Review Reports

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

General Comments: The results of this experiment are only one way (decreasing phytoavailability of heavy metals and metalloids according to extractability data―DTPA-TRE or other basis). However, one or more years of data is necessary to justify the phytoavailability of heavy metals and metalloids. Again, according to extractability data, year-wise plant concentrations of heavy metals and metalloids have to be presented to justify plant and leachate concentrations and safety levels. In this perspective, a single crop with several soil types was better to investigate for several years, both in lysimeter and field conditions.

 

Specific comments:

Abstract: Only NVS is focused on, but not CFA, which is not consistent with the research title.

1. Materials and methods: Treatment specification, experimental design, and replication number have to be more clearly described.

1.1 Experimentation: It could be written as “Literature review”.

1.3 Mini-lysimeter: Why was it used only for CFA but not NVS, or why wasn’t the 220-L lysimeter used in this case? Again, why was NVS tested in various types of soil in a lysimeter but not CFA?

1.4 220-L lysimeter study: Why not fully factorial, and why wasn’t the application of all the treatments in all the soil types done? Clarification is necessary. Again, why irrigation was done in some cases with tap water and in some cases with WWE is not clearly explained.

1.5 Field studies: Why did some crops receive NVS and CFA but not a crop with both NVS and CFA?

2. Results and Discussion: The heading “2.1” is inconsistent with the subheadings. Where is the biomass data of the subheading “2.2.1 Biomass”? Again, the writing is not consistent with the heading “Biomass”.

Comments for author File: Comments.pdf

Author Response

Thank you. Please see the attachment

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The authors present an agronomic study of the phytoavailability of metals following soil amendments of coal fly ash (CFA) and CFA-treated biosolids. Overall, this contribution is appropriate for Soil Systems. There are, however, a few small things that could be improved. 

1) Figure and table captions could be improved. In their current form, they generally don't help the reader digest the presented data. 

2) More information about the physical & chemical properties of the studied soils would help demonstrate that the study examined a wide range of soil characteristics. This information could be added in Table 2. Potential parameters to add: dominant mineralogy, soil pH, agronomic history, etc. I found myself wondering whether all the soils examined here were calcareous and/or sodic. 

3) If all the studied soils are calcareous/sodic, all soils examined will be alkaline. Assuming this is case, why would an alkaline amendment such as CFA be applied to these soils? The authors partially address in the introduction, but it may help the reader understand the significance of the study if more context was provided about why CFA would be applied to alkaline soils (as opposed to a different amendment). 

Finally, a few small points:

line 259-260: 'pH declines ... 23 mg C / day / lysimeter' -- the quantity and unit described in this sentence are not appropriate for pH

line 298: 'MN' should be replaced with 'Mn'

Author Response

Thank you. Please see the attachment

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

In this study, the authors investigated the role of fly ash and fly ash-treated biosolids in ameliorating the phytoavailability and leachability of heavy metals and metalloids. Overall, the manuscript is well written and of novelty. I think it is suitable for publication in Soil systems. My main comments are as follow:

1. Abstract should be enriched via specific valuable data which pave the way for understanding the study.
2. No line number makes it difficult to give specific comments.
3. There are numerous amendmentsinfluencing phytoavailability and leachability of heavy metals and metalioids in agricultural soils, and especially some microelements decrease Cd uptake and translocation in plants. Therefore, I suggest the authors strength the Introduction and highlight the novelty of this study by referring more papers.
4. Page 15: The beginning of the first paragraph does not connect well with the previous text and seems to be missing some words.

Author Response

Thank you. Please see the attachment

Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors

Phytoavailability and Leachability of Heavy Metals and Metalloids in Agricultural Soils Ameliorated with Coal Fly Ash (CFA) and CFA-Treated Biosolids

The manuscript presents a case study on the application of fly ash and CFA-treated biosolids on agricultural soils. Data were collected from longer-term lysimeter and field studies on heavy metals and metalloids leaching, fate in the soils, and crop uptake and yield, encompassing a wide range of soil characteristics. The data are interesting and the manuscript is in general well written. However, I have several suggestions aiming to improve the manuscript quality:

• The manuscript structure is not totally in agreement with the Instruction for authors’ requirements. Abbreviations should be moved at the end of manuscript (before references section)
• References must be numbered in order of appearance in the text (including citations in tables and legends) and listed individually at the end of the manuscript
• When presenting the aims of the study at the end of Introduction section please mention the thermodynamic studies
• Introduction (line 45) should be numbered. Then, please number the next section (materials and methods) with 2, …
• Introduction. Please add some statements on the metal’s mobility on soil (you can see for reference https://doi.org/10.3390/ma17235977)
• Line 309. Please add the detection limits for elements
• Tables design. Please delete unnecessary lines
• It was used any quality control for the analytical determination
• Please add a subchapter with used chemicals at Experimental section
• References section. Please number the references in order of appearance in the text

Author Response

Thank you. Please see the attachment

Author Response File: Author Response.pdf

Round 2

Reviewer 4 Report

Comments and Suggestions for Authors

The manuscript was improved and can be accepted for publication.