. Initial idea was to start with samples that were already been in focus of our previous research and to cover all Croatian regions with samples that already existed in our archive. In Croatia there is only one ski resort where world cup races are held, and that one was included in investigation, there were no other ski resorts. Of course, there are lands with other ways of use (orchards, meadows, city roads), but they can be sampled in future research, or if you insist additional, but that would take quite time to conducts the sampling, prepare and analyse samples and to conduct statistical analysis of data, ect.  All specific comments were taken in consideration and marked yellow in manuscript. From table 2 MAT and MAP were removed. Table 2 and table 3 summarize the data which are not already published, data refer to some master thesis and reports which were not publish in scientific papers, and all chemical analysis of presents soil samples from table 3 were conducted by authors, especially first author. Therefore, we suggest that they remain as a part of the Materials and methods as an addition which describes the properties of the observed soils.

Kind regards,

Authors

 

Round 2

Reviewer 4 Report

Comments and Suggestions for Authors

Thanks for explaining the sampling plan used for soil analysis in the current manuscript. The authors have provided fair reason, overall aim and future benefit of this article in the "Reviewer's response file". Such clarity must also be provided in the manuscript. 

I suggest adding some of these explanations in the soil sampling section (2.1) of Materials and Methods would add more value to the manuscript. Future implications of the work, and thus its importance can also be added to the "conclusion".

Discussion section has improved substantially.

Author Response

Dear reviewer,

Once more, thank you for all your efforts and comments. Suggested was added in Materials and methods (lines 104-111, grey marked lines) and in conclusion (lines 384-388, gray marked lines).

Kind regards,

Authors