Effects of Spent Drilling Fluids from Natural Gas Fields on Seed Germination and Root Development of Maize (Zea mays L.)
Round 1
Reviewer 1 Report
Overall this is a fairly straightforward investigation regarding drilling fluid's phytotoxic and cytotoxic effects on seed germination and root development. It is meaningful that this study can help to evaluate the possibility of reusing this industrial waste in the context of increasing drilling activities. It is fairly good written but perhaps lacks a bit of polishing.
Introduction.
Line 48-51: There are lots of types of drilling fluids, such as oil-based, water-based, etc, and its toxicity will have a big different due to the components of drilling fluid. Furthermore, the characterization of drilling fluids is used to determine loading rates that will prevent the topsoil/waste mix from exceeding salt, hydrocarbon and trace elements endpoints. This manuscript did not clarify which type of drilling fluid they used, and why.
Line 58: For disposal purposes, most countries require the drilling waste must be sampled and in compliance with the appropriate disposal criteria. What’s the regulation for drilling fluids’ disposal in your study region?
Line 75-77: Please give more details why this study is only focused on drilling fluids’ effects on maize, or land application drilling fluids to agricultural land?
Experiment Design.
Line 95-96: Please clarify the reason to choose these loading rates. It sounds the soil types, plant species, and drilling fluid types are different between this study and the referenced research. Also it’s not clarify how it’s been transferred to the rates by X%, which used in treatments by this experiment.
Results.
Line 184: What’re the main components of this drilling fluid?
Discussion.
Line 435: On the basis of these results, what’s suggestion for reusing drilling fluids in land reclamation?
Author Response
Please see the attachment!
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Manuscript ID: applsci-447734
Title: Effects of spent drilling fluids from nature-gas field on seed germination and root development of maize (Zea mays L.)
I have reviewed the manuscript titled ‘Effects of spent drilling fluids from nature-gas field on seed germination and root development of maize (Zea mays L.)” My evaluation is as follows:
The manuscript contains original research on the use drilling waste for land reclamation. The authors have provided a discreet experimental setup to determine the effects of spent drilling fluids on the growth of maize plant particularly emphasizing on maize seed germination. The focus is topical and provides a robust observation on the potential of spent drilling fluids to be used as a soil amendment for increased agricultural productivity and environmental sustainability.
The introduction is well written and referenced. However, the authors have not explicitly indicated the aim and clear objectives of the study and I propose that this should be clearly stated. The methodology and results sections are well written. However, the authors have collected many variables some of which are not used anywhere and whose applicability in the study are not clear. In regard to this, I propose that the authors lay more emphasis on the important variables and give more details on those. In the results section, it would be beneficial if the authors will directly link the observations in the germinating seeds with SDF characteristic. This has not been clear in both the results and discussion chapters where the authors have attributed the observed characteristics of the germinating seeds in a general manner instead of linking the same to specific SDF attributes. For example, in line 355 – 357, SOD, POD and APX showed increased activity. What SDF characteristics were responsible for this observation?
Minor corrections:
Line 22 – delete “been” between have and not
Line 26 – provide the full description of ROS
Line 54 – the authors mention of synthetic macromolecule polymers based on natural plants use which are pollution free and biodegradable, was this what they used?
Line 69 – replace were with did and delete the.
Line 73 – what do the authors mean by “barely”?
Line 86 – the authors state of elucidating on the effect of SDF on the genome of higher plants. Is this what their objective was? Do they mean phenotype or both genotype and phenotype? This should be made clear. The best way to do this is by clearly stating the study objectives
Line 99 – replace used with grown
Line 109 – the constants of concern should be named
Line 129 – the equation should be named equation 2 since the one in line 122 has been named 1.
Line 132 – how did the authors identify the six seed used to measure root length?
Line 162 – add d to use.
Line 163 – measuring methodology for electoral conductivity was not described earlier as stated. However, it can be said that would be done as per the cited reference provided.
Line 169 – FAA used without providing full description
Line 171 – provide full description for W/V
Line 172 – the (symbol) ~ cannot be used in between numbers.
Line 193 – replace markedly with significantly
Line 272 – replace the word provoke to a more suitable word
Line 284 – 292 can be taken to the introduction section
Line 294 – remove ity from the word phytotoxicity.
Line 411 – remove ly from the word significantly
Author Response
Please see the attachment!
Author Response File: 
Author Response.docx
Round 2
Reviewer 1 Report
N/A
