Novel Curve Fitting Analysis of NDVI Data to Describe Turf Fertilizer Response

Round 1

Reviewer 1 Report

First of all, I want to congratulate the authors for their efforts in this manuscript. The authors presented their results detailing the use of NDVI to estimate the response of turf to fertilizer, creating fitting curves. The paper is well-structured and deals with an important issue. The paper has some issues which must be addressed before accepting it. Following, I include a list of comments aimed at enhancing the quality of the paper:

The abstract has to be rewritten. It must start with a short description of the problem that the authors are investigating. Then, the aim of the paper has to be established. A sentence summarizing the material, methods, or conducted experiments should be included. Then, the abstract has to highlight the results.

Consider in the introduction more context about the use of NDVI for turfgrass. Add examples in which other technologies for monitoring water or nitrogen scarcity are used, such as 10.1016/j.agwat.2022.107581 and 10.1002/csc2.20726)

Including a map of the area where the tests are conducted is recommended.

Details about the weather in the area where the turfgrass was kept, as well as provided irrigation, must be included.

The description of phytosanitary treatments should be described in a new subsection. It cannot be merged with the site description.

All the acronyms must be defined. Please define HSD and check other cases in which the acronyms are not defined.

The results must be divided into different subsections providing more detailed comments and analysis. The authors have to explain the different patterns of graphics included in Figures 1 and 2.

Figures 3 to 6 are too big; please reshape the Figure to ensure that the letter size of the Figure is similar to the letter size of the main text.

The discussion section should be divided into different subsections presenting each key aspect of their research. Moreover, in the discussion, the authors must include a comparison with the current solutions to the same problem and consider including the papers already cited in the manuscript and new ones. Finally, the limitations of the performed study must be highlighted and justified. Consider linking this with future work.

 

Future work should be added in an independent paragraph at the end of the conclusions.

Author Response

Thank you for your review and comments.

Please see attachment for our responses.

Reviewer 2 Report

Thie paper describes a method for characterising canopy reflectance of turfgrass so as to help differentiate responses to nitrogen fertilization treatments.

The paper is generally well written, coherent and concise and is surely of interest to the readers of this journal.

I don't have significant concerns regarding the methodology.  However I think a few things need to be made clearer or more explicit.

l143 - Eq.1 seems to come out of nowhere.  Can you explain more information as to where this function came from and why it was chosen.  Furthermore, can you indicate what fitting procedure was used? eg. Ordinary Least Squares?

l265 indicates that the function is relatively easy to fit, but again, I think the basic details are necessary.  I'm not sure these details belong in the discussion section.

I do like the interpretability of the model whereby parameters B and C have specific meanings.  However I don't think this was explicitly mentioned earlier in the document when the equation was initially presented.

l93 & l160 - The degrees symbol looks wrong here. Should be U+00B0 (see l123)

l115 - In this paragraph, there is mention of days before treatment and dates such as mid-May and late September.  I may have missed them, but I don't think I could find a specific date when treatments were applied. eg. what date is DAT=0?

Figure 2, the curves fitted for 40:60, 60:40 and 80:20 on visual inspection don't look particularly great at estimating the maximum - can you make reference to this in the text - I'm not sure I'm convinced by the choice of function given an initial glance at this (although I don't think this is significantly impacting the results in this case).  In the paragraph starting l272, only issues with the tails are mentioned as being of note - is this absolutely the case?  If not, maybe something could be added here to note issues with determining the maximum also?  Also some of the tails seem noisy - what are potential reasons for variability between replicates?  Why does 20:80 have quite a tight tail, but 60:40 have a wide tail?  I think it would be helpful to the reader to mention potential reasons for this.

Finally, the fitting of the data, it's not clear what is being minimized here?  Is it each individual data for all replicates? or do you aggregate replicates and fit to the aggregate? such as the mean?

Figure 2, It's helpful to assign subplots a letter, a), b), ... f). and be explicit in the figure caption what the graphs show.

l186 & 209 - p=0.05? This looks odd, is this the significant level? or maybe p < 0.05?

Table 2 - explain what "msd" stands for in the text, for those who are unfamiliar with Tukey's MCT.

Figure 3 - "Curve fitted to ..." - It doesn't look much like a curve to me, even less so looking at the equation.

5. Conclusions - Do you have any suggestions for the future work?  Or what comes next?  How can the methodology be improved?

 

Author Response

Thank you for your review and comments.

Please see the attachment for our response.

 

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The authors have addressed some of the comments. The following ones must be still solved:

The discussion section should be divided into different subsections presenting each key aspect of their research. Moreover, in the discussion, the authors must include a comparison with the current solutions to the same problem and consider including the papers already cited in the manuscript and new ones. Finally, the limitations of the performed study must be highlighted and justified. Consider linking this with future work.

 

Author Response

Thank you for your comments and continued commitment to the improvement of the manuscript. 

A paragraph has been added (273-281) that compares the novel method and its advantages to the traditional way the NDVI data is typically presented in research. We believe this explanation is sufficient to show how this method differs and allows for different interpretation of the data.

The limitations of the research are specifically addressed (303-306) we believe this appropriately addresses the concerns and shows that further confirmation of the method is still necessary more explicitly. the following sentence links this with potential future work.

After reviewing a number of manuscripts recently published in the journal we have concluded that the format we are presenting this discussion in is customary for the journal although  we do understand papers are presented in both ways. This stylistic difference in how the results are discussed is not essential to the review of the content of the science, nor does our format differ significantly from other articles currently being published in this journal. Also we used the the template provided by the journal to produce the draft.  For this reason and for continuity of the draft from other reviewers who did not see this as essential we have chosen to leave the format as is.