Anaerobic Digestion Reduces Seed Germination and Viability of Six Plant Species from the Upper Nile Valley, Egypt

Round 1

Reviewer 1 Report

I have specific comments that need to be clarified and /or improved:

General Comments:  The authors use the word weed to describe certain crops (wheat and shore gum).  They also mentioned the presence of up to 470 weed species in Egypt (line 123). I would use the term undesirable crop species instead.  The study addresses a small number of such species and the outcome with respect to AD is well established (lines 97, 98). True weeds are probably harder to kill/suppress via AD than crops.

Table 1 - the AD temperature shmpiuld be included

Line 56 I would use the terms inorganic substitute fertiliser. 

Line 163 rewrite as it is not clear

Lines 165-171  these are crops not weeds. Should use the term undesirable crops instead.

Line 192 55oC is mentioned even though the study is mesophilic. Explain or change!

Line 201 Mention the volume of the culture bottles

Line 202 Seeds are presumably in bags. Are the seeds exposed to the liquid in the digester or just the temperature. Please explain.

Line 277 Reference is made to Table 1 connected to the results of this study, but Table 1 is someone else's study. Please correct accordingly statement.

Table 2  Needs further explanation - it is not clear at all/actually is confusing the way it is presented.

Lines 366 to 391 Covers results from other studies that essentially confirm what the present paper has found. In fact, it makes this paper almost superfluous, because it doesn't show anything new or unusual.

General comment about the Discussion section : it can be substantially reduced in size, because 2/3rs of it cover the results of other studies vs. the one reported in this paper.

Lines 441-455 If the seeds are contained in sealed bags, how can they be exposed to the pH, water, etc. in the digester?  Please explain. Also see earlier comment on Line 203. 

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

The paper describes a study of practical utility which also makes contributions of basic nature. The study has been logically conceived, meticulously planned, and skillfully executed. The data has been subjected to proper statistical analysis, and then presented systematically and compactly. In view of this the paper appears fit to be accepted. However major revision is needed as explained below.

1. The language is, by-and-large, lucid, compact and clear. But mistakes have crept in. They are exemplified in the corrections shown in pages 1 and 2 of the MS (please see word file uploaded). These corrections are indicative, not exhaustive and authors need to carefully debug the entire MS on the basis of these illustrative examples.

2. Usages like “We visited” (line 166) and “We conducted” (line 189) should be modified to put them in third person.

3. Lines 336-340 and 351-364 of the Discussion section are virtual repeats of portions of the Introduction section. Substantial repetition goes on till Line 391. These portions need to be drastically reworked . Discussion section should, one by one, refer the results of different aspects of the Investigation and then explain the implications of each segment of results in the context of the relevant prior art.

Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Congratulations on the study and the way the paper was presented. 

I have just a few small comments:

- in table 1 please provide an explanation of what a, b, c, d represents 

- I'm sorry but I don't understand what was meant by Tables S1 and Tables S2 (lines 286, 290, 295). In that paragraph, reference is made to figure 2 where we have no S1 or S2. Change that term so that it is as simple and general as possible to understand what you want.  also in figure 2, within each figure you have the notations a, b, c, d, e, f which are not explained (a is specific to the interval ....., b .....). It would also be better if these were changed because when explaining the figures there can be a slight confusion between the notations inside the figures and the numbering of the figures ((a), (b), ...(f)).

- the same observations in figure 3

- after checking the article I opened the additional file where are the 3 tables S1, S2 and S3.  I advise you to include these tables in the paper, as they are part of the statistical analysis of your data, but please redo the notations (table numbering).

Author Response

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Author Response File: Author Response.pdf