Nutrient Release and Ammonia Volatilization from Biochar-Blended Fertilizer with and without Densification

Round 1

Reviewer 1 Report

In this study, the authors investigated the effects of blending fertilizer with biochar on the nutrient release and ammonia volatilization from the biochar-blended fertilizer with and without densification. This manuscript is generally well written and provides information that may be interesting to the readership of Agronomy. 

1. The objectives of this study need to be better justified with describing the methodologies used in this study.
2. Line 90 - Heating at 340 degree Celsius for 2 hours may not be sufficient to convert biomass into char.  Please provide an experimental evidence to support the formation of char in the product. 
3. Lines 95, 99 and 101 - Please explain why these specific ratios were used in this study. 
4. Line 128 - Eliminate Equation 1 because it is too basic to describe.
5. Line 133 - Explain why this specific soil was selected and used in this study.  
6. Please pay attentions to significant figures in the results. They need to match the analytical sensitivity of the methods used in this work. For example, the resolution of FTIR is generally several wavenumbers, so it is inappropriate to report the band positions to two decimal places. 
7. All the assignments of the FTIR bands require the supports from appropriate references. 
8. Plot the FTIR spectra in absorbance scale rather than transmission scale because only absorbance can be used in quantitative comparison.
9. All the results of nutrient releases need to be normalized with the total nutrient contents of the materials. Otherwise, wrong conclusions could be obtained in terms of the nutrient releasing rates. 
10. Line 387 - This statement may be incorrect, depending on which type of N fertilizers is mentioned here. For example, nitrate fertilizer will not undergo hydrolysis at high pHs. 
11. Line 401 - This statement is contradictory with that in Line 387. 
12. Line 418 - There is no experimental evidence to support the binding of nutrients to aromatic structure in biochar. 

Author Response

The authors would like to thank the reviewer for his/her valuable time and comments. We have addressed the questions/comments to the manuscript accordingly. Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Dear Authors,

Your manuscript is innovative, interesting and important because developing fertilizers with minimal nutrient loss while providing adequate nutrition for plant growth is of great importance for the sustainable development of agronomy and the environment. The laboratory incubation experiment not correspond to real conditions in the field. I agree with the authors that a long-term field study should be conducted to confirm the obtained results. I suggest extending the research to other soil types. The laboratory incubation experiment not correspond to real conditions in the field. I agree with You that a long-term field study should be conducted to confirm the obtained results. I suggest extending the research to other soil types.

The present paper is prepared in the usual manner for scientific work, both the division into chapters, the selection of references and collected results in the form of figures. However, the MS needs some improvements.

Lines 309-323: no reference to literature;

Line 344: instead of "(Chien et al., 2011)" it should be [25];

Lines 357-360: no reference to literature;

In my opinion, the manuscript is clearly written, but I don't feel qualified to judge about the English language and style.

The subject of the manuscript is consistent with the scope of the "Agronomy". 

Sincerely yours

Reviewer

Author Response

The authors would like to thank the reviewer for his/her valuable time and comments. We have addressed the questions/comments to the manuscript accordingly. Please see the attachment. 

Author Response File: Author Response.pdf

Reviewer 3 Report

Dear Authors,

change the title, for more precise one, adding the study area. 

Best regards,

Reviewer

 

 

 

Author Response

The authors would like to thank the reviewer for his/her valuable time and comments. We have addressed the comment to the manuscript accordingly.

The details are listed below.

General Comment

change the title, for more precise one, adding the study area. 

Response: The title has been changed to “Nutrient release and ammonia volatilization from biochar-blended fertilizer with and without densification.”

Round 2

Reviewer 1 Report

1. The authors need to pay attentions to the significant digits of the data. They need to match the analytical accuracy and precision of the methods used in this study. In particular, it is very inappropriate to report the FTIR bands to the second decimal points.
2. It is sometimes difficult to assign IR bands of materials with a complex composition, such as biochar, because there may be several options for assigning each band. Thus, the band assignment has to be conducted in a systematic way with a good reference of the group frequencies. It is also better to assign the IR bands with one source of the group frequencies rather than assign each IR band with different references. For the guidelines of IR band assignment, the authors could refer to "J. Coates (2006) Interpretation of infrared spectra, a practical approach. DOI: 10.1002/9780470027318.a5606"

Author Response

We highly appreciate the detailed valuable comments of reviewer on our manuscript. The suggestions and comments are helpful for us and we have incorporated them into the revised paper to improve the quality of paper. We have addressed the comments to the manuscript accordingly. Please see the attachment.

Author Response File: Author Response.pdf