Nitrogen Fractions in Soil Fertilized with Waste Organic Materials

Round 1

Reviewer 1 Report

This experiment designed carefully, and Nitrogen fractions analyzed very detailed. Data and conclusions are solid. My key concerns are that: 1) the soil samplings were after harvest, which were influenced heavily by crop productivity, adding the data of biomass or grain yield would be useful; 2) all the organic materials would be beneficial to increase soil organic C content, leading to the increase in N contents, but the key factor for the organic materials was not N contents but the toxic properties, this paper did not mentioned that.

The research objective is easy to understand, you need not say so much in the Introduction part.

Table 2 & 3 need data besides the letters of significant differences.

Author Response

Thank you very much for reviewing our work.

1. Organic materials were applied to the soil for a period of 12 years. The results presented in the paper concern the long-term impact of fertilizers and waste on the content of various nitrogen fractions in the soil. In our opinion, giving the last year's yields would not be the best solution, because sparingly soluble N compounds are not a short-term effect.
2. In line with the remark, the paper contains data on the content of heavy metals in all materials used for soil fertilization (tab. 1).
3. The introduction has been changed a bit.
4. Note 4. Table 2 & 3 need data besides the letters of significant differences. In our opinion, it is not necessary to include data about significant differences. The letters inform about homogeneous groups and in our opinion it should stay that way.

Best wishes

Reviewer 2 Report

The suggestions were shown as follows:

1. There are too many long sentences and the overall English expression needs to be strengthened.
2. The implications of some abbreviations in the abstract were not provided or mutually corresponding.
3. The descriptions in the Introduction were lack of research innovation and contents.
4. The format of references should be modified by referring to the latest articles in the Agronomy.
5. The error bar was needed in the Fig. 3.
6. In order to make the attached drawing structure more beautiful, probably the features of tags in all figures should be improved.

Author Response

Thank you very much for reviewing our work.

1. The text of the thesis has been verified and corrected for the English language.
2. One abbreviation (CMGW) was incorrectly given in the summary. This bug has been fixed and it is now CUMW.
3. It is difficult to find published research data on the effects of many years of influence of various organic substances on soil properties, and even more so on the content of various forms of nitrogen in it. Our research in this regard should be considered innovative.
4. W rękopisie odwołujemy się do 5 ostatnich artykułów w Agronomii (wpisy 15, 16, 17, 22 i 23).
5. Na 3 przedstawiono dane dotyczące udziału 3 frakcji azotu (N-nh. - nie hydrolizujących; Nh. - hydrolizujących (łatwo + trudno); N-min. - N-mineralnych) w całkowitej zawartości N w glebie. Dane te nie zostały poddane analizie statystycznej, naszym celem było jedynie zobrazowanie różnic.
6. Informujemy, że poprawiono jakość danych.

Wszystkiego najlepszego

Reviewer 3 Report

Dear authors,

I have finished the revision of the manuscript entitled “Nitrogen fractions in soil fertilized with waste organic materials” by Wierzbowska et al. In this manuscript the authors evaluated the effect of sewage sludge and municipal waste on the content of various forms of nitrogen in the soil. This subject fits with Agronomy scope and the main strength of this study in the length. Eleven years.

The justification of the study was well done. The methods used were adequately described with sufficient detail to repeat the research. The authors used relevant literature to interpretate the data. The quality of figures is not good and can easily fixed.

I think the manuscript can be accepted for publication.

Author Response

Thank you very much for reviewing our work.

Please be informed that the quality of the drawings has been improved.

Best wishes.

Reviewer 4 Report

• On the page number 6 Authors says: " Significantly the lowest content of this nitrogen form(N-NO3 ) was in the soil fertilized once in a crop rotation with 10 t d.m./ha CMGW ". See on the figure 2 - the lowest content is in twice in a crop rotation with a dose of 5 t d.m./ha
• References numbers 16, 23, 25, 27, 28, 29, 30, 46 and 53 must be tranlated on the English language.
• Methods of Egner-Riehm and Schachtsachabel should be placed in the references

Author Response

Thank you very much for reviewing our work.

Regarding the comment on the text on page 6. It is: The content of N-NO₃ varied from 2.22 to 4.12 mg N kg^-1 of soil (Fig. 2). Significantly the lowest content of this nitrogen form was in the soil fertilized once in a crop rotation with 10 t d.m. ha^-1 CMGW. It was by 27% less than in the control soil and by 21% less than in the soil fertilized with NPK.

This is our mistake and it has been corrected as suggested by the reviewer, thank you. Now it is like this: The content of N-NO₃ varied from 2.22 to 4.12 mg N kg^-1 of soil (Fig. 2). Significantly the lowest content of this nitrogen form was in the soil fertilized twice in a crop rotation with 5 t d.m. ha^-1 of CMGW. It was by 29% less than in the control soil and by 21% less than in the soil fertilized with NPK.

Regarding bibliography note – corrections were made.

Data on the Egner-Riechm and Schachtschabel methods are included in the bibliography.

Best wishes.

Round 2

Reviewer 1 Report

I think this paper is acceptable for publication.  

Author Response

Thank you very much for your opinion about our paper.

Reviewer 2 Report

In this work, the effect of sewage sludge and composts produced from sewage sludge and municipal waste on the content of various forms of nitrogen in soil has been explored. The experimental data of the article is relatively detailed, the analysis and discussion of the results are relatively sufficient, and the research results have certain significance and reference value. However, there are several problems: (1) Some abbreviations in the abstract did not give the corresponding full names. (2) Key words are too few, not comprehensive enough, can be increased appropriately. (3) The format of the diagrams is not standardized enough, and the diagrams should be closed. (4) While investigating nitrogen fractions in soil fertilized with waste organic materials, should it be more important to investigate whether the pollutants in the waste will migrate or accumulate in the soil?

Author Response

Thank you very much for such a precise work of the reviewer. This actually helps us to improve our paper.

Point 1: Some abbreviations in the abstract did not give the corresponding full names.

Response 1. Fixed, all full names are now assigned to abbreviations.

Point 2: Key words are too few, not comprehensive enough, can be increased appropriately.

Response 2. We have increased the number of keywords by: NPK, FYM and composts from different waste. Now it's like this: NPK, FYM, sewage sludge; composts from different waste; content of N fractions in soil.

Point 3: The format of the diagrams is not standardized enough, and the diagrams should be closed.

Response 3. We improved the diagrams and now they're all closed - the same style is kept throughout the paper.

Point 4: While investigating nitrogen fractions in soil fertilized with waste organic materials, should it be more important to investigate whether the pollutants in the waste will migrate or accumulate in the soil?

Response 4. In our opinion, it is extremely important to study the migration of pollutants in the soil. We devoted our work on "Nitrogen fractions in soil fertilized with waste organic materials" to nitrogen compounds in the soil. Prblem is important from both its agricultural  and environmental aspects. Non-hydrolysable nitrogen compounds remain in the soil and, in a way, testify to its fertility. On the other hand, the nitrogen from hydrolysable nitrogen compounds can be used quite easily by plants, but it can be washed away.

We would also like to inform you that we have already published studies on the content of heavy metals in the soil and their leaching.

1. Wierzbowska, J., Kovačik, P., Sienkiewicz, S. Krzebietke S. Bowszys T. 2018. Determination of heavy metals and their availability to plants in soil fertilized with different waste substances. Environ Monit Assess 190, 567  https://doi.org/10.1007/s10661-018-6941-7
2. Wierzbowska, J., Sienkiewicz, S., Krzebietke, S. Bowszys T. 2016. Heavy Metals in Water Percolating Through Soil Fertilized with Biodegradable Waste Materials. Water Air Soil Pollut 227, 456 (2016). https://doi.org/10.1007/s11270-016-3147-x

3. Wierzbowska, J., Sienkiewicz, S., Sternik, P., & Bowszys, T. 2016. Content of macroelements in leachate from soils fertilized with organic materials. Fresenius Environmental Bulletin, 25, 6132–6138.
4. Bowszys, T., Wierzbowska, J., Sternik, P., Busse, M. K. 2015. Effect of the application of sewage sludge compost on the content and leaching of zinc and copper from soils under agricultural use. Journal of Ecological Engineering, 16(1), 1-7. https://doi.org/10.12911/22998993/580

Thanks a lot  once again

Author Response File: Author Response.docx