Validation of an In-Situ Observation Method for Nonpoint Source Pollution in Paddy Fields: A Case Study of a Beijing Paddy Field
Round 1
Reviewer 1 Report
Dear authors:
I read your manuscript and detected some major problems. In point of view, besides the comments regarding the methodology, I believe you need to provide a link between ET+F and the load of chemicals. It seems a separated study since I couldn't see any connection between. Maybe IO method is able to provide estimates of the chemicals? If so, it needs to be scientifically stated in the manuscript and put as one of the purposes.
I attached the pdf file with some comments throughout the manuscript. Please, check them carefully.
Good luck.
Comments for author File: 
Comments.pdf
Author Response
Please see the attachment
Author Response File: Author Response.pdf
Reviewer 2 Report
The question is how to solve the problem of overfertilization of fields with artificial fertilizers, is the research intended to improve the situation for farmers? Will the environment gain from it? Will the established devices improve water management and protection activities? These answers should be in the "conclusion" section.
The paper does advance the field in a substantive way, and in my opinion is worthy of publication.
The article is well prepared in terms of editing. Some few editorial errors are present in the manuscript:
Page 1 line 25, 29, 32, 35, …. , Page 2, Page 3 …. – should be a space. Please check word spacing on each page.
Page 3 line 90, 91 – should be written in SI
Page 6 – Illegible Figure 2, depth unit ?, perhaps the introduction of differentiated lines would help the analysis.
Author Response
Please see the attachment
Author Response File: Author Response.pdf
Reviewer 3 Report
The abstract should contain information about what was done and for what purpose. The conclusions presented are obvious without research. If there is a goal, it will make sense. Likewise, in the introduction, the purpose of the analyzes should be clear and why such studies were undertaken. Conclusions cannot repeat the results. There is little discussion of the results with the literature in the results and discussion section. Other minor remarks in the text. Please pay attention to the records of the units.
Comments for author File: Comments.pdf
Author Response
Please see the attachment
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The paper is in a good shape for now. Good work made by the authors. From my side, there is no any further comments.
This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.
Round 1
Reviewer 1 Report
The authors must look after the the English grammar and language throughout the manuscript for publication of scientific work. Suggesting to check the grammar and language by professionals. Specific comments are embedded in the .pdf file.
Comments for author File: Comments.pdf
Reviewer 2 Report
Regarding the IO method, the savings in labor and cost are an advantage, and once this method is established, measurements in the field will become easier. However, the purpose of this paper is unclear, their accuracy and applicability are not verified, and if this is the purpose of the paper, I am not sure if the analysis can support the conclusion. From the abstract, it could read as the purpose is to study the effect of the location of the installation and the number of water level gauges, but the experiment does not seem to be designed to achieve the objective (changing the location, increasing or decreasing the number, etc.). If water depth alone can be used to predict evapotranspiration and infiltration, it is necessary to show that it is able to use the estimated data by the proposed method after comparing it with the Et and F measured by previous conventional methods. In the absence of this, the discussion that follows is merely an indication of the possibility. Even if the purpose of this paper is not to verify the results, it is necessary to provide support for why the proposed method is able to use. Overall, the paper is very difficult to read because of many notation errors and lack of definitions. In addition, there are many mistakes and insufficient descriptions of technical terms, which need to be revised significantly.
Specific comments are below
L.2 The title is too abstract and inappropriate.
L.40-57 The introduction focuses on a review of the methodology, but it is still lacking. For this reason, it is difficult to understand the novelty of this paper compared to previous studies.
L.54-56 Specific issues should be mentioned. This may make it easier to understand the importance of this paper.
L.54-57 It is mentioned that the IO method needs to be verified, but the reason why you chose the IO method is not mentioned.
L.98-100 If you verify the effect of the location of installation, showing map of the experimental field is helpful. We don't know the distance between the inlet and outlet of the field and how far away the observation points are.
L.105-110 There is no mention about chemical analysis methods of COD and nutrients.
L.114-115 "Water depth hydrograph" is incorrect because "hydrograph" is defined as a graph showing "discharge" versus time.
L.118-119 It is difficult to understand "different scenario". You need to mention what is the scenario is.
L.120 What is the "artificial" drainage? I think "drainage" or "irrigation" is come from human activities which is eventually "artificial".
L.132 Definition of "Rout" is different between several parts in this paper. It's "the numbers of outflows" in L.178, although "the farmland export" in L.250. I don't know which explanation is correct, but it should be unified or be assigned different parameter names.
L.134-137 Infiltration loss (F) is strongly depended on water depth with non-linearly changing. How do you assume this?
L.139 Explanation of "artificial irrigation" here is different from the description in L.143.
L.141-144 The reason why you choose "median" should be mentioned here. Infiltration rate has potentially higher influence on (E+F) because it would be increased with rising water level, especially, the former experimental field was dry land three years ago.
L.149 Please show us "other periods" means what kind of period for example.
L.150 It is not a hydrograph.
L.151 You should mention that the water depth at 8:00 was lower than the initial depth. Plus, the unit of precipitation should be shown appropriately (mm/30min?).
L.156 What is "rainfall scenario"? You need to mention what is the scenario is.
L.169-170 It is difficult to understand the "process" in "pollution concentration variation process". It looks like just a variation of the concentrations.
3. Results and Discussion -> I think it is necessary to compare between the estimated (E+F) and observed E and F by conventional methods because the (E+F) is still unreliable to go further discussion. I recommend adding more data to concrete the confidence of the estimated values. Unless it, the results and discussion here is showing just a possibility.
L.182-183 There was about 10mm water depth difference between point#1 and #2. Which means water was flowing between the points due to hydraulic gradient of 10mm. It is correct? How accurate the water depth measurement including sensor installation?
L.190 Is the unit of water depth and precipitation daily basis (mm/day)?
L.191 What is the "process lines"?
L.214-216 It is hard to understand the relation between sunning time and occurrence of zero water depth. Please add more detail about this and add the data about sunning time as well.
L.236 What is the "overflow types"? Please add how did you classified the types and is come from estimation or observation-based.
L.238 What are "runoff loss" and "return flow loss"?
L.240 What is "water export"? How did you calculate it?
L.243 What kind of errors of "uncontrollable errors" for example?
P.7 Table1 Definition of "Win" should be mentioned in methods.
L.252 It is not a hydrograph.
L.257-287 The overall impression is that the content of the discussion is lack and I don't know what you are trying to say.
L.281, L287 There are no table 3 and 4 in this manuscript.
L.310-311 What kinds of substances COD required by paddy field are?
L.317-320 The sentence looks like a small conclusion of this section, but it seems to be consisted of referring previous works. Plus, you can mention about low water depth irrigation, but it doesn't satisfy to the objective of this paper.
L.358 There is no information that the observation points were located on low-lying area, therefore you should mention it in the method section.
