Biochar–Nitrogen Composites: Synthesis, Properties, and Use as Fertilizer for Maize
Round 1
Reviewer 1 Report
Comments and Suggestions for Authors
The main goal of the study is to synthesize biochar-N composites and showed that Maize biomass was lower for plants nourished with raw biochars without mineral N doping, indicating that the availability of N from the carbonized matrices is reduced, and N is not released within the required timeframe for maize plants. The study delves into a topic of great relevance for both theoretical understanding and practical applications. Nonetheless, there are certain areas that require revision and clarification.
Comments for author File: 
Comments.pdf
Comments on the Quality of English Language
Moderate editing of English language required
Author Response
Dear Reviewer.
We would like to thank your for many constructive suggestions listed in your report. We have worked diligently to improve the manuscript structure and edition.
We have worked to answer the questions raised in your report as follows:
Question:
General comments:
1. The authors should avoid using pronouns such as “we”, “our” and “us” in the whole text (e.g., line 15).
2. The article needs thorough revision to improve the language, sentence construction, and easy comprehension.
Answer: the manuscript was revised to avoid the use of the pronouns mentioned. The whole manuscript was revised regarding English Grammar and style.
Question:Abstract:
The Abstract should indicate the originality/value in terms of its contribution to the international literature.
Answer: the abstract was revised and a new topic (statement of novelty) was added in the manuscript body to address the issue raise related to the originality of the study.
Question:
Introduction:
4. The significance of the study should be added in the Introduction.
5. How the proposed study addresses the existing gaps?
6. Why is it timeliness to explore such a study?
7. What makes this study different from other studies in the world?
8. What are the research question?
Answer: a new paragraph was inserted in the introduction section, before the hypothesis, to answer the relevant issues raised.
Question: Page 1, lines 41-43: Consider revising this sentence “The challenge of producing more food world wide is increasingly difficult to attain, given a scenario of intensified climate change and scarce, expensive inputs, such as nitrogenous fertilizers, extensively imported by Brazil from other countries.” for better flow.
Answer: the phrase was revised and its English structure was improved.
Question: Clarify the transition between the general introduction and the specific focus on nitrogen fertilizers and biochar-based composites.
Answer: yes, perfect, the whole introduction was revised to clarify the points raised and to link the paragraphs. Please, check the new edition of the introduction section.
Question: Check for consistency in the use of abbreviations and acronyms (e.g., “N” for nitrogen).
Answer: thanks for reminding us about this error. The whole manuscript was revised.
Question: Consider rephrasing or adding a connecting sentence to better link the last paragraph to the objectives of the study.
Answer: a new paragraph was added to the introduction in order to meet and answer the point raised. See the new text added before the hypotheses and study aims.
Question: A concise summary or roadmap of the subsequent sections could be beneficial to guide the reader through the study.
Answer: The introduction was revised, a new paragraph was added to this section and the statement novelty was inserted in the body of the manuscript. It is our belief that actions could create a roadmap for the AppliedChem's readers.
Question:
Materials and Methods:
14. Include a brief rationale for choosing chicken manure and leguminous cake as feedstocks, as well as the reason for choosing the synthetic mineral fertilizers (AS, DAP, Urea).
Answer: the rationale was inserted in this section for the issues raised.
15. Provide more information on the carbonates added to the soil before maize cultivation, including the quantity and type used.
Answer: ok, the carbonate reagents, proportions and mass added per kg soil was mentioned in this part of M&M.
16. Clarify the reasoning behind the pH adjustment of the feedstocks using sulfuric and phosphoric acids, and why this range (pH 5-6) was targeted.
Answer: yes, we provided a justification for choosing the pH range and acids. Please, check this section in the M&M.
17. Ensure consistency in the spelling of “biochar” (biochar/biochars).
Answer: the text was revised.
18. In the equation for biochar yield, correct the typo (“feedstcoks” to “feedstocks”).
19. Page 6, line 237: Clarify the sentence “The FTIR spectra and their bands were interpreted based on the libraries available elsewhere [29-35].”
Answer: the FTIR-ATR spectra and their respective organic and inorganic functional groups and bands were interpreted based in papers already published and related with the understanding of spectral signature of biochar, biochar-based fertilizers and composites.
Question:
Results and Discussion:
20. Overall, this section is well-written and provides a detailed account of the experimental procedures and results; however, the results and discussions could be separated.
Answer: we agree with your suggestions. Unfortunately, we do not have time to separate from the discussion. We edited again the whole section. If this new version of the manuscript is not suitable to be published, it is our intention to revise the text again to find the right and precise format.
21. In the Results section, focus only on the findings of the study.
Answer: Yes, the section was revised with this purpose and the conclusions were re-written.
22. In the Discussion: a) state the main results of the study (do not repeat the inputs of the results section); b) compare and interpret these results in detail with the findings of recent studies; and c) at the end of this section, add the main limitations of the study.
Answer: We have highlighted the limitations and the novelty and importance to perform this kind of research in Brazil. The issues raises are relevant and we payed attention to them in this new version of the manuscript.
23. Please make sure all tables and figures have been cited in the main text.
Answer: thanks for the suggestions. Tables and figures were edited and carefully cited in the body of manuscript.
Question:
Conclusion:
24. In the Conclusion, the focus should be on restating the main results and demonstrating how the research questions have been thoroughly examined and explained.
Answer: the conclusions were again edited and the min finding of the study are listed in this section.
25. And finally, add the novelty of your study, and also, the theoretical and practical implications of this study in one paragraph.
Answer: the novelty and other important results reported in this study was revised and a new section was inserted in the body of the manuscript, i.e., please, check the statement of novelty, which is inserted after the abstract.
Reviewer 2 Report
Comments and Suggestions for Authors
Dear Authors,
It would be good to investigate in the future how the different variants of fertilisation affect the microorganisms in the soil (microbiome). On the one hand, it is known that the long-term use of mineral fertilisers reduces the biodiversity of the microbiome. Even the application of liquid manure to a meadow leads first to the death of the fungi and then of all the plants that form symbiotic relationships with them. The addition of organic material, on the other hand, improves the bacterial and mycobiome both qualitatively and quantitatively. It is therefore worth recognising how the addition of biochar-nitrogen composites affects not only the physico-chemical properties of the soil, but also its biological life. After all, many bacteria support the growth and development of plants, provided they find the right living conditions (food), and we are not talking about individual species here, but a large number of them. They dissolve compounds such as phosphorus and make it available to the plants, not to mention the N-binding bacteria from the air. In large-scale agricultural crops such as maize, the biological life of the soil is usually very simplified, so that ever larger quantities of mineral fertiliser have to be applied to keep yields at the same level. It is not clear how much longer this type of agriculture will be possible. I would like the authors to take up this issue and address it in the discussion.
Comments on the Quality of English Language
The English language is not objectionable, the text is comprehensible and requires little intervention.
Author Response
Question:
It would be good to investigate in the future how the different variants of fertilisation affect the microorganisms in the soil (microbiome). On the one hand, it is known that the long-term use of mineral fertilisers reduces the biodiversity of the microbiome. Even the application of liquid manure to a meadow leads first to the death of the fungi and then of all the plants that form symbiotic relationships with them. The addition of organic material, on the other hand, improves the bacterial and mycobiome both qualitatively and quantitatively. It is therefore worth recognising how the addition of biochar-nitrogen composites affects not only the physico-chemical properties of the soil, but also its biological life. After all, many bacteria support the growth and development of plants, provided they find the right living conditions (food), and we are not talking about individual species here, but a large number of them. They dissolve compounds such as phosphorus and make it available to the plants, not to mention the N-binding bacteria from the air. In large-scale agricultural crops such as maize, the biological life of the soil is usually very simplified, so that ever larger quantities of mineral fertiliser have to be applied to keep yields at the same level. It is not clear how much longer this type of agriculture will be possible. I would like the authors to take up this issue and address it in the discussion.
Answer: Thanks for the very constructive comments and suggestions to improve our research. The points raised in your report was answered and a new section was inserted in the body of the manuscript, with new references (highlighted in yellow) and discussion of the important issues raised in your report. Please, check section 3.9 Agronomic and environmental implications.
Reviewer 3 Report
Comments and Suggestions for Authors
In the article presented the process of pyrolisis, which allows by providing thermal reaction of converting different feedstocks into biochair. In case of slow pyrolisis process, we can use low temperature over the longer residence time, but when we have fast pyrolisis it will need use higher temperature over a shorter residence time. The research experiment was carried out in the Laboratory of Soil Organic Matter Studies at Federal University of Lavras in Brasil. For biochar production it was utilized chicken manure and leguminous cake. The soil for maize production was prepared by using carbonates to achieve soil pH value qual 6,0. Please add in Section Conclusions some Sub Sections presenting the most important findings of the study. Such presented material will make article more readible and more clear for the readers. Please add some recent publications concerning biochar production using agricultural wastes and agriculture feedstocks.
Comments on the Quality of English Language
English language is good.
Author Response
Question:
Please add in Section Conclusions some Sub Sections presenting the most important findings of the study. Such presented material will make article more readible and more clear for the readers. Please add some recent publications concerning biochar production using agricultural wastes and agriculture feedstocks.
Answer: many thanks for your positive comments and suggestions. We edited again the conclusions with brand new finding and results reported in this study. We also inserted an new section (3.9 agronomic and environmental implications) to address the questions and issues raised in your report. Please also check the statement of novelty, which is also related to answers for the important points depicted in your report.
Reviewer 4 Report
Comments and Suggestions for Authors
The paper presents an interesting experiment, but it is not written accurately and requires major improvement.
The following aspects need to be improved:
- in the title, I think it would be interesting to introduce the word at the end. ... for maize.
- the abstract is too long, it needs a synthesis.
- to Keywords: the same can be added .... maize
- the introduction is well documented and at the end the research hypothesis and the objectives of the paper are clearly presented.
- to the material and method - what does ... medium texture mean? - defines the textural content (dust, sand, clay), what is the humus content? and what soil classification did you use - including the reference.
- the decimals in table 1 must be separated with a period (not with a comma).
- the references for the methods and formula from subchapter 2.2 ??
- the references for the methods and formulas in the whole chapter 2 are also not written.
- table 2 and in fact all tables and figures must have decimals separated by a point.
- what does PD mean in figure 2?.
- the figures should be in color and accurately.
- you must use the same form of measurement units, you use when like this: g/pot, when g pot-1. The paper has no accuracy.
- like the paper, the references are without any accuracy in writing.
Comments on the Quality of English Language
Minor editing of English language required.
Author Response
Questions:
The following aspects need to be improved:
in the title, I think it would be interesting to introduce the word at the end. ... for maize. Answer: yes, we agree. See the new edited.
- the abstract is too long, it needs a synthesis. Answer: yes, we agree. The abstract was again editing to be more informative, precise and shorter.
- to Keywords: the same can be added .... maize. Anwer: the word was inserted in the right section.
- the introduction is well documented and at the end the research hypothesis and the objectives of the paper are clearly presented. . Answer: thanks for your positive comments. We inserted a new sub section in this section, which was completely revised.
- to the material and method - what does ... medium texture mean? - defines the textural content (dust, sand, clay), what is the humus content? and what soil classification did you use - including the reference. Answer: yes, the issues raised were cleared and the errors were corrected. See the new edited M&M section.
- the decimals in table 1 must be separated with a period (not with a comma). Answer: the table was revised.
- the references for the methods and formula from subchapter 2.2 ?? Answer: we added the specific reference for the formula.
- the references for the methods and formulas in the whole chapter 2 are also not written. Answer: We revised the whole M&M and new references were added to the manuscript section 2.
- table 2 and in fact all tables and figures must have decimals separated by a point. Anwer: the table was revised.
- what does PD mean in figure 2?. Answer: it was our mistake. The figure was edited to clear the point raised.
- the figures should be in color and accurately. Answer: we agree and all figures were again edited to be precise.
- you must use the same form of measurement units, you use when like this: g/pot, when g pot-1. The paper has no accuracy. Answer: we checked all the text to correct this type of error, including tables and figures.
- like the paper, the references are without any accuracy in writing. Answer: the references were revised, some were suppressed and new references in yellow were inserted in the body of manuscript. Thanks for your diligent revision.
Question: Minor editing of English language required.
Answer: the whole text (manuscript) was revised by a Native English Speaker.
Reviewer 5 Report
Comments and Suggestions for Authors
The authors analyzed six composites of biochar from chicken manure and legumes enriched with three N- sources: ammonium sulfate, diammonium phosphate, and urea in terms of their usefulness as fertilizers for maize. They analysed also pure biochars. The main goal was to check if such approach can improve N-utilization by maize plants. The topic is important in terms of preventing nitrogen losses from the soil and the same way make N-fertilization more efficient and better for environment. The manuscript is well organised and logical. However, there are many editorial errors (both in the text and in terms of figures). I think the manuscript will benefit from English language checking as well. Details below.
Line 48 – replace „our” with for example „in Brasil”– article will be read not ony by Brazilians
Line 85 – lack of space between urea and decrease
Line 102 – „In tits fast version, pyrolysis is suppose to increase the production of bio-oil and gas” – What do you mean by „tits”?
Line 106 „recarding” or „regarding”
Line 143 – unnecessary space before nitrogen, the same in 168, 189 – check please whole manuscript in this matter
Line 180 – what this „Four” here refers to? Maybe it should be „For”
Line 249 – „In total, 10 treatments were evaluated,….” – it will be advisable to list these treatments here or prepare simple Table with basic information about each treatment. It will make manuscript easier to follow for a reader.
I did not find also information how exactly fertilization was performed – by mixing with the soil before sowing? What about urea – it was added three times, so how this applications were performed?
Line 324 – Shouldn’t be titles of the tables above the tables (not below)?
Line 289 – add reference to the table 2, in fact you should add references to all tables and figures in corresponding places the text.
Correct please Figure 3 and 5 in terms of visibility, and mark diagrams with (a) and (b) accordingly in Figure 3
Line 493 „…of in plants….” – correct this - „of” or „in” – not both
Line 513 – composts or composites?
Line 538 – if it is the same, you could not use „than”, you should use „as”
Comments on the Quality of English Language
English needs checking
Author Response
Questions:
The manuscript is well organised and logical. However, there are many editorial errors (both in the text and in terms of figures). I think the manuscript will benefit from English language checking as well. Details below.
Line 48 – replace „our” with for example „in Brasil”– article will be read not only by Brazilians. Answer: the text was revised.
Line 85 – lack of space between urea and decrease. Answer: yes: revised.
Line 102 – „In tits fast version, pyrolysis is suppose to increase the production of bio-oil and gas” – What do you mean by „tits”? Answer: thansk, revised.
Line 106 „recarding” or „regarding”. Answer: this part was revised.
Line 143 – unnecessary space before nitrogen, the same in 168, 189 – check please whole manuscript in this matter. Answer: yes, the whole manuscript was revised.
Line 180 – what this „Four” here refers to? Maybe it should be „For”. Answer: yes, that's right, revised.
Line 249 – „In total, 10 treatments were evaluated,….” – it will be advisable to list these treatments here or prepare simple Table with basic information about each treatment. It will make manuscript easier to follow for a reader.
Answer: we agree, and the text was revised and treatment highlighted in different sections of the manuscript. If necessary, we can edit a new table to describe carefully the tested treatments.
I did not find also information how exactly fertilization was performed – by mixing with the soil before sowing? What about urea – it was added three times, so how this applications were performed?
Answer: yes, the nutrient sources were mixed with whole soil mass (1 kg) before maize sowing. A fraction of urea rate was added to soil in the sowing phase. The urea topdressing fertilization was performed using urea solution, in 2 topdressing applications.
Line 324 – Shouldn’t be titles of the tables above the tables (not below)?
Answer: yes, we agree, and table titles were inserted in the right position. Thanks for the suggestion.
Line 289 – add reference to the table 2, in fact you should add references to all tables and figures in corresponding places the text.
Answer: the text was revised to address the point correctly raised in your report.
Correct please Figure 3 and 5 in terms of visibility, and mark diagrams with (a) and (b) accordingly in Figure 3
Answer: all figures were diligently revised. thanks for the issues raised in your report.
Line 493 „…of in plants….” – correct this - „of” or „in” – not both
Answer: the text was corrected.
Line 513 – composts or composites?
Answer: the right word is composite, revised.
Line 538 – if it is the same, you could not use „than”, you should use „as”
Answer: the text was revised.
Question: English needs checking.
Answer: yes, all text was carefully revised by a native English speaker.
Round 2
Reviewer 4 Report
Comments and Suggestions for Authors
The paper has been improved. I recommend accepting the paper for publication.
