The Effects of Soil Application of Digestate Enriched with P, K, Mg and B on Yield and Processing Value of Sugar Beets

Round 1

Reviewer 1 Report

- either use elmental names (e.g. P, K, Mg...) or full name phosphorus, ... it does not really matter how you do it, but it should be uniform
- plant names should be in italics...
- 30,000 Mg - why not use kg? 

- Introduction is alright with me but could be more concise

- Table 2: what about uranium? there is an interesting paper of another researcher from Poland working on uranium in mineral fertilizers (https://doi.org/10.1016/j.resourpol.2019.02.012). Is uranium an issue?

- Figure 1 and 2 increase the font size in the figures - same with all the other figures, maybe I am getting old, but I can really not read this well...
also consider using different colors for the figures

- I am missing a conclusions chapter

Author Response

Dear Reviewer, Thank you for your remarks. Figures were corrected according to your suggestion. As far as uranium is concerned we have not analytical equipment available to determine its content. I fully agree that in case of processing some phosphates containing rock radioactivity background in agricultural soils can be increased. Conclusion section was marked. 

Reviewer 2 Report

The article “The effects of soil application of digestate enriched with P, K, Mg and B on yield and processing value of sugar beets” reports the results of an investigation aimed at assessing the effects of digestate application (either raw or enriched) to the soil for the cultivation of sugar beets. The article reports novel content and can be in the interest of Fermentation readers; however, it needs to be improved to reach an acceptable standard for publication. English language is not good at present. I consequently recommend a major revision that should cover the following points:

1. Introduction: beside mentioning the positive aspects, the issues related to heavy metal, pathogens and micropollutants present in digestate could be mentioned as factors that are limiting soil application of anaerobic digestate, considering the strict legislation limits that apply in Europe (e.g., see 10.1007/s13593-013-0196-z, 10.31025/2611-4135/2020.13993).
2. Line 134-135: the specific amount of all fertilizers needed for sugar beef cultivation should be mentioned, beside nitrogen (i.e., kg P/ha, kg K/ha, kg Mg/ha etc.) to give a better overview to the reader.
3. Line 145: normally P≤05 is used to assess significance of differences; please check and correct.
4. Results and discussion: the titles of subsections are too long (especially considering sections 3.2 and 3.3).
5. Figures: consider increasing the size of the characters, as they are too small. The quality of the figures is generally poor.
6. Fig. 7: shouldn’t the first bar be “required maximum value”?
7. Results and discussion: no discussion is made with existing literature; the authors should compare the present results with meaningful literature studies published in the past (especially in the last 10 years).
8. Results and discussion: what are the perspectives of this study? The authors should pave the way for future work in the field (e.g., longer tests, economic analysis concerning different fertilizer solutions, analysis of environmental impacts).
9. English language has to be significantly improved; native speaker revision would be beneficial to this purpose.
10. References: most of the cited papers are from Poland and several self-citations are present; please improve the bibliography in order to make it more internationally sound.

Author Response

Dear Reviewer, Thank you for your review and your remarks and suggestions. Please find my answers to points you made below.

1. Introduction Please note that publication Nkoa (2014) is cited three times in the text. In lines 45-47 literature suggested by you (Khakbaz et al. 2020) is cited.
2. Added in lines 124-127 nutrients recommended rates.
3. Clerical error was corrected – you are absolutely right it should stand P£05
4. Titles were modified.
5. Figures were edited.
6. Text was corrected.
7. There is a problem with finding literature about effects of soil amendment on quality of sugar beets as a stock material for processing. Environmental safety of digestate application was underlined.
8. Literature was added and in section Results and Discussion some sentences have been added.
9. English language was checked by native English speaker.
10. References were edited only one Polish publication was left some self-citations were left because methodology was in details described earlier. Four new articles (published in 2020 and 2021) were added.

Round 2

Reviewer 1 Report

Thank you - this is fine with me now

Reviewer 2 Report

The authors answered in a good way to reviewer comments. I consequently recommend manuscript acceptance.