Combination of Phytoextraction and Biochar Improves Available Potassium and Alters Microbial Community Structure in Soils

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

 The work presented in this paper deals with the effect of phytoremediation and biochar addition for the remediation of Cd and Pb polluted soils.

 The article is clearly written.  The conclusions are restricted to the only significant results, i.e. the K availability and some bacterial and fungal communities changes.  I fully agree with these conclusions which are well interpreted from the observed results.  Even if the conclusions are somehow expected when we consider the K availability of the biochar by comparison to the soil (Table 1).

 But the aim of the study is not clear for me.  From the introduction of this article we expect that the fate of the heavy metals Cd and Pb will be followed in some way.  Indeed in the materials and methods section, the experimental design involves the adding of Pb(NO₃)₂ and Cd(NO₃)₂ at a concentration 5 times higher than the background level of the soil.  But in the rest of the study no attempt is made to follow the availability of these heavy metals in the soil according to the biochar addition or the use of plants for phytoremediation.  It should be a key factor of this study.

 In my opinion this question of Pb et Cd availability should be addressed in this article to deserve publication.

 

Comments on the Quality of English Language

No comment

Author Response

Thank you for the extremely helpful and detailed comments provided for our paper. According to your advice, some of your questions were answered below.

I agree with your point of view. This study was comprehensive. It was done with a focus on the effects of biochar addition and phytoremediation on the biochemical characteristics of the soil on the one hand, and on the remediation of heavy metals in the soil by the method on the other, which just didn't come through in this article. And we will further study its effect on heavy metals.

Reviewer 2 Report

Comments and Suggestions for Authors

This paper addresses the complex interactions of plant-based remediation and their effects on microbial communities. Plant nutrient levels were affected as was microbial abundance. I have no specific suggestions for improvements.

Author Response

Thank you for your recognition of our paper.

Reviewer 3 Report

Comments and Suggestions for Authors

General comments

The article is interesting, however there are some points that need to be improved, especially the materials and methods and discussion part.

 

Specific comments

Materials and Methods:

Lines 95-96:  The coordinates should be from the centre of the experimental plot. They must be expressed in degrees minutes and seconds.

Table 1.

The soil analysis methods used should be described. Not only as a comment to table 1.

Results

Figure 1.

The colours should be substituted by different types of patterns. The colours used are misleading. Why have colours not been used as in figure 2?

Discussion:

Authors should strive to better explain what their research contributes to the state of the science. Their explanation needs to be improved. They should use more references from international publications to improve the discussion part.

 

Author Response

Thank you for the extremely helpful and detailed comments provided for our paper. According to your advice, we amended the relevant part in the manuscript and marked it yellow.

1. We have modified the format of coordinates marked with yellow. The test methods used in Table 1 are described uniformly in "2.3. Determination of soil chemical properties".
2. Regarding the colour of Figure 1, Figures 2, 3 and 4 are all rich in colour as they make a distinction between fungi and bacteria. Figure 1 is a differentiation of treatment, if we choose one of the colours in Figure 2, it is easy to cause misunderstandings.
3. We have added relevant international literature to the discussion part of the article and marked it with yellow.

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

I accept the explanation for the lack of monitoring of the heavy metals biodisponibility but the upcoming publication of the companion paper dedicated to this part of the study should be explicitly indicated in this article.

Comments on the Quality of English Language

I understand without problem the paper.

Author Response

Thank you for your comments. According to your advice, we amended the relevant part in the manuscript and marked it green. We have added references to previous research results in the INTRODUCTION section - Partial remediation results of heavy metals Pb and Cd by this combined remediation method. We hope the above changes are what you want to see.

Reviewer 3 Report

Comments and Suggestions for Authors

The proposed changes have been made.

Author Response

Thank you for your recognition of our paper.