Reducing Nitrogen Fertilization in Olive Growing by the Use of Natural Chabazite-Zeolitite as Soil Improver

Round 1

Reviewer 1 Report

I suggest not using the abbreviations in the title.

Abstract line 1, this came from nowhere, why new strategies are needed?

Please clearly describe a brief overview of methodology in abstract, your presented abstract is not linked with the sentences above and below each line.

Line 24, but you just said in upper lines that there were no differential results obtained? Then how they improved in zeolite rich tuff?

line 36, replace uptake with uptaken

Lines 63-65, redundant and can be deletd

While the introduction provides the information regarding background and research question, the need for this study is still lacking, there should be a gap statement. 

Please clearly write your objectives.

The authors should better develop a hypothesis. 

The enough old refernces in the first paragraph of introduction can be replaced with the following

• https://doi.org/10.1007/s11368-021-02944-9
• https://doi.org/10.1007/s40093-014-0080-0
•  

Its zeolite or zeolitite? I suggest using zeolite

line 100, experiment

Label the figure 1 with names.

line 132, (see the following description) should be deleted, also check other places

Please clearly describe the treatment plan and how it was carried out? The timing of application, sampling, protocols?

Heading 2.3. analytical techniques is misleading,, delete this

line 231, IRMS= isotope ratio mass spectro.......

There is no description od measurements of soil charactersistics such as SOM in M&M section.

Table 2. Are these the forest soils? The SOM content is too high. I suggest to double check it. 

Please clearly label and combine the figures as A, B, C and D. Also, add description on what does the lower and upper whiskers in box plots show?

I suggest authors to add some of the data in supplementary materials and report only chief data as main file. 

The 15N and 13C data should be rigorously discussed in discussion. At the moment it is too naive.

What could be the mechanisms behind zeolite addition improving NUE?

The overall english langauge must be improved.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and suggestions for Authors

Reducing N fertilization in olive growing by the use of natural chabazite-zeolitite as soil improver

Subject is very interesting and fall within the scope of the journal. The experimental dataset undoubtedly are useful and constitutes scientific values. The presented manuscript deals with the current local problem.

In this paper, we present the results of three years of experimentation (in three dif-92 ferent experimental sites) in which an Italian chabazite-rich zeolitite was used as a soil 93 amendment in olive growing to reduce the fertilizer N input. Basic soil parameters, solu-94 ble anions and nitrogen speciation of soil samples were monitored, as well as Total Carbon 95 (TC) and Nitrogen (TN) and, Δ13C and δ15N were studied for both soil and leaf samples as 96 well as the plant vegetative growth to evaluate the effects of this practice.

General remarks

In order to increase the usefulness of the article, Authors must refer to the following points.

In the Materials and Methods section the following should be completed:

1.    Soil types according to WRB (World Reference Base for Soil Resources 2022 year).

2.    Atmospheric conditions at the locations of the experiments (rainfall, temperature) should be included. This factor is important when using and transforming NH₄NO₃ and (NH₂) ₂CO. It will be helpful in describing the results obtained for sites 1 and 3 of the research.

3.    What was ẟ¹⁵N and ẟ¹³C determined for?

4.    Was ¹⁵N used?

Specific comments

Lines 109-110: remove "a) and b)", respectively.

Line 485: there should be …..Domenico (2020)….

Line 774: remove Domenico, P,.  

Throughout the manuscript, move the table titles above the tables.

Best regards

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

The manuscript presents interesting study on possibilities of nitrogen fertilization reduction. It is very important because of various issues including economic and environmental effects.

The manuscript is quite well prepared, however some parts of the manuscript should be improved.

Line 159 (and further text): 150g to each olive tree of the fertilizer or pure nutrients? Please provide the doses of pure nutrients per tree as well per unit area.

The figures and the tables present results of variability (e.g. box-plots). It is not clear what was individual observation and how many observations were used for calculation. It should be more clearly stated.

Please provide more details which results are based on all three years. It is important because nitrogen deficiency can be stronger in subsequent seasons.

Main sources of mineral nitrogen content in soil are fertilizers and decomposition of organic matter which contains organic nitrogen. Please provide more information how zeolite can increase mineral nitrogen content is soil. Is it possible in long-term?

It would be good if the efect of zeolite was evaluated in time, ie. comparisons between years or trend in years should be examined.  

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

I am satisfied with the revision. Only ask the reviewers to improve the font size on x and y axis of each figure to be easily readable. 

Author Response

Dear Reviewer,

Here we present the revised version of the manuscript “Reducing Nitrogen fertilization in olive growing by the use of natural chabazite-zeolitite as soil improver”, according to your last comments.

Thank you for this suggestion. We have modified the figures in the main text improving the font size on x and y axis.

Authors

Reviewer 3 Report

The manuscript was improved according all my comments. I accept current version of the manuscript, however, manuscript demands minor technical adjusting. Please change the formatting of the manuscript to the requirements of the journal, eg. capital letters in the title, other style for the titles of the subchapters (e. "2.1...")

Author Response

Dear Reviewer,

Here we present the revised version of the manuscript “Reducing Nitrogen fertilization in olive growing by the use of natural chabazite-zeolitite as soil improver”, according to your last comments.

Thank you very much for the advice. We doble checked the format of the journal and we fixed the bugs.

Authors