Design and Operating-Parameter Optimization of a Precision Seeder for Chinese Yam Based on Automatic Seed Distribution and Chain-Driven Metering

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Reviewer's Comments

I have carefully reviewed the manuscript titled "Design and Operating-Parameter Optimization of a Precision Seeder for Chinese Yam Based on Automatic Seed Distribution and Chain-Driven Metering" and would like to express my gratitude to the editorial department for the opportunity to review this work.

The manuscript addresses the practical problems of high labor demand, low operating efficiency, and insufficient seeding uniformity in Chinese yam planting. The authors designed a precision seeder integrating an automatic seed distribution device and a chain-driven metering system, and evaluated its performance through theoretical analysis, single-factor tests, response surface optimization, bench verification, and field validation. The research topic is relevant to agricultural mechanization, and the proposed device has clear engineering value for the mechanized planting of elongated tuber crops. Overall, the study is meaningful and potentially publishable after moderate revision.

1. The novelty and contribution of the study should be stated more clearly. The introduction reviews related equipment for potato, sugarcane, cassava, and yam planting, but the specific differences between the present machine and existing tuber-crop seeders are not sufficiently highlighted. It is recommended that the authors explicitly summarize the main contributions, such as the automatic seed distribution scheme for elongated Chinese yam seed segments, the chain-driven metering structure, and the optimization workflow combining material-parameter measurement, mechanism analysis, response surface optimization, and field validation.
2. The equations and theoretical analysis need careful checking and improvement. Some formulas in the manuscript appear incomplete or are not displayed properly. The authors should ensure that all formulas, equation numbers, variables, and units are complete and consistent. In addition, the explanations before and after the equations should be strengthened to clarify how the seed-box slope angle, seed-dropping height, and operating speed are theoretically related to seed-picking stability, seed-dropping motion, and plant-spacing control.
3. It is suggested that the author add simulation analysis and calculation of ‘the Automatic Seed Distribution Device and Chain-Driven Metering System’.
4. More information should be provided on the experimental design and statistical analysis. The manuscript should clearly state the number of replications, the number of evaluated intervals or seed segments in each test, the data-processing method, and the statistical software used. For the response surface analysis, it is suggested to provide the regression models, ANOVA results, model significance, lack-of-fit test, and determination coefficients, or at least the key statistical indicators needed to evaluate the reliability of the optimization results.
5. 5. It is suggested that the author calibrate the material characteristics of hemp seeds and establish the EDEM-ADAMS coupled simulation model.
6. The description of operating speed should be unified. In the technical specifications, the operating speed is given as 1.0-3.6 km h-1, whereas the optimized operating speed used in the response surface test and validation is 0.20 m s-1. Since these two values are not consistent after unit conversion, the authors should clarify whether the former refers to the general adjustable travel-speed range of the whole machine and the latter refers to the tested speed for precision metering. It is recommended to revise the table or add an explanation in the text to distinguish the design speed range, tested speed range, and recommended optimized speed.
7. 7. The field validation section should be supplemented with more experimental details. The authors are advised to describe the test site, soil condition, tractor model or matched power, seed-segment specification, number of replications, statistical method, and operation procedure. These details will improve the repeatability and credibility of the field validation results.
8. 8. The applicable scope and limitations of the current results should be stated more clearly. The validation appears to be conducted under a specific seed-segment size, cultivar, and field condition. It is recommended that the authors add a brief discussion indicating that further tests under different soil types, seed-segment sizes, and higher operating speeds are still needed before large-scale application.
9. 9. There is repeated text in the response surface optimization section, especially in the description of the predicted optimum. The repeated sentences should be removed, and the discussion should be condensed to improve readability.
10. 10. The figures and tables should be standardized. The unit format, capitalization, italic variables, and symbols should be checked throughout the manuscript. The response surface plots should be presented with higher resolution, and the captions should clearly indicate the response indicators and the fixed levels of the other factors.
11. 11. The terminology of the evaluation indicators should be consistent throughout the manuscript. Terms such as "qualified-seeding index", "multiple-seeding index", and "missed-seeding index" should be used uniformly in the abstract, methods, results, tables, and conclusions.
12. 12. The conclusions should be slightly condensed and more closely linked to the quantitative results. It is suggested that the authors clearly state the optimized parameter combination and the corresponding bench and field validation values, and avoid overly general claims that are not directly supported by the reported indicators.
13. 13. The English language and technical expression require further polishing. Some sentences are understandable but could be made more concise and precise. In particular, technical terms, units, and descriptions of mechanical structure and experimental procedures should be carefully edited by the authors.
14. There are many non-standard words in the paper. For example, in the P2, line 43,’operat-ing’; line44, ‘optimiza-tion’; in the P6, line 17, ‘re-sponse’; in the P7, line 19, ‘ad-justed’; in the P9, line 20, ‘condi-tion’; ……

Overall Evaluation: This manuscript provides a valuable contribution to the field of agricultural machinery, especially for the mechanized precision planting of Chinese yam and other elongated tuber crops. The research route is generally complete, and the proposed prototype shows promising performance in bench and field tests. However, several issues regarding equation presentation, statistical details, parameter consistency, field-test description, and language expression should be addressed. With appropriate moderate revisions, the paper has the potential to be suitable for publication.

Author Response

Comment 1:
The novelty and contribution of the study should be stated more clearly. The introduction reviews related equipment for potato, sugarcane, cassava, and yam planting, but the specific differences between the present machine and existing tuber-crop seeders are not sufficiently highlighted. It is recommended that the authors explicitly summarize the main contributions, such as the automatic seed distribution scheme for elongated Chinese yam seed segments, the chain-driven metering structure, and the optimization workflow combining material-parameter measurement, mechanism analysis, response surface optimization, and field validation.

Response 1:
Thank you for this helpful comment. We have revised the Introduction and Section 3.4 to clarify the novelty and contribution of the study. In the revised manuscript, we explicitly state that the proposed seeder is designed for short, soft, irregular, and elongated Chinese yam seed segments, which require ordered seed supply, constrained conveying, and stable oriented dropping. We also summarized the main contributions, including the automatic seed distribution scheme, the chain-driven metering structure, and the optimization workflow combining material-parameter measurement, mechanism analysis, response surface optimization, bench verification, and field validation. These revisions can be found in the last paragraph of the Introduction and in Section 3.4.

Comment 2:
The equations and theoretical analysis need careful checking and improvement. Some formulas in the manuscript appear incomplete or are not displayed properly. The authors should ensure that all formulas, equation numbers, variables, and units are complete and consistent. In addition, the explanations before and after the equations should be strengthened to clarify how the seed-box slope angle, seed-dropping height, and operating speed are theoretically related to seed-picking stability, seed-dropping motion, and plant-spacing control.

Response 2:
Thank you for pointing this out. We carefully checked and revised all equations, equation numbers, variables, and units in the manuscript. The formulas related to the seed-layer stress model, sprocket conveying condition, seed-dropping trajectory, plant-spacing equation, and response surface regression models were rechecked for completeness and consistency. We also strengthened the explanations before and after the equations to clarify how the seed-box slope angle, seed-dropping height, and operating speed are related to seed-picking stability, seed-dropping motion, and plant-spacing control. These changes can be found mainly in Sections 2.3, 2.4, and 3.2.

Comment 3:
It is suggested that the author add simulation analysis and calculation of the Automatic Seed Distribution Device and Chain-Driven Metering System.

Response 3:
Thank you for this suggestion. In the revised manuscript, we strengthened the theoretical calculation and mechanism analysis of the automatic seed distribution device and the chain-driven metering system. Specifically, we added and improved the seed-layer stress model, sprocket conveying stability condition, seed-dropping trajectory equation, and theoretical plant-spacing equation. These analyses were used to explain the selection of the seed-box slope angle, seed-dropping height, and operating speed. Since the focus of the present study is prototype design, bench verification, and field validation, a full coupled simulation model was not included in this revision. We have added this as a direction for future work.

Comment 4:
More information should be provided on the experimental design and statistical analysis. The manuscript should clearly state the number of replications, the number of evaluated intervals or seed segments in each test, the data-processing method, and the statistical software used. For the response surface analysis, it is suggested to provide the regression models, ANOVA results, model significance, lack-of-fit test, and determination coefficients, or at least the key statistical indicators needed to evaluate the reliability of the optimization results.

Response 4:
Thank you for this comment. We have supplemented the experimental design and statistical analysis in the revised manuscript. The single-factor tests were repeated three times at each factor level. The evaluation indicators were defined using the qualified-seeding index, multiple-seeding index, and missed-seeding index, and the calculation formulas were provided. The statistical analysis was described using one-way analysis of variance and Fisher’s F-test, with p < 0.05 considered significant and p < 0.01 considered highly significant. For the response surface analysis, we added the coded regression models, ANOVA results, model p-values, lack-of-fit p-values, determination coefficients, adjusted determination coefficients, and significant terms. These revisions can be found in Sections 2.4 and 3.2, especially Table 6.

Comment 5:
It is suggested that the author calibrate the material characteristics of hemp seeds and establish the EDEM-ADAMS coupled simulation model.

Response 5:
Thank you for the suggestion. We believe that the intended material is Chinese yam seed segments rather than hemp seeds. In the revised manuscript, we measured and summarized the material characteristics of Chinese yam seed segments, including geometric parameters, density, moisture content, intrinsic mechanical parameters, and seed–seed/seed–steel contact parameters. The corresponding standard deviations and coefficients of variation were also added to improve the objectivity of the material description. These results are presented in Section 2.1 and Table 2. A coupled EDEM-ADAMS simulation model was not established in the present revision because the study focuses on theoretical calculation, physical prototype design, bench verification, and field validation. Coupled simulation will be considered in future work.

Comment 6:
The description of operating speed should be unified. In the technical specifications, the operating speed is given as 1.0–3.6 km h−1, whereas the optimized operating speed used in the response surface test and validation is 0.20 m s−1. Since these two values are not consistent after unit conversion, the authors should clarify whether the former refers to the general adjustable travel-speed range of the whole machine and the latter refers to the tested speed for precision metering. It is recommended to revise the table or add an explanation in the text to distinguish the design speed range, tested speed range, and recommended optimized speed.

Response 6:
Thank you for pointing this out. We have clarified the description of operating speed in the revised manuscript. The operating speed in the technical specifications refers to the general adjustable travel-speed range of the whole machine, whereas the response surface test used a lower precision-metering speed range for parameter optimization. The optimized operating speed was 0.20 m s−1 under the tested conditions. We revised the relevant table and text to distinguish the design speed range, tested speed range, and recommended optimized speed.

Comment 7:
The field validation section should be supplemented with more experimental details. The authors are advised to describe the test site, soil condition, tractor model or matched power, seed-segment specification, number of replications, statistical method, and operation procedure. These details will improve the repeatability and credibility of the field validation results.

Response 7:
Thank you for this comment. We have supplemented the field validation details in the revised manuscript. The test site, soil condition, tractor model, seed-segment source and specification, seed amount, operation procedure, and recording method were added. Specifically, the field validation was conducted at the experimental base of Hebei Nonghaha Machinery Group Co., Ltd.; the soil was loam with a moisture content of 18–22% and a soil firmness of 1.2–1.5 MPa; the prototype was matched with an SD3004 tractor; approximately 20 kg of seed segments were prepared, with individual segment mass controlled at 30–50 g. Six validation runs were completed, and video recording was used to identify multiple and missed seeding and to cross-check the field measurements. These revisions can be found in Sections 2.4 and 3.3.

Comment 8:
The applicable scope and limitations of the current results should be stated more clearly. The validation appears to be conducted under a specific seed-segment size, cultivar, and field condition. It is recommended that the authors add a brief discussion indicating that further tests under different soil types, seed-segment sizes, and higher operating speeds are still needed before large-scale application.

Response 8:
Thank you for the suggestion. We have added a discussion of the applicable scope and limitations of the current results. The revised manuscript clarifies that the validation was conducted using a specific cultivar, seed-segment size range, and field condition. We also stated that further adaptability tests under different cultivars, seed-segment sizes, soil types, and higher operating speeds should be conducted before large-scale application. These revisions can be found in Sections 3.4 and 4.

Comment 9:
There is repeated text in the response surface optimization section, especially in the description of the predicted optimum. The repeated sentences should be removed, and the discussion should be condensed to improve readability.

Response 9:
Thank you for this comment. We revised Section 3.2 to remove repeated descriptions of the predicted optimum and condensed the discussion of the response surface optimization. The revised section now presents the optimization workflow, regression models, ANOVA summary, and predicted optimum in a clearer order. The previous repeated statements were removed to improve readability.

Comment 10:
The figures and tables should be standardized. The unit format, capitalization, italic variables, and symbols should be checked throughout the manuscript. The response surface plots should be presented with higher resolution, and the captions should clearly indicate the response indicators and the fixed levels of the other factors.

Response 10:
Thank you for pointing this out. We checked and standardized the figures, tables, units, capitalization, variables, and symbols throughout the manuscript. Unit expressions such as kg m−3, km h−1, and m s−1 were unified. Figures were centered according to the journal template requirements. The response surface plots were replaced with clearer versions, and the captions were revised to indicate the corresponding response indicators and parameter interactions. These changes can be found in Figures 1–7 and Tables 1–7.

Comment 11:
The terminology of the evaluation indicators should be consistent throughout the manuscript. Terms such as “qualified-seeding index”, “multiple-seeding index”, and “missed-seeding index” should be used uniformly in the abstract, methods, results, tables, and conclusions.

Response 11:
Thank you for the comment. We checked the terminology of the evaluation indicators throughout the manuscript. The terms “qualified-seeding index”, “multiple-seeding index”, and “missed-seeding index” are now used consistently in the Abstract, Methods, Results, tables, and Conclusions.

Comment 12:
The conclusions should be slightly condensed and more closely linked to the quantitative results. It is suggested that the authors clearly state the optimized parameter combination and the corresponding bench and field validation values, and avoid overly general claims that are not directly supported by the reported indicators.

Response 12:
Thank you for this suggestion. We revised and condensed the Conclusions to make them more closely linked to the quantitative results. The optimized parameter combination is now clearly stated as an operating speed of 0.20 m s−1, a seed-dropping height of 0.14 m, and a seed-box slope angle of 26.18°. Under the rounded validation setting of 0.20 m s−1, 0.14 m, and 26°, six field validation runs produced mean qualified-seeding, multiple-seeding, and missed-seeding indices of 86.16%, 5.13%, and 8.71%, respectively. General claims not directly supported by the reported indicators were removed or revised.

Comment 13:
The English language and technical expression require further polishing. Some sentences are understandable but could be made more concise and precise. In particular, technical terms, units, and descriptions of mechanical structure and experimental procedures should be carefully edited by the authors.

Response 13:
Thank you for the comment. We carefully polished the English language and technical expressions throughout the manuscript. The descriptions of the mechanical structure, working principle, experimental procedure, statistical analysis, and validation results were revised for clarity and consistency. Technical terms and units were also checked and standardized throughout the manuscript.

Comment 14:
There are many non-standard words in the paper. For example, in the P2, line 43, “operat-ing”; line 44, “optimiza-tion”; in the P6, line 17, “re-sponse”; in the P7, line 19, “ad-justed”; in the P9, line 20, “condi-tion”; etc.

Response 14:
Thank you for pointing this out. We carefully checked the entire manuscript and removed inappropriate hyphenation caused by formatting or line breaking. Words such as “operating”, “optimization”, “response”, “adjusted”, “condition”, “requirement”, “balanced”, “direction”, and “attributed” were corrected throughout the manuscript. We retained hyphens only in necessary compound technical terms, such as “chain-driven”, “seed-metering”, “seed-dropping”, “qualified-seeding”, “multiple-seeding”, and “missed-seeding”.

Reviewer 2 Report

Comments and Suggestions for Authors

This peer-reviewed article addresses a highly relevant practical issue in modern agricultural technology, which lies in increasing mechanization during Chinese Yam sowing. The authors propose a design that differs from existing designs by combining an automatic distribution device with a chain-type sowing machine. The work successfully combines theoretical and experimental research. However, to improve the overall quality of the article, I recommend that the authors take the following comments into account and address them:

1. I recommend reducing the volume of well-known facts in the abstract, particularly in the first two sentences. The abstract should concisely summarise the specific findings of this article.
2. It is recommended that the first paragraph of the introduction be supplemented with quantitative statistical data (of an economic, social, technical or other nature) confirming the importance and relevance of the research.
3. The overview of known solutions provided in the introduction should be supplemented by a more detailed analysis and a summary of their technical and functional characteristics, preferably including quantitative assessments. It is also recommended to expand this analysis by reviewing known automated seed distribution devices specifically designed for objects geometrically similar to the Chinese Yam. This will allow for a more objective assessment of the scientific novelty and practical value of the device developed by the authors.
4. From the point of view of the objectivity of the estimates of the geometric and physical parameters given in Table 1, these should be supplemented with estimates of the standard deviation or coefficient of variation, as the paragraph above states that these are average estimates. It would also be appropriate, from a statistical perspective, to present a distribution diagram of these indicators.
5. In subsection 2.3, the authors describe a stress model within the seed layer to substantiate the angle of inclination of the seed box, based, amongst other things, on differential calculations. However, it would be appropriate to provide information on how exactly the final resultant grip stress is integrated into the optimization criteria. This would enhance the objectivity of the model and the reproducibility of the results.
6. The quality of Figure 5 needs to be significantly improved; at present, this diagram is illegible and uninformative.
7. The numerical values of the coefficients in equation (11) are missing from the text of the article. Without these, it is impossible to assess the statistical significance of the higher-order components. Furthermore, any assertion regarding their significance (their inclusion in the computational model) must be based on standard approaches, such as Fisher’s criterion.
8. The conditions under which the experimental tests of the developed device were carried out should be described in greater detail: over what period were they conducted? How many sets of results were obtained? How were they analyzed? What destabilizing factors were identified, and how were these subsequently taken into account?
9. In their current form, the conclusions of the paper resemble a technical report rather than a scientific paper. The authors are advised to clarify the scientific novelty of the results obtained.

Author Response

Comment 1:
I recommend reducing the volume of well-known facts in the abstract, particularly in the first two sentences. The abstract should concisely summarise the specific findings of this article.

Response 1:
Thank you for this suggestion. We have revised the Abstract by reducing general background statements and emphasizing the specific findings of this study. The revised Abstract now focuses on the developed precision seeder, the measured seed segment properties, the theoretical models, the optimized parameter combination, and the field validation results. The optimized parameters and corresponding performance indices are now clearly stated: an operating speed of 0.20 m s−1, a seed-dropping height of 0.14 m, and a seed-box slope angle of 26.18°, with predicted qualified-seeding, multiple-seeding, and missed-seeding indices of 86.45%, 5.16%, and 8.40%, respectively. Field validation produced mean values of 86.16%, 5.13%, and 8.71%, respectively.

Comment 2:
It is recommended that the first paragraph of the introduction be supplemented with quantitative statistical data of an economic, social, technical, or other nature confirming the importance and relevance of the research.

Response 2:
Thank you for this comment. We have supplemented the first paragraph of the Introduction with quantitative production data to clarify the importance of the research. The revised manuscript states that China is one of the major global production areas for yam, with annual yam output remaining at approximately 10 million t in recent years and reaching 11.013 million t in 2024. The main production regions, including Jiangsu, Zhejiang, Hebei, Henan, Shandong, and Guangxi, are also listed. These data strengthen the background and relevance of developing mechanized precision seeding technology for Chinese yam.

Comment 3:
The overview of known solutions provided in the introduction should be supplemented by a more detailed analysis and a summary of their technical and functional characteristics, preferably including quantitative assessments. It is also recommended to expand this analysis by reviewing known automated seed distribution devices specifically designed for objects geometrically similar to the Chinese Yam. This will allow for a more objective assessment of the scientific novelty and practical value of the device developed by the authors.

Response 3:
Thank you for this helpful suggestion. We have substantially revised the Introduction and added a technical comparison table to summarize related seed-metering and seed-distribution devices. The revised manuscript now compares yam minisett planters, sugarcane and cassava stem-segment planters, potato and cut-potato precision metering devices, existing domestic Chinese-yam machinery, and chain-based metering devices for irregular materials. Their typical mechanisms, technical or functional characteristics, limitations for Chinese yam seed segments, and references are summarized. We also added a “This study” row to clarify that the proposed device integrates automatic seed distribution and chain-driven metering for ordered seed supply, constrained conveying, oriented dropping, and operating-parameter optimization. This revision more clearly highlights the novelty and practical value of the proposed device.

Comment 4:
From the point of view of the objectivity of the estimates of the geometric and physical parameters given in Table 1, these should be supplemented with estimates of the standard deviation or coefficient of variation, as the paragraph above states that these are average estimates. It would also be appropriate, from a statistical perspective, to present a distribution diagram of these indicators.

Response 4:
Thank you for this comment. We have revised the material-parameter table by adding the standard deviation and coefficient of variation for each measured parameter. The revised table now reports the mean value, SD, and CV for the geometric, physical, mechanical, and contact parameters of Chinese yam seed segments. A note was also added to clarify that the SD has the same unit as the corresponding mean value, whereas CV is dimensionless. These additions improve the objectivity and statistical description of the measured material properties. Because the revised table already provides both SD and CV for each parameter, and to keep the manuscript concise, the distribution information is presented in tabular statistical form rather than as additional distribution diagrams.

Comment 5:
In subsection 2.3, the authors describe a stress model within the seed layer to substantiate the angle of inclination of the seed box, based, amongst other things, on differential calculations. However, it would be appropriate to provide information on how exactly the final resultant grip stress is integrated into the optimization criteria. This would enhance the objectivity of the model and the reproducibility of the results.

Response 5:
Thank you for this important comment. We have revised Section 2.3 to clarify how the calculated resultant seed-picking stress was integrated into the optimization workflow. In the revised manuscript, the resultant seed-picking stress is expressed as σp(θ), and it is used as a physical constraint rather than as an independent response variable. Specifically, the tested seed-box slope angle was limited to the range in which σp(θ) was sufficient to maintain continuous seed supply but not high enough to cause excessive squeezing or mechanical damage according to the compression and shear tests. Within this physically feasible range, the response surface optimization was used to maximize the qualified-seeding index and minimize the multiple- and missed-seeding indices. This revision improves the reproducibility and objectivity of the optimization process.

Comment 6:
The quality of Figure 5 needs to be significantly improved; at present, this diagram is illegible and uninformative.

Response 6:
Thank you for pointing this out. We have replaced and improved Figure 5. The revised figure more clearly shows the seed-guiding and seed-dropping processes, including the seed box, guiding channel, dropping channel, seed-cup motion, seed-dropping height, and plant spacing. The figure caption was also revised to clearly identify the two subfigures: the seed-guiding process and the seed-dropping process.

Comment 7:
The numerical values of the coefficients in equation (11) are missing from the text of the article. Without these, it is impossible to assess the statistical significance of the higher-order components. Furthermore, any assertion regarding their significance, namely their inclusion in the computational model, must be based on standard approaches, such as Fisher’s criterion.

Response 7:
Thank you for this comment. We have revised Section 3.2 by adding the fitted coded regression equations with the numerical coefficients for the qualified-seeding index, multiple-seeding index, and missed-seeding index. The regression models are now presented directly in the text. In addition, the ANOVA and model-fit summary table was added, including model F-values, model p-values, lack-of-fit p-values, R², adjusted R², CV, and significant terms. Fisher’s F-test was used to evaluate the significance of the regression models and individual terms. Terms with p < 0.05 were considered significant and retained in the final equations. This revision provides the statistical basis for retaining the higher-order and interaction terms in the models.

Comment 8:
The conditions under which the experimental tests of the developed device were carried out should be described in greater detail: over what period were they conducted? How many sets of results were obtained? How were they analyzed? What destabilizing factors were identified, and how were these subsequently taken into account?

Response 8:
Thank you for the suggestion. We have supplemented the experimental and field validation details in the revised manuscript. The test site, soil condition, tractor model, seed segment source and specification, seed amount, operation procedure, and recording method were added. The field validation was conducted at the experimental base of Hebei Nonghaha Machinery Group Co., Ltd.; the soil was loam with a moisture content of 18–22% and a soil firmness of 1.2–1.5 MPa; the prototype was matched with an SD3004 tractor; approximately 20 kg of seed segments were prepared, with individual segment mass controlled at 30–50 g. Six field validation runs were completed. The measured results were analyzed by calculating the mean values of the qualified-seeding, multiple-seeding, and missed-seeding indices. The identified destabilizing factors included seed segment size dispersion, slight field-surface unevenness, machine vibration, and soil disturbance during seed landing. These factors were discussed in Section 3.3 and were further considered as directions for future improvement, including seed segment grading, posture control, and online monitoring of missed and multiple seeding.

Comment 9:
In their current form, the conclusions of the paper resemble a technical report rather than a scientific paper. The authors are advised to clarify the scientific novelty of the results obtained.

Response 9:
Thank you for this valuable comment. We have revised and condensed the Conclusions to make them more closely linked to the scientific findings and quantitative results. The revised Conclusions now clearly state the optimized parameter combination and the corresponding field validation results. We also clarified the scientific novelty of the study: a dedicated seed-metering solution was developed for short, soft, irregular, and elongated Chinese yam seed segments. Compared with existing tuber or stem-segment metering devices, the proposed machine combines automatic ordered seed supply, constrained chain conveying, and oriented dropping, and establishes an optimization workflow involving material-parameter measurement, mechanism analysis, single-factor screening, response surface optimization, bench verification, and field validation.

Reviewer 3 Report

Comments and Suggestions for Authors

•     Summary

The manuscript presents the design and development of a precision seeder for Chinese yam based on automatic seed distribution and a chain-driven metering system. The study combines machine design, single-factor testing, response surface methodology, bench verification, and field validation to optimize seeding performance using qualified-seeding, multiple-seeding, and missed-seeding indices for evaluation. The work addresses an important mechanization challenge in Chinese yam cultivation and attempts to improve planting efficiency.

•     Major issues

-Line 55 states that the seed segments 55 have a large length-to-diameter ratio and irregular shape. Subsequently, under sub-section 2.3, do the equations capture the variability in seed geometry or assume idealized geometry? Are there any assumptions made in the study?

-The manuscript lacks sufficient detail regarding the experimental setup and replication. Suggest that the authors provide more information about the number of replicates, sample size per treatment, randomization procedures, and statistical assumptions, if any.

-Under sub-section 2.4, field validation was carried out under only one soil type, environmental condition, and soil firmness (loam soil, 18–22% moisture content, and 1.2–1.5 MPa). Testing under multiple conditions would strengthen the robustness of the study.

-The manuscript states the results from the single-factor tests were significant, but no detailed ANOVA tables, regression coefficients, p-values, or R² values are provided. I suggest that the authors include them for the assessment of the optimized parameters.

-Suggest that authors include comparative benchmarks with other studies and existing planters to better demonstrate the novelty and practical value of the proposed system.

-The authors should also discuss whether the performance level (qualified-seeding index of 86.16%) is acceptable for Chinese yam production and compare with existing planters.

-Section 3.4 - Authors should cite the “published studies” and give more details (metrics, performance) comparing them to the current study rather than just giving statements.

-What challenges were faced in the study?

•     Minor issues

The entire manuscript needs revision. Citations are in superscript and should be corrected. For example, line 48 - scale and standardized production[1,2].

Line 83 -  optimiza-tion to optimization

Line 92 - 1003 kg m−3 to 1003 kg m−3

Line 110 -  center figure 1 and all the subsequent figures

Line 181 - require-ment to requirement

Line 184 - consistency in using “seed-segment” or “seed segment” throughout the manuscript

Line 208 - ad-justed

Line 265 - 0.20 m s−1

Line 268,279, 286 - bal-anced , direc-tion, at-tributed. Many words have hyphens where they do not belong. Suggest that authors check the whole manuscript.

Author Response

Comment 1:
Line 55 states that the seed segments 55 have a large length-to-diameter ratio and irregular shape. Subsequently, under sub-section 2.3, do the equations capture the variability in seed geometry or assume idealized geometry? Are there any assumptions made in the study?

Response 1:
We added a description of the assumptions used in the theoretical model in Section 2.3. The revised manuscript now clarifies that the theoretical analysis was based on equivalent geometric parameters of the seed segments. Since Chinese yam seed segments are irregular biological materials, their geometric variability was not directly introduced into each equation. Instead, the measured mean values and dispersion indicators in Table 2 were used to determine representative structural parameters, and the effects of seed segment variability were further evaluated through bench verification and field validation.

Comment 2:
The manuscript lacks sufficient detail regarding the experimental setup and replication. Suggest that the authors provide more information about the number of replicates, sample size per treatment, randomization procedures, and statistical assumptions, if any.

Response 2:
We supplemented the experimental-design and statistical-analysis description in Section 2.4. The revised manuscript now states that single-factor tests were repeated three times at each factor level, that evaluated intervals were recorded after the seed-metering system reached stable operation, and that one-way ANOVA and Fisher’s F-test were used to evaluate factor effects and model-term significance. We also clarified the statistical assumptions and explained that the treatment order was adjusted between repeated runs where possible to reduce systematic bias.

Comment 3:
Under sub-section 2.4, field validation was carried out under only one soil type, environmental condition, and soil firmness (loam soil, 18–22% moisture content, and 1.2–1.5 MPa). Testing under multiple conditions would strengthen the robustness of the study.

Response 3:
We further discussed the limitation of field validation under a single soil condition. The revised manuscript now states that the field validation was conducted under loam soil with a moisture content of 18–22% and a soil firmness of 1.2–1.5 MPa, and that the robustness of the optimized parameters still needs to be verified under different soil textures, moisture levels, field surface conditions, and higher operating speeds.

Comment 4:
The manuscript states the results from the single-factor tests were significant, but no detailed ANOVA tables, regression coefficients, p-values, or R² values are provided. I suggest that the authors include them for the assessment of the optimized parameters.

Response 4:
We strengthened the statistical reporting. A single-factor ANOVA summary table including F-values and p-values was retained, and the response surface section now provides fitted regression models, numerical regression coefficients, model p-values, lack-of-fit p-values, R², adjusted R², CV, and significant terms based on Fisher’s F-test.

Comment 5:
Suggest that authors include comparative benchmarks with other studies and existing planters to better demonstrate the novelty and practical value of the proposed system.

Response 5:
We revised Section 3.4 to provide a clearer comparison with published studies and existing planters. Quantitative benchmarks from related studies were added, including structural safety indices for a yam minisett planter, a seed-filling qualification index for a cassava seeding mechanism, and qualified-, missed-, and multiple-seeding rates for a potato precision seed-metering device. We also clarified that although the field qualified-seeding index of 86.16% is lower than that reported for some potato and cassava seed-metering devices, it is practically meaningful for Chinese yam planting because the target seed material is softer, more elongated, more irregular, and more posture-sensitive.

Comment 6:
The authors should also discuss whether the performance level (qualified-seeding index of 86.16%) is acceptable for Chinese yam production and compare with existing planters.

Response 6:
We added a clearer discussion of the challenges encountered in the study, including seed segment size dispersion, irregular surface morphology, unstable posture during seed entry and dropping, variation in seed-supply pressure caused by the seed-box slope angle, machine vibration, slight field-surface unevenness, and soil disturbance during seed landing.

Comment 7:
Section 3.4 - Authors should cite the “published studies” and give more details (metrics, performance) comparing them to the current study rather than just giving statements.

Response 7:
Thank you for the suggestion. We have substantially revised Section 3.4 by adding comparisons with published studies and including quantitative performance metrics. Specifically, we compared the present study with a yam minisett planter that reported a hopper deformation of 0.442 mm and a ridger-bottom stress of 9.18 MPa, a pre-cut cassava seeding mechanism with a seed-filling qualification index of 94.13%, and a potato precision seed-metering device with a field qualified-seeding rate of 91.54%, a miss-seeding rate of 3.08%, and a multi-seeding rate of 5.38%. In comparison, the present Chinese yam seeder achieved a field qualified-seeding index of 86.16%, a multiple-seeding index of 5.13%, and a missed-seeding index of 8.71%. These revisions provide a clearer comparison between the present device and published studies.

Comment 8:
What challenges were faced in the study?

Response 8:
Thank you for this question. We have added a discussion of the main challenges encountered in this study in Section 3.4. The main challenges included seed segment size dispersion, irregular surface morphology, unstable posture during seed entry and dropping, variation in seed-supply pressure caused by the seed-box slope angle, and field disturbances such as slight surface unevenness, machine vibration, and soil disturbance during seed landing. These factors contributed to the remaining missed- and multiple-seeding errors and indicate that future prototypes should further improve seed segment grading, seed-cup adaptability, posture control, and online monitoring of missed and multiple seeding.

Comment 9:
Line 83 - optimiza-tion to optimization.

Response 9:
Thank you for pointing this out. We have corrected “optimiza-tion” to “optimization” in the revised manuscript. We also checked the whole manuscript and removed similar inappropriate hyphenation caused by formatting or line breaking.

Comment 10:
Line 92 - 1003 kg m−3 to 1003 kg m−3.

Response 10:
Thank you for the comment. We have standardized the unit expression in Table 2 and throughout the manuscript. The density unit is now presented as “kg m−3”, and similar unit expressions such as “m s−1” and “km h−1” were also checked and unified.

Comment 11:
Line 110 - center Figure 1 and all the subsequent figures.

Response 11:
Thank you for pointing this out. We have checked Figure 1 and all subsequent figures and adjusted their layout to center alignment according to the manuscript template requirements.

Comment 12:
Line 181 - require-ment to requirement.

Response 12:
Thank you for pointing this out. We have corrected “require-ment” to “requirement” in the revised manuscript. Similar incorrectly hyphenated words were also checked and corrected throughout the manuscript.

Comment 13:
Line 184 - consistency in using “seed-segment” or “seed segment” throughout the manuscript.

Response 13:
Thank you for this comment. We have checked the terminology throughout the manuscript. In the revised version, “seed segment” is used consistently when referring to the Chinese yam planting material. Hyphenated forms are retained only in necessary compound technical terms, such as “seed-box slope angle”, “seed-cup structure”, “seed-metering system”, and “seed-dropping height”.

Comment 14:
Line 208 - ad-justed.

Response 14:
Thank you for pointing this out. We have corrected “ad-justed” to “adjusted” in the revised manuscript and checked the whole manuscript for similar formatting-related hyphenation errors.

Comment 15:
Line 265 - 0.20 m s−1.

Response 15:
Thank you for the comment. We have checked and unified the speed unit format throughout the manuscript. The optimized operating speed is now consistently expressed as “0.20 m s−1” in the Abstract, Methods, Results, and Conclusions.

Comment 16:
Line 268, 279, 286 - bal-anced, direc-tion, at-tributed. Many words have hyphens where they do not belong. Suggest that authors check the whole manuscript.

Response 16:
Thank you for this helpful comment. We carefully checked the entire manuscript and removed inappropriate hyphenation caused by line breaking or formatting. Words such as “balanced”, “direction”, “attributed”, “optimization”, “requirement”, “adjusted”, “response”, and “condition” were corrected throughout the manuscript. We retained hyphens only in necessary technical compound terms, such as “chain-driven”, “seed-metering”, “seed-dropping”, “qualified-seeding”, “multiple-seeding”, and “missed-seeding”.

 

   

 

 

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

I have no comments.

Reviewer 3 Report

Comments and Suggestions for Authors

Comments addressed