Quadcopters in Smart Agriculture: Applications and Modelling

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This paper reveiw the quadcopters in smart agriculture, this is the  promising direction in the future. However,  there exist some apparent defects.

1. While many references are cited in the paper, the authors do not provide in-depth analysis of them. For example, Line 180-195, the authors only described the quadcopters used in the Chemical spraying, why not  discussed the advantages and disadvantages of the each scheme.

2. The Model of Quadcopters depiced in the paper too simple and author do not analyse the each equations.

3. The challenges described in the article are common to drones across all applications, not specific to agricultural environments or agricultural applications

 

Furthermore:

    The pictures of the paper are too large, it is recommended to minimize and optimize it , and the picture background is too messy. For example, in Fig 5, it is impossible to see the details of the drone.

 

Author Response

Thank you very much for taking the time to review this manuscript. We sincerely appreciate your feedback, which has contributed in one way or another to improving the clarity of our work. Please find the detailed responses below and the corresponding revisions/corrections highlighted/in track changes in the re-submitted files.

Comment 1: While many references are cited in the paper, the authors do not provide in-depth analysis of them. For example, Line 180-195, the authors only described the quadcopters used in the Chemical spraying, why not  discussed the advantages and disadvantages of the each scheme.

Response 1:

Thank you for your valuable comment. We understand the importance of providing in-depth analysis, and we believe we have addressed this at the end of Section 3,”Agricultural Application of Quadcopters”. Rather than simply enumerating the quadcopters used in the mentioned agricultural applications such as chemical spraying, we selected significant examples from each application to cover them all and presented them in Table A1. In this table, we carefully identified the limitations of each study and provided specific recommendations to overcome the challenges, aiming to facilitate future advancements in the field. This approach allows for a more focused and practical discussion, highlighting the critical aspects of each scheme in a structured manner.

Comment 2: The Model of Quadcopters depiced in the paper too simple and author do not analyse the each equations.

Response 2:

Thank you for pointing out that. The model presented in this paper is generic, designed to be applicable to any type of quadcopter. The vector containing the forces and torques can be adjusted based on the specific quadcopter type and mission requirements. By choosing a generic model, we provide a flexible framework that researchers can adapt and build upon for various applications. However, in response to your comment, we have added further analysis to evaluate and elaborate on the equations presented in the manuscript. These changes are highlighted in the re-submitted manuscript for better clarity.

Comment 3: The challenges described in the article are common to drones across all applications, not specific to agricultural environments or agricultural applications.

Furthermore:

    The pictures of the paper are too large, it is recommended to minimize and optimize it , and the picture background is too messy. For example, in Fig 5, it is impossible to see the details of the drone.

 

Response 3:

Thank you for your comment. While it's true that the challenges we described, such as resource consumption, data processing, environmental factors, dynamic obstacles, and security threats are commonly found across various drone applications, they are particularly significant in the context of agriculture. In the challenges part presented in this paper, we have oriented our analysis specifically towards the agricultural sector, using examples and references directly related to agriculture.

These challenges affect the agricultural environments, where factors such as unpredictable weather conditions, large-scale data from vast fields, and the need for secure management of sensitive agricultural data play crucial roles. For this reason, even though these issues may appear in other fields, they are commonly encountered in agriculture and must be thoroughly addressed to improve the effectiveness of quadcopters use in smart farming.

We have focused on elaborating these challenges with a specific emphasis on agricultural applications, as they are critical to the success of quadcopter deployment in this sector.

As for the second part of the comment, we have reduced the size of the images as requested and replaced Figure 5 with another image that shows more clearly the details of the quadcopter.

Reviewer 2 Report

Comments and Suggestions for Authors

This paper presents a relatively comprehensive exposition of the role of quadcopters in smart agriculture, and discusses the various applications of quadcopters in smart agriculture, such as chemical spraying, irrigation, crop mapping and monitoring, planting and seeding, and plant health assessment. In general, this paper has certain research merit, but it requires further improvement and refinement in the following aspects to enhance the quality and academic level of the paper.

 

1. Regarding the reliability of the data and conclusions in the article, some application cases lack detailed descriptions of the data sources and processing methods, which may undermine the credibility of the conclusions. It is recommended to supplement relevant information.

2. The article employs a comparative analysis method, and it could further consider incorporating actual case analyses to bolster the persuasiveness of the research.

3. The structure of the article is clear and the logic is coherent, yet the transitions between some sections are somewhat rigid. It is suggested to optimize the connections between paragraphs to render the article more fluent.

4. The usage of some terms is not uniform, and it is recommended to unify and standardize them.

5. In terms of agricultural application cases, the article could include more examples from different regions and various crop types to better illustrate the wide applicability and effectiveness of quadcopter drones in smart agriculture.

6. Based on the current research status and literature analysis, the author should explicitly identify the key issues and potential directions that need to be addressed in future research.

7. The conclusion section of the article summarizes the main content of the article, but it is not sufficiently concise and clear. It is suggested to distill the key points and highlight the core conclusions of this paper.

Comments on the Quality of English Language

Minor editing of English language required.

Author Response

Thank you very much for taking the time to review this manuscript. We sincerely appreciate your feedback, which has contributed in one way or another to improving the clarity of our work. Please find the detailed responses below and the corresponding revisions/corrections highlighted/in track changes in the re-submitted files.

Comment 1:  Regarding the reliability of the data and conclusions in the article, some application cases lack detailed descriptions of the data sources and processing methods, which may undermine the credibility of the conclusions. It is recommended to supplement relevant information.

Response 1:

Thank you for your valuable feedback. In response to your comment regarding the reliability of data in the conclusions, we have taken the necessary steps to improve this aspect by supplementing section 5, “Challenges and Future Directions”, with additional references that provide more detailed information about the data sources. These references help clarify the context and improve the credibility of the conclusions. All these revisions have been highlighted in the re-submitted manuscript for better clarity.

Comment 2: The article employs a comparative analysis method, and it could further consider incorporating actual case analyses to bolster the persuasiveness of the research.

Response 2:

Thank you for your insightful comment.  We have added and elaborated on several actual cases in subsection 2.1, “Commercial Quadcopters”, for each type of commercial quadcopters. The new examples are highlighted in the re-submitted manuscript for clarity. We believe these additions enhance the persuasiveness of our research.

Additionally, we would like to note that different actual cases are also presented throughout the manuscript, such as in Table 3, which highlights various custom-built quadcopters used in agricultural missions. Furthermore, numerous real-world examples are provided for each agricultural application discussed in Section 3, “Agricultural Applications of Quadcopters”.

Comment 3: The structure of the article is clear and the logic is coherent, yet the transitions between some sections are somewhat rigid. It is suggested to optimize the connections between paragraphs to render the article more fluent.

Response 3:

Thank you for pointing this out. To ensure smoother transitions between some sections, we have updated our manuscript accordingly by adding transition sentences where necessary. All these modifications are highlighted in the re-submitted manuscript for clarity.

Comment 4: The usage of some terms is not uniform, and it is recommended to unify and standardize them.

Response 4:

Thank you for your comment. We found that the terms used in Figure 11 and the terms x, y, and z in Table 4 do not match their occurrences in other parts, such as Equations 2 and 3 due to some typographical mistakes in LaTex. Therefore, we have standardized and unified all terms throughout the manuscript. The changes are done in Table 4, Figure 11, lines 321, 324, and 326 in the old version and all of them are highlighted in the re-submitted manuscript for better clarity.

Comment 5: In terms of agricultural application cases, the article could include more examples from different regions and various crop types to better illustrate the wide applicability and effectiveness of quadcopter drones in smart agriculture.

Response 5:

Thank you for pointing out that. The initial manuscript already presented various examples applied in different countries, such as “Guangzhou and Changji, China” in line 185, “United States Department of Agriculture (USDA)” in line 200, “Yargullen, Queensland” in line 209, “Hyderabad, India” in line 211, “Limpopo Province, South Africa” in line 212, “Nanning, China” in line 216, “Northern Italy” in line 225, “Eschikon, Switzerland” in line 232, “West Java” in line 243, “Tando Adam, Sindh, Pakistan” in line 262, and “Brazil” in line 283. All of these countries were mentioned in Section 3,”Agricultural Applications of Quadcopters”, to illustrate the wide applicability of quadcopters in smart agriculture. Additionally, in Table 3, the second column includes the organizations involved in these projects, highlighting entities from different countries, including India and Australia.

 Furthermore, to include more examples, the new manuscript features additional cases, as mentioned in Response 2, where we specifically mentioned the countries in which each application occurred. For example, “Ventaquemada, Boyacá, Colombia” in line 127, “Idaho, United State” in line 137, “Flakkebjerg, Denmark” in line 143, “Hyderabad, India” in line 150, “Middle-Atlas Mountains in Morocco” in line 159, “Homestead, Florida, United States” in line 169, and “Chimaliro, Thyolo District, Southern Malawi” in line 180.

Comment 6: Based on the current research status and literature analysis, the author should explicitly identify the key issues and potential directions that need to be addressed in future research.

Response 6:

Thank you for your comment. In Section 5, “Challenges and Future Directions”, we examined the challenges faced in this field and proposed future research directions below each challenge, such as solar-powered quadcopters, path optimization algorithms, cybersecurity measures, and more. We presented various ideas for future directions that can be applied in quadcopter-based applications in smart agriculture, aimed at enhancing the field and promoting further development. These proposed future directions have been highlighted in the re-submitted manuscript for better clarity.

Comment 7: The conclusion section of the article summarizes the main content of the article, but it is not sufficiently concise and clear. It is suggested to distill the key points and highlight the core conclusions of this paper.

Response 7:

Thank you for this comment. We have updated our conclusion to include the core contributions of this paper and to highlight the key points. All changes have been highlighted in the re-submitted manuscript for better clarity.

Response to comments on the quality of English language:

We have revised the manuscript and found some typographical errors, which we have corrected. If there are any further changes needed after reviewing the resubmitted file, please let us know the specific locations in the manuscript, and we would be happy to make those corrections.

Reviewer 3 Report

Comments and Suggestions for Authors

The study reviewed Quadcopters application in Smart Agriculture. Below are my comments:

1.      What was the objective of this paper? Needs to be clearly mentioned, Furthermore, the manuscript needs to be rearranged accordingly. Currently the arrangement is not as per the standard journal format.

2.      Delete line 67 to 72. Not required in the manuscript as it is just stating about the manuscript.

3.      Very few commercial drones are discussed. Can you provide a table with all the commercial drones available in the market?

4.      The language of the paper is not standard for the manuscript. It might be good for a report or thesis. Kindly revise all the manuscript, specifically the places where figures and references are mentioned in the text.

5.      Please mention the future research work needed in the quadcopter application in agriculture based on the findings of this study.

6.      Table A1 is not proper and needs to be thoroughly modified. Put reference in th last column, don’t mention the paper title in the column rather the main objective of the study with specific findings.

7. Other comments are provided in the attached manuscript.

Comments for author File: Comments.pdf

Comments on the Quality of English Language

Need improvment in language of the paper. 

Author Response

Thank you very much for taking the time to review this manuscript. We sincerely appreciate your feedback, which has contributed in one way or another to improving the clarity of our work. Please find the detailed responses below and the corresponding revisions/corrections highlighted/in track changes in the re-submitted files.

Comment 1: What was the objective of this paper? Needs to be clearly mentioned, Furthermore, the manuscript needs to be rearranged accordingly. Currently the arrangement is not as per the standard journal format.

Response 1:

Thank you for your comment. For the first part of this comment: This paper presents a survey of quadcopters’ use in smart agriculture by discussing its various types, applications, and modelling techniques. The objective of the paper is clearly stated in the abstract such as “this paper provides a comprehensive survey of quadcopters’ use in smart agriculture and offers researchers and engineers valuable insights into this evolving field, presenting a roadmap for future enhancements and developments.” and “To explore the different aspects of quadcopters’ use in smart agriculture, this paper focuses on the following: (a) the unique advantages of quadcopters over other UAVs, including an examination of quadcopter types particularly used in smart agriculture; (b) various agricultural missions where quadcopters are deployed, with examples highlighting their indispensable role; (c) modelling of quadcopters, from configurations to the derivation of mathematical equations, to create a well-modelled system that closely represents real-world conditions; and (d) challenges that must be addressed, along with suggestions for future research to ensure sustainable development”. The objective is not only mentioned in the abstract but also reiterated throughout the paper, including the introduction, body, and conclusion, using phrases such as “this paper examines”, “this paper explores”, “this paper focuses on”, etc. Please, if you feel that these clarifications are insufficient, we would greatly appreciate any suggestions you may have.

For the second part of this comment: The structure of this paper follows the MDPI Applied Sciences Journal format. We adhered to the guidelines provided on the journal's website under the 'Instructions for Authors' in the 'Manuscript Preparation' section. The LaTeX template was downloaded from there, and the paper was prepared accordingly, as reflected in the submitted LaTeX file. Our survey paper is properly organized based on the journal's instructions, starting with the front matter (e.g., title, author list), followed by the research manuscript sections (e.g., introduction, body, conclusion), and concluding with the back matter (e.g., author contributions, references). Everything was formatted in line with the journal's template guidelines. If there is any aspect that does not conform to the journal’s instructions, could you kindly point it out so we can make the necessary corrections?

Comment 2:  Delete line 67 to 72. Not required in the manuscript as it is just stating about the manuscript.

Response 2:

Thank you for your valuable comment. However, we included an outline of the paper’s structure at the end of the introduction to enhance clarity, especially given the length of our paper. Authors frequently provide a brief overview of the sections following the introduction, particularly in comprehensive reviews and surveys, which is the case with our paper. Many review papers published in MDPI Applied Sciences Journal follow this common practice, and we have provided a list of examples below for reference:

• Vergara, D., Lampropoulos, G., Fernández-Arias, P., & Antón-Sancho, Á. (2024). Artificial Intelligence Reinventing Materials Engineering: A Bibliometric Review. Applied Sciences, 14(18), 8143.
• Comi, A., & Idone, I. (2024). The Use of Electric Vehicles to Support the Needs of the Electricity Grid: A Systematic Literature Review. Applied Sciences, 14(18), 8197.
• Fernando, X., & Lăzăroiu, G. (2024). Energy-Efficient Industrial Internet of Things in Green 6G Networks. Applied Sciences, 14(18), 8558.
• Van Gelderen, L., & Tejedor-García, C. (2024). Innovative Speech-Based Deep Learning Approaches for Parkinson’s Disease Classification: A Systematic Review. Applied Sciences, 14(17), 7873.

However, if you believe that this practice is not appropriate for our survey paper, unlike the other published papers, please let us know.

Comment 3: Very few commercial drones are discussed. Can you provide a table with all the commercial drones available in the market?

Response 3:

Thank you for pointing out that. This paper focuses specifically on quadcopters in smart agriculture and not on all types of drones. Therefore, in subsection 2.1, "Commercial Quadcopters," we do not explore all types of commercial drones available in the market; we only examine existing commercial quadcopters that are found in the literature to be frequently used in various agricultural missions. All their specifications and agricultural applications are also provided in the paper for further validation of their various agricultural uses. If you believe there is a specific commercial quadcopter presented in the literature that is applied in various agricultural applications and that we have not mentioned, please let us know.

Comment 4: The language of the paper is not standard for the manuscript. It might be good for a report or thesis. Kindly revise all the manuscript, specifically the places where figures and references are mentioned in the text.

Response 4:

Thank you for your comment. However, in this paper, the in-text citations follow the format of the MDPI Applied Sciences Journal. We adhered to the guidelines provided on the journal's website under the "Instructions for Authors" in the "Manuscript Preparation" section and the "Preparing Figures, Schemes, and Tables" section. The LaTeX template was downloaded from there, and the paper was prepared accordingly, as reflected in the submitted LaTeX file. All figures and tables are inserted into the main text close to their first citation, numbered according to their sequence of appearance (Figure 1, Table 1, etc.), and include titles and captions. They are cited appropriately when referred to in the text. We revised the manuscript and checked all in-text citations for references and figures, ensuring compliance with the MDPI guidelines. If you notice any instances where in-text citations are incorrect and need correction, please specify their locations in the manuscript.

Comment 5: Please mention the future research work needed in the quadcopter application in agriculture based on the findings of this study.

Response 5:

Thank you for pointing out that. In section 5, “Challenges and Future Directions”, we examined the challenges faced in this field and proposed future research directions below each challenge, such as solar-powered quadcopters, path optimization algorithms, cybersecurity measures, and more. We presented various ideas for future directions that can be applied in quadcopter-based applications in smart agriculture, aimed at enhancing the field and promoting further development. These proposed future directions have been highlighted in the re-submitted manuscript for better clarity.

Comment 6: Table A1 is not proper and needs to be thoroughly modified. Put reference in th last column, don’t mention the paper title in the column rather the main objective of the study with specific findings.

Response 6:

Thank you for your valuable comment. We agree with this comment and have modified Table A1 accordingly, placing the reference in the last column and replacing the paper title with the objective. These changes have been highlighted in the re-submitted manuscript for better clarity.

Comment 7:  Other comments are provided in the attached manuscript.

Response 7:

Thank you for your comments and time. Kindly find below our responses for each comments added in the attached file:

• “No need to provide this section. Readers can easily go through the paper and understand through the subtitles.”: It is addressed in Response 2.
• “Convert this into a paragraph.”: We appreciate your suggestion. We have elaborated on each bullet point, and these changes are highlighted in the re-submitted manuscript. However, we chose to retain the bullet format because converting the information into a paragraph would result in a lengthy text, which may cause readers to lose focus while going through all the features. The bullet format allows for clearer separation and easier comprehension of each feature.
• “How mavic 2 was used for spraying purpose as it is only a photography drone.”: The Mavic 2 was used to detect and classify weed species, and create efficient herbicide maps and spray patterns to minimize the amount of herbicide applied. More details can be found in reference [93]: “Hobba, B.; Akıncı, S.; Goktogan, A.H. Efficient herbicide spray pattern generation for site-specific weed management practices 660 using semantic segmentation on UAV imagery. In Proceedings of the Australasian Conference on Robotics and Automation 661 (ACRA-2021), 2021, pp. 1–”.
• “Format as per journal. Put reference in th last of the paragraph. This is applicable for all the sections.”: Thank you for your comment. We have adjusted the placement of the reference citations within the text to ensure they align with the meaning of each sentence, as each sentence corresponds to a specific reference. Placing all citations at the end of the paragraph would not accurately reflect this. All these changes have been highlighted in the re-submitted manuscript for clarity.
• “Put reference is last column.”: It is addressed in Response 6.
• “In this column give work done, not the paper title.”: It is addressed in Response 6.

Response to comments on the quality of English language: The first author of this paper is a native English speaker from the United States, the second author has lived in Australia for an extended period, and the third author studied in the United States. Therefore, we believe that the English used in this paper is of good quality, reflecting both American and Australian standards. We have revised the manuscript and found some typographical errors, which we have corrected. If there are specific parts of the paper that require extensive editing of English language as mentioned, please indicate them in the manuscript, and we will be happy to address them.

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

As a review, it should be discussion on the future direction and trend of the quadcopters deeper, However, the future discussed in this paper does not focus on the application of drones in the field of agriculture. I suggest that the author focus more on the application of agriculture in the future trend.

Comments on the Quality of English Language

Minor editing of English language required.

Author Response

Comment: As a review, it should be discussion on the future direction and trend of the quadcopters deeper, However, the future discussed in this paper does not focus on the application of drones in the field of agriculture. I suggest that the author focus more on the application of agriculture in the future trend.

Response:

Thank you for your valuable feedback. We have thoroughly revised the manuscript to address your suggestion. Specifically, we have explored the discussion on the future directions of quadcopters in smart agriculture by incorporating detailed examples that highlight their potential applications in this field. By placing greater emphasis on the latest trends in quadcopter-based agricultural applications, such as solar-powered drones, cloud computing for real-time crop monitoring, and advanced obstacle detection sensors for collision avoidance during flight, we believe the manuscript now offers a more comprehensive analysis of future trends in smart agriculture. All changes have been highlighted in the re-submitted manuscript for clarity.

Response to comments on the quality of English language:

We have carefully revised the manuscript and corrected all typographical errors. If there are any further changes needed after reviewing the resubmitted file, please let us know the specific locations in the manuscript, and we would be happy to make those corrections.

Reviewer 3 Report

Comments and Suggestions for Authors

The authors have revised the manuscript. No issues detected.  

Author Response

Comment:

The authors have revised the manuscript. No issues detected.  

Response:

Thank you for your valuable feedback. We're glad that the revisions have addressed all concerns and that no further issues were detected. We appreciate your time and consideration in reviewing our manuscript.

Round 3

Reviewer 1 Report

Comments and Suggestions for Authors

I have no questions!