Early Crop Identification Study Based on Sentinel-1/2 Images with Feature Optimization Strategy

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The work addresses a very interesting proposed related to the assess of the use of Sentinel-1 (S1) and Sentinel-2 (S2) data for the earliest identifiable time (EIT) for major crops in the Hetao Irrigation District (HID) of China. The manuscript is well written and shows an adequate theoretical framework. I have carefully read the work and consider that it is suitable for its publication in Agriculture. However, I have some observations to be considered in the final version. First, I think that it is important to highlight in the discussion section that the model adjusted to separate crops early can be applied in other regions and other years satisfactorily as long as the same production characteristics are present. In regions where crops are not irrigated but are rainfed and depend exclusively on rainfall, the climate usually generates changes in the phenological behavior of crops and in management decisions of farmers, changing the spectral and phenological signature of the crops. In this context, it is more difficult to adjust early detection models that can be applied to other years, making difficult their applicability in the future. On the other hand, I suggest to share a GEE repository to access to scripts that allow to assess the different steps of the data processing needed to adjust the model. 

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript tries to provide a strategy to early identify crops using Sentinel data. However, there are points to be addressed in the manuscript.

In general, introduction does not provide sufficient background to support the objectives, discussion section can be improved since few references were used and methodology are incomplete. Besides that, carefully check for the proper use of acronym/abbreviations.

 

Some specific points:

Aiming to improve the searching process and increasing the chances to be cited, the keywords should be improved, therefore, I’d suggest to avoid redundant words with the title as abbreviations/acronyms that are not commonly used.

 

Line 50-51 – Please check the meaning of MODIS.

 

What is the purpose of classifying crops before harvest if you know what crop has been planted?

 

Paragraph Lines 58-94 too large. 

Figures resolution and caption/legend have to be improved.

Authors have to present the relative “before harvest date” or “after planting date” of the sampling dates since most of the introduction is based on “n days prior harvest”.

Authors stated that clouds were removed, however details are missing.

The conclusion is not supported by the results and discussion (e.g., Lines 682 - 690.

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

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Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

The authors made substantial improvement.

If possible, I would recommend to improve the resolution of Figure 4. The content at the bottom has a poor resolution jeopardizing the understanding of the Figure.

Check for possible typos and writing style (e.g., Line 623 - "Please refer to Figure 7 for detailed results" - I would recommend to avoid using this writing style in the scientific writing)

Legends are still missing in Tables and Figures. If you add an abbreviation/acronym, you have to present its legend, otherwise the reader won't be able to properly interpret the Table/Figure. In addition, I would suggest to use the extensive form instead of abbreviation/acronym in the caption.

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Thanks for the authors' contribution on the revision of the manuscript. I have checked the revision and authors' response to my comments, it is acceptable at present format.

Author Response

Thank you for your thorough review and positive feedback on our manuscript. We greatly appreciate your careful consideration of our revisions and comments. We are glad to hear that the current structure/format meets your approval.

If there are any additional adjustments needed or further steps in the publication process, please do not hesitate to let us know. We look forward to continuing our collaboration and finalizing the manuscript according to the journal's requirements.