Bamboo Biochar and Zinc Oxide Nanoparticles Improved the Growth of Maize (Zea mays L.) and Decreased Cadmium Uptake in Cd-Contaminated Soil
Round 1
Reviewer 1 Report
The article describes the results of research on the effect of the addition of bamboo biochar and ZnO nanoparticles on the growth and chemical composition of maize as well as selected properties of soil contaminated with cadmium. The research concern to deal with the problem of the production of appropriate quality food and feed in contaminated areas, which is important on a global scale. The obtained results confirm some previous reports on the beneficial effect of biocarbon fertilization and the use of nanoparticles in plant production, indicating the possibility of their effective application also in the cultivation of maize on cadmium contaminated soils. Interesting work, proper methodology (slight additions indicated - details in the comments to the text). It should be emphasized that the study analyzed not only the characteristics and yield of plant biomass, but also the influence of the studied factors on many chemical properties of plants (for example chlorophyll content in leaves, photosynthetic rate, transpiration rate, MDA, activity of several enzymes, Zn and Cd concentrations) and selected soil properties (pH, AB-DTPA extractable Cd). The results are properly described (larger letters in the diagrams would be useful), the conclusions are correct, but it should be remembered that Cd is not the only stress factor in the analyzed soil after fertilization with sewage - the problem may be quite significant salinity or the presence of other, not analyzed contaminants. I suggest minor corrections (details in the form of comments to the text).
Comments for author File: 
Comments.pdf
Author Response
Dear editor and reviewers：
Thank you very much for your letter and the reviewer’s comments concerning our manuscript entitled “Bamboo biochar and zinc oxide nanoparticles improved the growth of maize (Zea mays L.) and decreased cadmium uptake in Cd contaminated soil” (agriculture-1872347). Those comments are all valuable and very helpful for revising and improving our paper. We have carefully revised the manuscript according to each comment referred by the reviewers. In accordance with the requirements of the journal, we have carefully revised the paper format and corrected the grammatical errors. The revised portions were highlighted in the marked-revised manuscript.
Independent Review Report, Reviewer 1
EVALUATION
The article describes the results of research on the effect of the addition of bamboo biochar and ZnO nanoparticles on the growth and chemical composition of maize as well as selected properties of soil contaminated with cadmium. The research concern to deal with the problem of the production of appropriate quality food and feed in contaminated areas, which is important on a global scale. The obtained results confirm some previous reports on the beneficial effect of biocarbon fertilization and the use of nanoparticles in plant production, indicating the possibility of their effective application also in the cultivation of maize on cadmium contaminated soils. Interesting work, proper methodology (slight additions indicated - details in the comments to the text). It should be emphasized that the study analyzed not only the characteristics and yield of plant biomass, but also the influence of the studied factors on many chemical properties of plants (for example chlorophyll content in leaves, photosynthetic rate, transpiration rate, MDA, activity of several enzymes, Zn and Cd concentrations) and selected soil properties (pH, AB-DTPA extractable Cd). The results are properly described (larger letters in the diagrams would be useful), the conclusions are correct, but it should be remembered that Cd is not the only stress factor in the analyzed soil after fertilization with sewage - the problem may be quite significant salinity or the presence of other, not analyzed contaminants. I suggest minor corrections (details in the form of comments to the text).
Response: Thank you very much for your comments. In accordance with the requirements of the journal, we have carefully revised the paper format and corrected the grammatical errors. We have revised the paper one by one according to the comments to the text. Please see the highlighted in the marked-revised manuscript.
- The larger letters in the diagrams would be useful.
Response：Thank you very much for your comments. We have changed the font in the diagrams to a larger size. Please see the Figure 1, 2, 3 and 4 in the revised manuscript.
- It should be remembered that Cd is not the only stress factor in the analyzed soil after fertilization with sewage - the problem may be quite significant salinity or the presence of other, not analyzed contaminants. I suggest minor corrections.
Response：Thanks for your positive suggestion. The soil samples used in this study were obtained from farmland around the mining area of Wang Yan Village. The solid mine waste is washed and leached by rainwater throughout the year, and toxic and harmful components enter the agricultural field located downstream with surface runoff. The term “wastewater” in the text was inaccurate, and the sentence was therefore rephrased as follows: “The soil was collected from the agricultural land of Wang Yan Village, which is located downstream of the mine site; the soil samples obtained from this area have been subjected to polluted surface runoff from the mine for 30 years. The initial properties of the selected agriculture land soil was only contaminated with Cd and other elements and salinity were below the threshold levels in the soil.” Please see the highlight in the marked-revised manuscript (Line 85-90).
We have replaced “mg/L, mg/kg” into “mg·L-1, mg·kg-1”, respectively. Please see the highlight in the marked-revised manuscript.
We have replaced “mg·g·L-1” into “mg·L-1”. Please see Line 113-115.
We have replaced “El” into “EL”.
We have replaced the maize plant height; spike length, height and width” into “the maize plant height; spike length, height, and width”.
We have replaced “replicates” into “replications”.
We have replaced “5” into “five”. Please see the highlight in the marked-revised manuscript.
We have deleted “Read et al., 2020” in Line 358.
Author Response File: Author Response.pdf
Reviewer 2 Report
Dear authors,
the presented manuscript is interesting and provides novel data on the use of biochar with nanosprays but it needs significant improvements in the presentation of the results. The presented graphs are not quite clear and I suggest you add the description of the x-axis on the graphs. The discussion could be improved, explain why did you use the "aged" wastewater? What is the significance of this? Add an explanation of why the soil was sampled from that particular site and also are the plants grown in pots or on plots, it is not quite clear from the material and methods. Significant improvements should be made.
Author Response
Dear editor and reviewers：
Thank you very much for your letter and the reviewer’s comments concerning our manuscript entitled “Bamboo biochar and zinc oxide nanoparticles improved the growth of maize (Zea mays L.) and decreased cadmium uptake in Cd contaminated soil” (agriculture-1872347). Those comments are all valuable and very helpful for revising and improving our paper. We have carefully revised the manuscript according to each comment referred by the reviewers. In accordance with the requirements of the journal, we have carefully revised the paper format and corrected the grammatical errors. The revised portions were highlighted in the marked-revised manuscript.
Independent Review Report, Reviewer 2
EVALUATION
The presented manuscript is interesting and provides novel data on the use of biochar with nanosprays but it needs significant improvements in the presentation of the results. The presented graphs are not quite clear and I suggest you add the description of the x-axis on the graphs. The discussion could be improved, explain why did you use the "aged" wastewater? What is the significance of this? Add an explanation of why the soil was sampled from that particular site and also are the plants grown in pots or on plots, it is not quite clear from the material and methods. Significant improvements should be made.
Response: Thank you very much for your comments. In accordance with the requirements of the journal, we have carefully revised the paper format and corrected the grammatical errors. Please see the highlighted in the marked-revised manuscript.
- The presented graphs are not quite clear and I suggest you add the description of the x-axis on the graphs.
Response: Thanks you very much for your comments. We have increased the resolution and size of the graphs and added a description of the x-axis to each graph. Please see the Figure 1, 2, 3 and 4 in the revised manuscript.
- The discussion could be improved.
Response: Thanks you very much for your comments. We have revised our discussion. Please see the highlight in the marked-revised manuscript (Line 338-344, 345-348, and 392-401).
- Explain why did you use the "aged" wastewater? What is the significance of this?
Response: The soil samples used in this study were obtained from farmland around the mining area of Wang Yan Village. The solid mine waste is washed and leached by rainwater throughout the year, and toxic and harmful components enter the agricultural field located downstream with surface runoff. The term “wastewater” in the text was inaccurate, and the sentence was therefore rephrased as follows: “The soil was collected from the agricultural land of Wang Yan Village, which is located downstream of the mine site; the soil samples obtained from this area have been subjected to polluted surface runoff from the mine for 30 years. The initial properties of the selected agriculture land soil was only contaminated with Cd and other elements were below the threshold levels in the soil.” Please see the highlight in the marked-revised manuscript (Line 86-91).
The selected land was under agricultural use, with the primary crops being maize and wheat. Therefore, it is necessary to develop an economical and effective method to remediate the compound pollution caused by heavy metal elements in soil. This study showed that the combined application of biochar and foliar spraying of nano ZnO can improve crop quality in cadmium-contaminated soil in future applications. We have added the significance of the selection of this sampling site to the introduction section of the re-vised manuscript. Please see Line 75-81.
- Add an explanation of why the soil was sampled from that particular site and also are the plants grown in pots or on plots, it is not quite clear from the material and methods.
Response：Thanks you very much for your comments. We apologize for the unclear presentation before.
The soil samples used in this study were obtained from farmland around the mining area of Wang Yan Village, which is located downstream of the mine site; the soil samples obtained from this area have been subjected to polluted surface runoff from the mine for 30 years. The initial properties of selected agriculture land soil was only contaminated with Cd and other elements were below the threshold levels in the soil. Therefore, the soil in this area met the requirements for our design pot experiment”.
We apologize for the unclear presentation before, and we have replaced “Total 48 plots” into “A total of 48 pots, please see Line 116.
We have added the new description in materials and methods part in this manuscript. Please see the highlighted in the marked-revised manuscript (Line 86-93).
We appreciate for Editors/Reviewers’ warm work earnestly, and hope that the correction will meet with approval. Once again thank you very much.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
Authors have improved the manuscript and the submitted revised version can be accepted for publishing
