Environmental Effects of Using Ammonium Sulfate from Animal Manure Scrubbing Technology as Fertilizer
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsGood study, these are my few comments,
What is the rationale for comparing maize and grass, can you provide substantial justification, maize should have been compared with either another breed of maize or other annual crop, and grass should have been compared with grass?
Why will a field need ammonium nitrate, this should be well justified,
Heating the digester to what temperature line 31
Please indicate the value of pH, don't just say high or low e.g., line (32,57). Include reference in Line 57.
Line 106, how did you achieved 60% water holding capacity, how do you ensure it is consistent.
Line 165, the word mistake is too vague, can it be further described.
Figure 1, Dry in the vertical left axis should start with a capital ‘D”
In Figures 1 and 2, “Maize” and “Grass” on the vertical right axis should be pointing upward and not downward
You suspected leaching for Sulphur, wont there be any leaching for nitrogen also
Author Response
dear reviewer,
thank you very much for your detailed review, and friendly words. I will try to answer your comments below.
-What is the rationale for comparing maize and grass, can you provide substantial justification, maize should have been compared with either another breed of maize or other annual crop, and grass should have been compared with grass?
The goal was to test the liquid ammonium sulfate for relevant crops, not specifically to compare crops. So grass and maize are the most important crops for livestock farmers in the Netherlands, that currently produce ammonium sulfate.
To improve the manuscript I have added a sentence behind hypothese 1: "Maize and grass are the most relevant crops for livestock farmers in the Netherlands."
-Why will a field need ammonium nitrate, this should be well justified.
We use the fertilisation advice for the N application, and we used ammoniumnitrate as a reference fertilizer, as this is the most used fertiliser in the NW Europe.
To improve the manuscript I have added a sentence in the last part of chapter 3.1 : "We use CAN as a reference fertilizer as this is the most used N fertiliser in NW Europe."
-Heating the digester to what temperature line 31
This is mentioned in the text: "the temperature of the liquid digestate in the N-stripper (45 °C) in order to promote NH3 transfer to the air"
-Please indicate the value of pH, don't just say high or low e.g., line (32,57). Include reference in Line 57.
Thank you, I have added pH>7 and pH<7, including the reference to the EEA handbook. I have included the website to the reference.
https://www.eea.europa.eu/publications/emep-eea-guidebook-2023/part-b-sectoral-guidance-chapters/3-agriculture/3-d-agricultural-soils-2023/view
-Line 106, how did you achieved 60% water holding capacity, how do you ensure it is consistent. Thank you for the question. We used a balance to daily weight every pot.
I have improved the text : "Soils were established and maintained gravimetrically at 60% water holding capacity by daily watering".
-Line 165, the word mistake is too vague, can it be further described.
The assistent applied the wrong amounts the fertilizers to the plots, and the amounts were not written down.
I have added the following text: (wrong fertilization of treatments).
-Figure 1, Dry in the vertical left axis should start with a capital ‘D”
-In Figures 1 and 2, “Maize” and “Grass” on the vertical right axis should be pointing upward and not downward.
Both aspects have been adjusted.
-You suspected leaching for Sulphur, wont there be any leaching for nitrogen also.
Thank you for the question. The amount of nitrogen was as advised, while the amount of S was much higher (the consequence of using only ammonium sulfate as N source). So a large part of the N from the fertiliser will be taken up by the crop, while a large amount of S is not taken up by the crop. Therefore this surplus will leach. In the text: "...excess of S can leach....".
Thank you again for the comments, and questions to improve the text.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsPlease, refer to individual comments and corrections included in the manuscript file.
Comments for author File: Comments.pdf
While it the manuscript is fully comprehensible, it should be reviewed once more to remove sloppy and redundant wording.
Author Response
dear reviewer,
thank you for the review. In total 31 comments and suggestions were given. Also the reviewer states ""While it the manuscript is fully comprehensible, it should be reviewed once more to remove sloppy and redundant wording". I thank you for your helpful comments, and I have asked an English-speaking person to improve the manuscript. The number of language improvements are large, and can be found in the manuscript (we used track changes).
I thank you very much for the improvements. All comments have been treated in the new submission using track changes. All suggestions were exactly used. In other cases I here refer to each individual comment from your pdf for which a certain choice was made in wording.
page2 17 comments, all have been replaced by the given suggestions.
page3, 1 comment . I have removed redundant wording, and changed the text to: "The samples were analyzed by LUFA Nord West Hameln Germany using methods given in Table A2."
page 4, 3 comments, all have been replaced by the given suggestions.
page 11, 1 comment. "You mean that the achievable measuring accuracy was not sufficient to distinguish between the overall low emissions, in all cases?". Yes, exactly. I have improved the text.
Original text: "The greenhouse experiment provided no evidence for significant differences in NH3, N2O, or CH4 emissions caused by fertilizer type. However, this may have been caused by the very low amount of emissions measured overall".
New text: "The greenhouse experiment provided no evidence for significant differences in NH3, N2O, or CH4 emissions caused by fertilizer type because in all cases the emissions were lower than the achievable measuring accuracy".
page 19, 2 comments.
The reviewer states "Legislative documents need not be included in the list of references, but simply cited within the text". I would normally agree with the reviewer on this point, but this is a draft text from the EU which cannot be found very easily.
The comment of the reviewer: "Document is difficult to find. Please, state the direct link or provide guidance how to find the specific document!" Link has been added.
page 20, 7 comments. Thank you for the detailed improvements. All have been replaced by the given suggestions
Author Response File: Author Response.pdf
