Effects of Soil Amelioration and Vegetation Introduction on the Restoration of Abandoned Coal Mine Spoils in South Korea

Round 1

Reviewer 1 Report

This a great contribution of forest restoration field which benefit for global warming crisis worldwide.

I only have some minor points:

1. Please explain in method why did u choose DCA reveal your ordination plot?
2. Please modify all figure as a color figure especially  figure 6-9 cause your information is great but make it more fancy via color is more better.
3. Table 1 and 3 it is possible to add SD and significant statistics.
4. Conclusion is too long it is possible to make it shorter but concentrate.

Author Response

We revised our manuscript sincerely by accepting reviewer's valuable comments.

Author Response File: Author Response.docx

Reviewer 2 Report

The conclusions must be substantially improved, since it is a generic account of the subject, which does not link the results obtained with the conclusions.
It does not raise conclusions based on the quantitative data obtained, such that it supports the qualitative aspects. The paragraphs are very long and do not specify the relevant aspects and their relationship with the results obtained.
The summary must also be improved, it does not include the results obtained, which should be incorporated.

Author Response

We revised our manuscript sincerely by accepting reviewer's valuable comments.

Author Response File: Author Response.docx

Reviewer 3 Report

The manuscript is about “Effects of soil amelioration and vegetation introduction on restoration of an abandoned coal mine spoils in South Korea”. Hence, this objective suits to the scope of the journal.

The main reasons are in part “inadequate novelty” and “inadequate sampling design” and false projection”. Although more shortcomings exist, the following justification of my recommendation will concentrate on these aspects as they are the more crucial ones.

Novelty: One main part of the manuscript is on amelioration (see title, line 15/16, chapter 3.3 and 4.1, line 622/623). The authors found a positive effect, however this is not new, as they stated themselves (see chapter 4.1, especially line 460-459, 460-464). In addition, soil physical properties were not analyzed, though the authors state to do so (see Tab. 1, Fig. 3).

Inadequate sampling design: The study is restricted on samples from 0-10 soil depths. Roots are also found in deeper soil sections (especially from trees). Thus, the investigated small soil layer does not represent the physic-chemical soil properties for the vegetation.

False projection: It is not clear, if the chosen reference sites can actually serve as reference. The authors did not prove the geological similarity. Did the soils of the reference sites develop from the same parent material than the restored sites? Without this information no comparison is reasonable. From Fig 3 it is more likely that the reference and restoration are not similar, in terms of geology/pedology: Despite lower OM contents in the reference site than in the mine debris (control) the reference exhibited larger CEC, which can solely explained by more CEC derived from mineral compounds, indicating different geological/pedological differences. The manuscript is lacking on detailed geological/pedological investigations. This is also true for the selection of tolerant species: it is stated that similar environmental conditions were the basis, but what kind of environmental parameters? No data supplied. In addition, the investigation design does not allow statements on the effects of the restoration treatment on species composition and diversity because differences may be due to the different restoration durations rather than to the methods (as the authors stated themselves (line 583/584)). Hence, die validity of a couple more parts (in the discussion 4.3, 4.4, 4.5) are questionable.

Inadequately processed discussion: The discussion is overloaded with basic information. The results of the study are inadequately integrated to the state of the art and stay totally separated, just as repetition of the results chapter.  

Apart from that the approach to identify tolerant species on the basis of field survey plus cultivation experiment sounds very promising and should be elaborated. However, the identification parameters should be reassessed for the abandoned sites because they seem to respond to the rural situation rather than to the soil conditions.

Author Response

We revised our manuscript sincerely by accepting reviewer's valuable comments.

Author Response File: Author Response.docx

Round 2

Reviewer 3 Report

Allthough the authors anwered to all my comments, the main shortcomings were not plausible reprocessed. Hence, I maintain my recommendation.

Once again the main points:

• The analyzed 10 cm soil depht does not represent the root living space. Results from this small section canot be tranfered to the whole rooting zone. Soil properties change by dephts. The whole root soil zone must be investigated. In this relation the authors answered, that the restriction is a general method in soil analysis which is definitely not the case.
• The authors assume that the coal mine debris always have the same geological composition. From my point of view this has to be proven. From the data set it can be concluded that geological differences occur between the sites: „I stated in my review: From Fig 3 it is more likely that the reference and restoration are not similar, in terms of geology/pedology: Despite lower OM contents in the reference site than in the mine debris (control) the reference exhibited larger CEC, which can solely explained by more CEC derived from mineral compounds, indicating different geological/pedological differences”. The authors did not touch this aspect at all.
• From soils science view (and related disciplines) I do not agree with the judgment of the authors in respect to content and composition of the discussion I cannot

Small additional hint: pH is not a physic-chemical property, as it gives the hydronium concentration it is solely chmical.

Author Response

Thank you for your considerate comments.

Author Response File: Author Response.pdf