Nanoagrochemicals versus Conventional Fertilizers: A Field Case Study with Tailor-Made Nanofertilizers for Sustainable Crop Efficiency of Brassica oleracea L. convar. Capitata var. Sabauda

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Summary

Despite the research topic being quite interesting, the authors did not provide sufficient details regarding the methodological approach. Additionally, the Results and Discussion sections require significant improvement. I encourage the authors to address all these points comprehensively. With these revisions, the manuscript will likely be accepted after a couple of rounds of review.

Title

Title requires the use the capitol letter for each world. Furthermore, “capitata” must be written in italics (also in the whole manuscript).

Abstract

Your abstract is well-written, but it is extensively focused on methods. Please reduce the methods description as well the introductive paragraph (lines 12-14). Instead, provide a more detailed commentary on the results, which currently is present only in lines 22-24.

Line 17: Give more importance to the genotype that you are testing. What is? A commercial line? A landrace? “the cultivation of Brassica oleracea L. var. capitata” is too general. Please, be more specific.

Introduction

Introduction section must be synthetized and more focused on laying the basis for presenting Your trial. Within this context, You must provide a paragraph related to cabbage (or Brassica oleracea) in general description. Within this context, I highly recommend adding these works (link below) related to organic, innovative treatments in B. oleracea crops.

10.17660/ActaHortic.2023.1365.10

https://doi.org/10.1016/j.mtcomm.2021.102284

Lines 112-126: You must be more clear and concise, describing the aim of Your valuable trial in 3 lines.

Materials and methods

Subsection 2.1.

Please, provide the localization (geographical coordinates) of the field.

Lines 142-145. Please, provide a more detailed description of the experimental design. Which is its name? Seems to be a split plot with randomized blocks. Specify the number of plants per square meter. Please, provide a detailed description of the experimental factors. How many replicates? Probably, it should be beneficial to create a new subsection focused on the experimental design.

Subsection 2.2.

The title of this subsection is out of context: I suggest You to change with “Soil analysis”.

Within this context, I highly recommend to provide a Table for better presenting the soil parameters.

Subsection 2.3.

Is not informative. Remove all information related to cabbage (from lines 166 to 175) from this subsection. This information should only be discussed in the Introduction. Provide a more detailed description of the variety tested in Subsection 2.3. Furthermore, subsection 2.3. must be moved at the beginning of M&M section (instead subsection 2.1).

“The species selected for the study was cabbage (Brassica oleracea var. capitata), and it was supplied by the Agricultural Development Center”.

Centre Name? Specify the exact name of the Agricultural Development Centre, as well is localization. Which is the genotype name? Provide the specific name or code of the cabbage genotype used. Is a commercial line? If yes, specify the name of the provider. Is a selected material? Clarify if it is a selected breeding line or material. If applicable, include the entry code or identifier used for this genotype.

Subsection 2.5.

“Transmission Electron Microscopy with a Jeol JEM1400Flash (120 kV) equipped with an Energy Dispersive Spectrometer (EDS) (CACTI, Universidade de Vigo).” Please, provide a detailed description of this instrument (provider, company, set up ecc..).

Subsection 2.6.

“Welgro Potassium Plus”: please, specify the company.

Move Figure 2 after Table 2. Because, Figure 2 is a consequence of Table 2.

Subsection 2.9.

Why have You only evaluated the cabbage yield? Why You have no considered other parameters?

Subsection 2.10.

“IBM-SPSS v.21” (IBM Corp., Armonk, NY, USA). Why did you use an old version of this software? Furthermore, which ANOVA test did you adopt? There are several types. How many ways? What is the name of the test?

Results

The results section should be separated from the discussion. The first subsection of the results should focus on cabbage yield. Additionally, the results presented in Table 5 need to be described in detail. For each parameter, provide its range. For example: “Cabbage yield varied from MIN VALUE to MAX VALUE, for treatment X and treatment Y, respectively.” Furthermore, why didn't you provide a principal component analysis to describe the distribution of the genotype in relation to the different nanoparticle treatments?

Discussion

Results are not well discussed. The references that You included are generally discussed. The must be cited for commenting and motivating Your results. There were any limitations on Your study in relation to the expected results?

Lines 337-339: Why didn’t the total concentration of nitrogen change after nanoparticles application? You must provide an explanation due to nitrogen is a crucial macronutrient for plant growth and development.  

Lines 341-344: The total phosphorus concentration significantly increased. Are You sure that is recommendable for plant growth and soil fertility? In fact, Phosphorus toxicity in plants results from a low capacity of roots to downregulate their P-uptake systems. Please, motivate this aspect because phosphorus should be adsorbed, not deposited in the soil.

Conclusion

The conclusion section should focus more on the results, providing a clear takeaway message for the reader. The current version is too introductory. It needs to be more concise and directly emphasize the key findings and their implications.

Comments on the Quality of English Language

Despite the research topic being quite interesting, the authors did not provide sufficient details regarding the methodological approach. Additionally, the Results and Discussion sections require significant improvement. I encourage the authors to address all these points comprehensively. With these revisions, the manuscript will likely be accepted after a couple of rounds of review.

Author Response

Reviewer 1

Summary

Despite the research topic being quite interesting, the authors did not provide sufficient details regarding the methodological approach. Additionally, the Results and Discussion sections require significant improvement. I encourage the authors to address all these points comprehensively. With these revisions, the manuscript will likely be accepted after a couple of rounds of review.

Thank you very much for your comments. According to your comments, we have improved the methodology section and results and discussion.

Title

Title requires the use the capitol letter for each world. Furthermore, “capitata” must be written in italics (also in the whole manuscript).

Thank for your advice. It is done. Additionally, we contacted the supplier of the cabbage variety and they confirmed that it was the Savoy variety. Therefore, the variety in the title has been modified and corrected according to the information we requested from the Viveiros Ecoagro - Explotación e Comercialización Agropecuaria S.L. and the Centro Agrogandeiro of INORDE (Instituto Orensano de Desarrollo Económico):

Brassica oleracea L. var. sabauda instead Brassica oleracea L. var. capitata according to

Nuez, F.; Gomez Campo, C.; Fernandez de Cordova, P.; Soler, S.; Valcarcel, J.V. Coleccion de Semillas de Coliflor y Broculi (Collection of Cauliflower and Broccoli Seeds). Monogr. INIA. Agric. 1999, 120.

This error is due to many commercial suppliers using the term "capitata" for varieties such as Savoy because it has a greater market introduction capacity. However, the correct description for this type of cabbage is Brassica oleracea L. convar. capitata var. sabauda. Therefore, we have modified the title and the information related to this variety in the manuscript.

Abstract

Your abstract is well-written, but it is extensively focused on methods. Please reduce the methods description as well the introductive paragraph (lines 12-14). Instead, provide a more detailed commentary on the results, which currently is present only in lines 22-24.

We have changed the abstract according your comments.

Line 17: Give more importance to the genotype that you are testing. What is? A commercial line? A landrace? “the cultivation of Brassica oleracea L. var. capitata” is too general. Please, be more specific.

The cabbage we are using in our study belongs to a commercial line. In this study, the variety Savoy was used. This variety is developed and commercialized by agricultural companies. In this study, it was provided by Viveiros Ecoagro - Explotación e Comercialización Agropecuaria S.L. with the intermediation of the Centro Agrogandeiro of INORDE (Instituto Orensano de Desarrollo Económico). Commercial lines are selected and cultivated for their uniform and consistent characteristics. Additionally, they are usually highly standardized, ensuring certain standards of quality and performance. This uniformity and standardization make commercial lines ideal for scientific studies and agricultural trials, as they allow for reproducible and comparable results.

 

 

Introduction

Introduction section must be synthetized and more focused on laying the basis for presenting Your trial. Within this context, You must provide a paragraph related to cabbage (or Brassica oleracea) in general description. Within this context, I highly recommend adding these works (link below) related to organic, innovative treatments in B. oleracea crops.

10.17660/ActaHortic.2023.1365.10

https://doi.org/10.1016/j.mtcomm.2021.102284

Thank you for your comments. We have modified the introduction according to your suggestion and we have added the references mentioned.

Lines 112-126: You must be more clear and concise, describing the aim of Your valuable trial in 3 lines.

Thank you very much for your suggestion. We have changed the paragraph according to your advices.

Materials and methods

Subsection 2.1.

Please, provide the localization (geographical coordinates) of the field.

Done

Lines 142-145. Please, provide a more detailed description of the experimental design. Which is its name? Seems to be a split plot with randomized blocks. Specify the number of plants per square meter. Please, provide a detailed description of the experimental factors. How many replicates? Probably, it should be beneficial to create a new subsection focused on the experimental design.

We have improved the paragraph and added information according to your comments. Besides, we have created the subsection 2.3. Experimental design.

Subsection 2.2.

The title of this subsection is out of context: I suggest You to change with “Soil analysis”.

Thank you very much. It was a mistake and it have been corrected. Besides, after corrections this section is now the 2.4.

Within this context, I highly recommend to provide a Table for better presenting the soil parameters.

Thank you very much for your suggestion. However, we consider that adding a table about the procedures for the soil characteristics analyzed is redundant. Instead, we have provided a preliminary list to inform the reader about the and to improve readability.

Subsection 2.3.

Is not informative. Remove all information related to cabbage (from lines 166 to 175) from this subsection. This information should only be discussed in the Introduction.

Thank you very much for your advice. We have moved the paragraph to the introduction section.

Provide a more detailed description of the variety tested in Subsection 2.3. Furthermore, subsection 2.3. must be moved at the beginning of M&M section (instead subsection 2.1).

We have provided more detailed information of the variety tested and we moved the information from 2.3 to 2.1. (at the beginning of M&M).

“The species selected for the study was cabbage (Brassica oleracea var. capitata), and it was supplied by the Agricultural Development Center”. Centre Name? Specify the exact name of the Agricultural Development Centre, as well is localization. Which is the genotype name? Provide the specific name or code of the cabbage genotype used. Is a commercial line? If yes, specify the name of the provider. Is a selected material? Clarify if it is a selected breeding line or material. If applicable, include the entry code or identifier used for this genotype.

We have modified the section 2.3 and moved to e section 2.1 Crop selection, including more specific information: “The species selected for the study was cabbage (Brassica oleracea convar. capitata var. sabauda - Savoy cabbage variety), and it was supplied by the company provided by Viveiros Ecoagro - Explotación e Comercialización Agropecuaria S.L. (32625 Castrelo do Val, Province of Ourense, Galicia, Spain) with the intermediation of the Agricultural and Livestock Center (Centro de Desenvolvemento Agrogandeiro, 32630 Xinzo de Limia, Ourense, Galicia, Spain) of INORDE (Ourense Institute for Economic Development - Instituto Ourensano de Desenvolvemento Económico)”.

We could not get the genotype name from the company Viveiros Ecoagro since commercial cultivars do not usually have it a publicly available.

Thus, it is a commercial line and it is not a selected material.

 

Subsection 2.5.

“Transmission Electron Microscopy with a Jeol JEM1400Flash (120 kV) equipped with an Energy Dispersive Spectrometer (EDS) (CACTI, Universidade de Vigo).” Please, provide a detailed description of this instrument (provider, company, set up ecc..).

The information was added to the manuscript.

Subsection 2.6.

“Welgro Potassium Plus”: please, specify the company.

The information was added to the manuscript.

Move Figure 2 after Table 2. Because, Figure 2 is a consequence of Table 2.

Done

Subsection 2.9.

Why have You only evaluated the cabbage yield? Why You have no considered other parameters?

In our study, we focused on cabbage yield due to its direct importance to farmers and agricultural production. We also evaluated the number of cabbage heads, the size and weight of the heads, and consequently determined cabbage yield. Additionally, to complete the results, we included the calculation of cabbage head density. Other parameters, such as nutritional quality, were also assessed through nutrient content analysis. Regarding environmental impact, soil characteristics were evaluated before and after the treatments (initial and end of the assay).

Subsection 2.10.

“IBM-SPSS v.21” (IBM Corp., Armonk, NY, USA). Why did you use an old version of this software? Furthermore, which ANOVA test did you adopt? There are several types. How many ways? What is the name of the test?

Sorry for the typo, we have corrected the number of the used version.

In subsection 2.10, we employed a one-way ANOVA to compare the differences between the treatments with nanofertilizers and/or conventional fertilizers applied in the experimental plot. This type of ANOVA is suitable for evaluating whether there are significant differences in the means of multiple groups (in this case, the treatments) based on a single independent variable. Additionally, Duncan's multiple range test was used for post-hoc comparisons to determine which treatments had significant differences. Fisher's least significant difference (LSD) test at 5% was also used to compare means with weighted variance. The Kolmogorov-Smirnov test and Levene's test were applied to verify the normality of the data and the homogeneity of variances, respectively, ensuring that the assumptions required for performing the ANOVA were met.

Results

The results section should be separated from the discussion.

Thank you for your comments. We have separated the results from the discussion.

The first subsection of the results should focus on cabbage yield.

We have changed the order of the results sections according to your suggestions.

Additionally, the results presented in Table 5 need to be described in detail. For each parameter, provide its range. For example: “Cabbage yield varied from MIN VALUE to MAX VALUE, for treatment X and treatment Y, respectively.”

Thank you for your comments and suggestions. We have reviewed your observations and would like to clarify the request to include minimum and maximum values for each treatment in the results section.

Standard Deviation vs. Minimum and Maximum Values

Presenting the data using the mean and standard deviation provides a clear understanding of the central tendency and variability of the data. The standard deviation is a widely accepted statistical measure that indicates how dispersed the data are relative to the mean. In our case, for example for treatment 1, cabbage weight of 370 ± 30 g suggests that most of the data fall within the range of 340 to 400 gr, which is sufficient to understand the variability and consistency of the data.

While some cabbages can weigh more than 400 grams or less than 340 grams, these represent extreme cases. Including minimum and maximum values could skew the interpretation towards these outliers rather than focusing on the central tendency and overall variability that is more representative of the data obtained.

For the calculation of yield with minimum and maximum values, in our experiments, we treated the data from the subplots as a single set to calculate the total yield. Including minimum and maximum values for each treatment does not represent the applied methodology, as each subplot replicate is part of a broader data set. By treating the data as a single set, we ensure that the results reflect the overall variability and not the extreme variations within individual subplots. Besides, calculating the yield using minimum and maximum values for each treatment could introduce a misinterpretation of the data. Our methodology aims to provide an integrated and cohesive view of the results, highlighting the consistency and average performance of the applied treatments.

Furthermore, why didn't you provide a principal component analysis to describe the distribution of the genotype in relation to the different nanoparticle treatments?

Thank you for your comment and for suggesting using PCA to describe the genotype distribution in relation to the different nanoparticle treatments. We would like to explain why we did not find it necessary to include PCA in this study.

The primary objective of our study was to evaluate how nanoparticles affect cabbage production and its characteristics, such as yield, head weight, and nutritional content. We used analysis of variance (ANOVA) to determine if there were significant differences between treatments, which allowed us to understand the impact of nanoparticles on these key variables clearly. ANOVA is a robust statistical tool that helps us to compare the means of various treatments and determine the statistical significance of the observed differences. This analysis is sufficient for our specific objectives, as it provided a clear and direct understanding of how each treatment affected the characteristics of the cabbage.

Our study was not focused on genotypic variability. We aimed to evaluate the direct impact of the treatments on cabbage production. While PCA is a powerful tool for reducing dimensionality and observing patterns in complex data, its application was not decisive for answering our specific research questions. Besides, Including PCA could have complicated the interpretation of the results without adding significant value to our conclusions. The statistical analyses performed (ANOVA and mean comparisons) provided sufficient and direct information to interpret the effect of nanoparticle treatments on the variables of interest. Finally, our interest was in obtaining applicable and practical results for agricultural production, specifically in terms of the efficiency and effectiveness of nanofertilizers in cabbage production. Including additional analyses such as PCA, although informative, would not have significantly contributed to the applied objectives of our study.

Discussion

Results are not well discussed. The references that You included are generally discussed. The must be cited for commenting and motivating Your results. There were any limitations on Your study in relation to the expected results?

We have improved the discussion profoundly by trying to avoid loss of information and answering all your questions. We have included new references and discussed them in depth.

Thank you for your comment regarding the limitations of our study. We know that every study has its limitations, and ours is no exception. Below, we detail the main limitations encountered in our research in relation to the expected results:

The study was conducted over a single growing season, which may not fully reflect the long-term effects of nanofertilizer application. The cumulative effects and sustainability of using nanofertilizers need to be evaluated in long-term studies spanning multiple growing seasons.

Our research was carried out under controlled field conditions, which may not capture all the environmental variability that farmers face in different regions and soil types. Factors such as climate, soil structure, and agricultural management practices can influence the effectiveness of nanofertilizers. Additional studies under diverse conditions are necessary to validate the general applicability of our results.

While our study focused on the effectiveness of nanofertilizers in improving cabbage yield and nutritional content, we did not evaluate the potential long-term environmental impacts.

Lines 337-339: Why didn’t the total concentration of nitrogen change after nanoparticles application? You must provide an explanation due to nitrogen is a crucial macronutrient for plant growth and development.

Thank you for your question. The observed lack of significant changes in total nitrogen concentration in soil after nanofertilizer application can be explained by several factors to the nature and behavior of nanofertilizers:

Nanofertilizers, in particular the urea-hydroxyapatite nanoparticles used may release nutrients in a controlled manner over time. This slow release mechanism ensures that N is gradually made available to plants, more closely matching their uptake needs than conventional fertilizers, which typically release nutrients rapidly. This gradual release can result in more efficient plant uptake and reduced leaching losses, leading to minimal changes in the total nitrogen concentration measured in the soil.

Likewise, traditional nitrogen fertilizers are prone to significant losses through volatilization, leaching and runoff, which can lead to fluctuations in soil nitrogen levels. In contrast, the controlled release properties of the nanofertilizers may reduce these losses. Consequently, nitrogen remains available in the soil for longer without significantly altering the total nitrogen concentration, as less nitrogen is lost to the environment.

Lastly, soils have a buffering capacity that can modulate changes in nutrient concentrations. After the application of nanofertilizers, the soil kept nitrogen levels within the buffering capacity, avoiding significant detectable changes in total nitrogen concentration.

All of this information has been incorporated into the discussion of the manuscript.

Lines 341-344: The total phosphorus concentration significantly increased. Are You sure that is recommendable for plant growth and soil fertility? In fact, Phosphorus toxicity in plants results from a low capacity of roots to downregulate their P-uptake systems. Please, motivate this aspect because phosphorus should be adsorbed, not deposited in the soil.

Thank you for your question. We appreciate the opportunity to clarify this important aspect of our study.

The hydroxyapatite nanoparticles act as a source of phosphorus that can be gradually released into the soil. This release mechanism ensures that phosphorus is available to plants over an extended period, aligning with their uptake needs and reducing the risk of immediate phosphorus loss through leaching or runoff. Besides, nanoparticles enhance the efficiency of phosphorus uptake by plants due to their small size and high surface area, which facilitates better interaction with plant roots. This means that even though the total phosphorus concentration in the soil increases, a significant portion of this phosphorus is in a bioavailable form that plants can readily absorb. Also, the soil capacity to adsorb phosphorus plays a fundamental role in preventing phosphorus toxicity.

We know the potential risk of phosphorus toxicity due to the ability of plant roots to absorb phosphorus. However, in our study, phosphorus concentrations were controlled to ensure that they remained within a range that would allow optimal plant growth without reaching levels that could be detrimental. In fact, treatments with nanoparticles were used with doses at half the optimal dose recommended by INORDE. The significant increase in phosphorus concentration observed in our study was within acceptable limits and did not result in any signs of toxicity in cabbage plants.

Conclusion

The conclusion section should focus more on the results, providing a clear takeaway message for the reader. The current version is too introductory. It needs to be more concise and directly emphasize the key findings and their implications.

We have rewritten the conclusion according to your comments.

 

Comments on the Quality of English Language

Despite the research topic being quite interesting, the authors did not provide sufficient details regarding the methodological approach. Additionally, the Results and Discussion sections require significant improvement. I encourage the authors to address all these points comprehensively. With these revisions, the manuscript will likely be accepted after a couple of rounds of review.

Thank you very much for your comments and suggestions. We have deeply improved the manuscript according to your review.

Reviewer 2 Report

Comments and Suggestions for Authors

The article was performed by Agronmy Journal for reviewing, but the name of another journal is indicated on the pages – Environments, that is, the article needs to be reissued using the appropriate template-file.

The article is devoted to the fact that the authors receive nanofertilizers using known methods, test them on the cabbage, come to the conclusion that it has not become worse. The novelty of this investigation is not clear.

 

Introduction:

In my opinion, Introduction needs major processing/ I recommend:

- to reduce the part of text associated with population growth, since it is advisable to apply fertilizers that increase the yield if it simply reduces the cost of harvesting and increases it. It is necessary to reduce the number of references in this part of the article;

 

- to add an analysis of information on the results already known from the literature on the use of hydroxyapatites as carriers for fertilizers. Some of these articles are mentioned by the authors in the text of the article, but there are many more such publications. It would be possible to present in the Introduction a table in which to collect similar information about hydroxyapatite nanoparticles that are used for fertilization, for which crops they have already been used and with what result. Such information should be analyzed before setting the goals and objectives of the study, since much is already known here: how much hydroxyapatites should be introduced, in what form, in which soils it is preferable to do this, etc. Now there is no such analysis in the Introduction, and the proposal for the use of hydroxyapatites is presented in the text as if it comes from the authors, but in fact, the authors simply use what is already known. In this case, the question arises: what is the novelty of this study? This should be disclosed in the introduction.

 

- The purpose of the work unexpectedly includes the task of synthesizing and characterizing hydroxyapatite nanoparticles doped with urea and potassium sulfate using simple, cost-effective and environmentally friendly methods. In this regard, an analysis of already known methods for the synthesis of similar nanoparticles is needed and an indication of how this method differs from the known ones. This should be added to the text.

 

- Cabbage also appears unexpectedly between the tasks of the work, although cereals are usually discussed as a source of nutrition for an increasing population. It is necessary to explain why this particular culture, and in the singular, was chosen as a test object. In this regard, I suggest that the text (lines 166-175) on the reasons for using cabbage be moved to the Introduction from section 2.3, and this section 2.3 be completely removed from the Materials. I draw your attention to the fact that the authors refer to the fact that cabbage is very necessary in Asia, and research is being conducted on soil in Spain and on a variety that is characteristic of Spain. The situation should be explained somehow.

 

Materials and methods:

Figure 2. Distribution of the 32 subplots (S) with their applied treatments (T). It is clear that "same color indicates identical treatment", but it is better to give the color and processing correspondence in the caption to the drawing, as well as explain why the sections are selected in this order / or this is a random order.

 

 Part 2.9, lines 251-256. Why do the authors not associate the appearance of additionalcabbages with the method and dose of fertilization? Maybe this information should not be ignored and transferred to the results and discussions.

 

Figure 1 and Figure 3a are the same thing, so Figure 1 can be deleted.

Lines 251-256: The content of Ca, Fe, Mg and Zn, which were not introduced into the soil, is analyzed, and the effect of introducing fertilizers into the soil on the accumulation of these substances in cabbage is indirect.

 

Results and discussions:

If I understood correctly, and the authors used other people's well-known techniques to obtain nanofertilizers (parts 2.4.1 and 2.4.2), then data from paragraph 3.1 should be compared with previously known characteristics of similar nanoparticles.

 

Table 1 can be presented as a text in the Introduction, which deals with the role of K,N,P for harvesting.

 

Table 3 and 4: it is better to make the letters a, b,c,d superscript.

I suggest reformatting Tables 3 and 4. In one of them, leave the trace elements accumulated in the biomass before and after the application of nanoparticles, and in the other, it would be good to collect soil characteristics before and after fertilization. This will allow for a clearer discussion of the changes before/after and divide the discussion of the impact of the tested approach on the soil and on plants.

 

Table 5: Where is the information on the yield cabbages grown in the control (without fertilizers) and on traditional fertilizers? I don't see her, but she must be there. The Table I wrote about above can help in the discussion/ It is necessary to look at the comparison of the data obtained with other literary data in a tabular version. This makes it easier to compare data. At the moment, all that is clear from the discussion of other studies is that such studies have been conducted, and there are quite a few of them. It is not clear what the authors have done so new? What contribution have you made to what has already been done? If the effectiveness of the approach has been confirmed once again, then it is probably worth citing the characteristics of soils and crops (both your own and others') in order to demonstrate its versatility or to trace how the characteristics of soils/nanofertilizers affect the effectiveness of the approach. The result obtained by the authors must be somehow highlighted.

 

References

There are no references in the article for 2024 and a few references related to 2022-2023.

Typos:

- Reference 48 is marked 1.

- Caption for Tables 3 and 4 – K²O – “2” must be as a subscript.

Author Response

Reviewer 2

The article was performed by Agronmy Journal for reviewing, but the name of another journal is indicated on the pages – Environments, that is, the article needs to be reissued using the appropriate template-file.

Thank you very much for the comment. This is because the manuscript was initially sent to Environments, but the editorial office recommended sending it to Agronomy as it was much more suitable for the topic of the article. The article was transferred directly from Environments to Agronomy.

The article is devoted to the fact that the authors receive nanofertilizers using known methods, test them on the cabbage, come to the conclusion that it has not become worse. The novelty of this investigation is not clear.

Thank you for your comment. Although the methods for obtaining nanofertilizers are established, our study aims to highlight the benefits of applying nanofertilizers compared to the use of conventional fertilizers. Additionally, field trials with nanofertilizers are scarce, and most of them have been conducted in controlled laboratory or greenhouse settings. More specifically, our study contributes to:

Improved nutrient efficiency: Nanofertilizers allow for a more controlled and gradual release of nutrients, ensuring that cabbage plants receive a steady supply over time. This reduces nutrient leaching and increases the overall efficiency of nutrient uptake by the plants.

Environmental impact: By reducing the amount of fertilizer needed and minimizing nutrient runoff, nanofertilizers can significantly decrease the environmental impact associated with conventional fertilization methods. This is particularly important for preventing soil and water contamination.

Increased productivity: Our study demonstrated that the use of nanofertilizers can maintain crop yields compared to traditional fertilizers. This is crucial for sustainable agricultural practices, as it ensures good productivity despite the reduction in the amount of fertilizer applied.

Soil health: The application of nanofertilizers can help maintain soil health by preventing the build-up of excess nutrients and reducing the need for frequent fertilizer applications.

 Introduction:

In my opinion, Introduction needs major processing/ I recommend:

- to reduce the part of text associated with population growth, since it is advisable to apply fertilizers that increase the yield if it simply reduces the cost of harvesting and increases it. It is necessary to reduce the number of references in this part of the article;

We have reduced this paragraph and the references according to your suggestions.

 - to add an analysis of information on the results already known from the literature on the use of hydroxyapatites as carriers for fertilizers. Some of these articles are mentioned by the authors in the text of the article, but there are many more such publications. It would be possible to present in the Introduction a table in which to collect similar information about hydroxyapatite nanoparticles that are used for fertilization, for which crops they have already been used and with what result. Such information should be analyzed before setting the goals and objectives of the study, since much is already known here: how much hydroxyapatites should be introduced, in what form, in which soils it is preferable to do this, etc. Now there is no such analysis in the Introduction, and the proposal for the use of hydroxyapatites is presented in the text as if it comes from the authors, but in fact, the authors simply use what is already known.

Thank you for your valuable feedback. We understand the importance of contextualizing our study within the existing body of research on the use of hydroxyapatite nanoparticles as carriers for fertilizers. We have incorporated relevant information from the literature into the Introduction section to provide a comprehensive background and to highlight the novelty and significance of our study.

Regarding your suggestion to include a table summarizing the use of hydroxyapatite nanoparticles in fertilization, while we agree that such a table can be informative, we believe that it may not be the most appropriate format for the Introduction section. Instead, we have added a detailed narrative that synthesizes the key findings from the literature, including the types of crops, results, and conditions under which hydroxyapatite nanoparticles have been used effectively.

In this case, the question arises: what is the novelty of this study? This should be disclosed in the introduction.

The novelty of this study lies in the development and application of on-demand nanofertilizers for the cultivation of Brassica oleracea L. convar. capitata var. sabauda (Savoy cabbage). Specifically, we have synthesized urea-hydroxyapatite and potassium sulfate nanoparticles to compare these nanofertilizers with conventional fertilizers, focusing on their efficiency in nutrient delivery, potential to reduce environmental contamination, and overall impact on crop yield and quality. This study provides new insights into the behavior and fate of nanofertilizers in soil systems and their effects on cabbage growth and nutrient content through controlled field trials.

We have included a paraghaph in the introduction with all this information.

 - The purpose of the work unexpectedly includes the task of synthesizing and characterizing hydroxyapatite nanoparticles doped with urea and potassium sulfate using simple, cost-effective and environmentally friendly methods. In this regard, an analysis of already known methods for the synthesis of similar nanoparticles is needed and an indication of how this method differs from the known ones. This should be added to the text.

Thank you for your comments. We have revised the Introduction as per the suggestion of another reviewer to remove the detailed reference to "the task of synthesizing and characterizing urea-doped hydroxyapatite and potassium sulfate nanoparticles using simple, cost-effective, and environmentally friendly methods." Consequently, we did not include a comparison of synthesis methods in the Introduction.

- Cabbage also appears unexpectedly between the tasks of the work, although cereals are usually discussed as a source of nutrition for an increasing population. It is necessary to explain why this particular culture, and in the singular, was chosen as a test object. In this regard, I suggest that the text (lines 166-175) on the reasons for using cabbage be moved to the Introduction from section 2.3, and this section 2.3 be completely removed from the Materials. I draw your attention to the fact that the authors refer to the fact that cabbage is very necessary in Asia, and research is being conducted on soil in Spain and on a variety that is characteristic of Spain. The situation should be explained somehow.

Thank you for your comments. We have revised the Introduction to clarify the choice of cabbage as the object of study and to provide relevant production data. In addition, we have moved the relevant text from section 2.3 to the Introduction and deleted section 2.3 of Materials and Methods as suggested.

 

Materials and methods:

Figure 2. Distribution of the 32 subplots (S) with their applied treatments (T). It is clear that "same color indicates identical treatment", but it is better to give the color and processing correspondence in the caption to the drawing, as well as explain why the sections are selected in this order / or this is a random order.

Thank you for the suggestion. We have moved Figure 2 just below Table 1, where the treatments used are indicated. The figure caption now also states that the distribution is random.

Part 2.9, lines 251-256. Why do the authors not associate the appearance of additionalcabbages with the method and dose of fertilization? Maybe this information should not be ignored and transferred to the results and discussions.

Thank you for your comments. We understand the importance of associating the appearance of additional cabbages with the method and dose of fertilization. We have reviewed our data and agree that this information must be added. We include this analysis in the Results and Discussion section to provide a comprehensive understanding of the effects of different fertilization methods and doses on cabbage production.

Figure 1 and Figure 3a are the same thing, so Figure 1 can be deleted.

Thank you for the suggestion. We have deleted the figure 1.

Lines 251-256: The content of Ca, Fe, Mg and Zn, which were not introduced into the soil, is analyzed, and the effect of introducing fertilizers into the soil on the accumulation of these substances in cabbage is indirect.

Thank you for your insightful comment. We agree that the analysis of Fe, Mg, and Zn (Ca is incorporated in hydrohydroxyapatite), which were not directly introduced into the soil, needs to be clarified in terms of their indirect accumulation in cabbage due to the fertilization methods used. We address this point by explaining how the application of nanofertilizers can influence the uptake of these micronutrients in the results and discussion.

 

Results and discussions:

If I understood correctly, and the authors used other people's well-known techniques to obtain nanofertilizers (parts 2.4.1 and 2.4.2), then data from paragraph 3.1 should be compared with previously known characteristics of similar nanoparticles.

Thank you for your insightful comments. In section 3.4 (updated), we have characterized the nanoparticles synthesized in our study using Transmission Electron Microscopy (TEM) and Energy Dispersive Spectroscopy (EDS). We have compared the size, morphology, and elemental composition of our hydroxyapatite/urea and potassium sulfate nanoparticles with nanoparticles documented in studies by Kottegoda et al. (2017) and Dong et al. (2018). These comparisons confirm that our synthesized nanoparticles exhibit comparable and similar properties, supporting the reliability and effectiveness of the techniques we employed.

 

Table 1 can be presented as a text in the Introduction, which deals with the role of K,N,P for harvesting.

Thank you very much for your suggestion. According to your comments and other review comments, we have placed table one in section 2.8 Soil treatments with conventional fertilizers and/or nanofertilizers for a better understanding of the manuscript.

Table 3 and 4: it is better to make the letters a, b,c,d superscript.

Done

I suggest reformatting Tables 3 and 4. In one of them, leave the trace elements accumulated in the biomass before and after the application of nanoparticles, and in the other, it would be good to collect soil characteristics before and after fertilization. This will allow for a clearer discussion of the changes before/after and divide the discussion of the impact of the tested approach on the soil and on plants.

Thank you for your comment. I believe there is a misunderstanding regarding Tables 3 and 4. Table 3 represents only soil characteristics data. The data for P, N, C, and, on the other hand, Ca, Na, K, Mg, and Al are contents of exchangeable cations in the soil and the effective cation exchange capacity. Table 4 represents the same but at the end of the field experiment. Therefore, this table does not contain data related to the crop, only soil data, which is what you suggest in your comment.

Table 5: Where is the information on the yield cabbages grown in the control (without fertilizers) and on traditional fertilizers? I don't see her, but she must be there. The Table I wrote about above can help in the discussion/ It is necessary to look at the comparison of the data obtained with other literary data in a tabular version. This makes it easier to compare data. At the moment, all that is clear from the discussion of other studies is that such studies have been conducted, and there are quite a few of them. It is not clear what the authors have done so new? What contribution have you made to what has already been done? If the effectiveness of the approach has been confirmed once again, then it is probably worth citing the characteristics of soils and crops (both your own and others') in order to demonstrate its versatility or to trace how the characteristics of soils/nanofertilizers affect the effectiveness of the approach. The result obtained by the authors must be somehow highlighted.

Thank you for your comments and suggestions. We appreciate the opportunity to clarify and enhance the presentation of our data. Here is our response to the points you raised:

Yield information for control and traditional fertilizers

The control plots in our study were used to collect baseline soil samples before the application of any fertilizers. Therefore, no cabbages were planted in these control plots, as they were intended only for initial soil characterization. Consequently, there is no yield data for cabbages grown without fertilizers.

We did include yield data for cabbages grown with conventional fertilizers and nanofertilizers. We will ensure this information is clearly presented in Table 5 for better comparison.

Yield data with conventional fertilizers corresponds to the data of treatment 7 and 8 in table 5.

Comparative Data with Literature

We agree that comparing our data with existing literature in a tabular format would facilitate a clearer discussion. We have added a new table that compares our results with those from other studies, focusing on the effectiveness of different fertilization approaches.

Contribution and novelty

Our study contributes to the existing body of knowledge by demonstrating the effectiveness of nanofertilizers in enhancing nutrient uptake and yield in Brassica oleracea under specific soil conditions. Unlike previous studies, we used a novel combination of urea-doped hydroxyapatite and potassium sulfate nanoparticles. We have shown that these nanofertilizers can improve the effective cation exchange capacity and overall soil health, leading to better crop performance, all in a field experiment, these being very limited in the scientific literature. This approach also offers environmental benefits by reducing the need for excessive fertilizer application and minimizing nutrient runoff.

Versatility and soil/nanofertilizer characteristics

We include a detailed comparison of soil characteristics before and after fertilization in our revised Tables 3 and 4. Additionally, we add a discussion on how the specific properties of our nanofertilizers influence their effectiveness. By highlighting these factors, we aim to demonstrate the versatility of our approach and its potential applicability to different soils and crop systems.

 

References

There are no references in the article for 2024 and a few references related to 2022-2023.

We have added new references to the manuscript.

Typos:

- Reference 48 is marked 1.

- Caption for Tables 3 and 4 – K²O – “2” must be as a subscript.

These mistakes were corrected

 

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The authors signifincalty enhanced the quality of the work providing a comprehensive revised version.  

Comments on the Quality of English Language

The authors signifincalty enhanced the quality of the work providing a comprehensive revised version.  

Author Response

 Suggestions for Authors

The authors signifincalty enhanced the quality of the work providing a comprehensive revised version.  

Thank you very much for your review

Reviewer 2 Report

Comments and Suggestions for Authors

I have minor comments to the significantly improved text of the authors:

Line 79:  In the phrase “Similarly, , low” one comma is superfluous.

All names of the authors of the references mentioned in the article (Line92: Kottegoda et al. [34]; Line 97: Al-Uthery and Al-Shami [35]; Line 99: Maghsoodi et al. [27]; Line 101: Sharma et al. [33]; Line 104: Dong et al. [36] ; Line 106: . Sheoran et al. [32]; Line 108: Shalan [37]  ) should be removed, and only the numbers of the references should be kept in the main text. This rule is common and recommended for the authors published in the MDPI Journals. Please, see the recommendations in the "word template".

Similar but not the same situation is in Table 7: Please remove the names of investigators from the column 1, and add only numbers of corresponding references in square brackets to the Table. Now, the numbers of references are absent in the Table at all.  Please, name the column “Reference” instead of “Study” in the Table.

Line 293: Please add explanation for the term “total weight” used in equation (1). Is the weight of “single cabbage head”?  Please see the name of the same parameter in Line 322 and in the line 323 – there is “average weight”. Further, please see Table 3. There is a column with the name “Weight”. Which weigh is shown here? “Total” or "single cabbage head or "average weight"? So, please, name the parameter by the same way (in equation 1, in the text and in the Table 3).

Please, remove the several repetitions of the abbreviation explanation for ECEC from the text: first one is in line 193 -Effective Cation Exchange Capacity (ECEC) – it is OK,  but the second one is in lines 200-201, the third one – in line 394; all next – in lines 407, 410, 571.

Please, check the using of superscripts for ions Ca2+, Na+, K+ in lines 573, 574, 577.

Author Response

I have minor comments to the significantly improved text of the authors:

Line 79:  In the phrase “Similarly, , low” one comma is superfluous.

It was corrected

All names of the authors of the references mentioned in the article (Line92: Kottegoda et al. [34]; Line 97: Al-Uthery and Al-Shami [35]; Line 99: Maghsoodi et al. [27]; Line 101: Sharma et al. [33]; Line 104: Dong et al. [36] ; Line 106: . Sheoran et al. [32]; Line 108: Shalan [37]  ) should be removed, and only the numbers of the references should be kept in the main text. This rule is common and recommended for the authors published in the MDPI Journals. Please, see the recommendations in the "word template".

Thank you very much, all of them were corrected.

Similar but not the same situation is in Table 7: Please remove the names of investigators from the column 1, and add only numbers of corresponding references in square brackets to the Table. Now, the numbers of references are absent in the Table at all.  Please, name the column “Reference” instead of “Study” in the Table.

Done

Line 293: Please add explanation for the term “total weight” used in equation (1). Is the weight of “single cabbage head”?  Please see the name of the same parameter in Line 322 and in the line 323 – there is “average weight”. Further, please see Table 3. There is a column with the name “Weight”. Which weigh is shown here? “Total” or "single cabbage head or "average weight"? So, please, name the parameter by the same way (in equation 1, in the text and in the Table 3).

Thank you very much for your advice. The terms were unified as “average weight”.

Please, remove the several repetitions of the abbreviation explanation for ECEC from the text: first one is in line 193 -Effective Cation Exchange Capacity (ECEC) – it is OK,  but the second one is in lines 200-201, the third one – in line 394; all next – in lines 407, 410, 571.

All of them were changed and deleted.

Please, check the using of superscripts for ions Ca2+, Na+, K+ in lines 573, 574, 577.

They were corrected.