Effect of Row Cleaner Operational Settings on Crop Residue Translocation in Strip-Tillage

Round  1

Reviewer 1 Report

General comment

This manuscript reports the effect of row cleaner’s operational features on the residue removal in strip tillage. The subject of study is of interest for efficient application of tillage machinery and its agronomic benefits. The study has been conducted in a scientific manner, the modelling approach has provided a good insight into the dynamic effect of design characteristic on functional effectiveness of row cleaners. The results have also been interpreted clearly. There are a couple of comments and concerns that I have mentioned in specific comments with more details to improve this manuscript.  

Specific comments

Title:

Line 2, I am not sure if “How” is necessary. If so, the sentence should end with a question mark. Moreover, “residue” can be used both as plural and singular form, there is no need for “-s” at the end, here and elswhere.

Abstract:

Line 13, What authors mean by “optimally”? please quantify or fefine.

Introduction

Lines 28-31, This statement does not reflect the entire story. In contrast to what is stated, no-tillage in general results in greater soil compaction than tilled systems, because of the obvious effect of soil manipulation and if no-till is not accompanied by ancillary biological regulators _e.g. cover cropping, crop rotation or organic additives, in most of the cases results in lower water infiltrability and permeability than tilled systems.

So, add another statement starting in line 31, mentioning that, the favorable soil physical and hydraulic condition in no-till systems highly depends on the incorporation of ancillary practices such as cover crops, rotational cropping and organic amendments and cite the following references:

Nouri, A., Lee, J., Yin, X., D Tyler, D., Jagadamma, S. and Arelli, P., 2018. Soil Physical Properties and Soybean Yield as Influenced by Long-Term Tillage Systems and Cover Cropping in the Midsouth USA. Sustainability, 10(12), p.4696.

Blanco-Canqui, H., Wienhold, B.J., Jin, V.L., Schmer, M.R. and Kibet, L.C., 2017. Long-term tillage impact on soil hydraulic properties. Soil and Tillage Research, 170, pp.38-42.

Wienhold, B.J. and Tanaka, D.L., 2000. Haying, tillage, and nitrogen fertilization influences on infiltration rates at a conservation reserve program site. Soil Science Society of America Journal, 64(1), pp.379-381.

Line 64, rephrase the statement for clarity.

Lines 84-87, the wording is confusing, the entire part should be revised for clarity.

Line 94, “on the adjacent tilled strip” may be a better alternative.

Line 96, Add two or three statements explaining the study objectices.

Material and Methods:

Line 98, Start this section with a title of “2. Material and Methods” before 2.1 subtitle.

Line 100, put comma after “classification”. What “it” refers to? Clarify.

Line 110, what was the soil textural class?  It is not clear if soil moisture content was measured as the average moisture at 0-20 cm or soil samples were directly collected at 20 cm.

Line 116, please revise as “clogging up the between discs space”

Line 159, Correct the “m.s^-1” as “m s^-1” here and elsewhere including the figures.

Line 160, “empirical model” or more specifically “multiple regression model”?

Lines 167-169, The words in this part seems to have different font size. “and statement of confidence were analyzed at” does not statistically make sense. Revise it as “the significance of model parameters was tested at the confidence interval of p < 0.01”.

Line 168, R-square is a coefficient of relation and is not an indicator of the strength of correlation as stated by author. Revise the statement for accuracy.

Results and Discussion

Line 175, in this equation and others, change the comma sign used as decimal indicator to point for all model coefficients. Please explain why this model and others include polynomial terms while the fittings in figures are all linear.  

Line 190, In this figure and others it is not clear how using experimental data derived from application of three rake angles, authors have fitted six rake angles. Please clarify. Also correct the unit in x-axis (remove multiplication sign).

Lines 245-247, This statement conflicts the statement in lines 180-182 which claims that “the driving speed does not affect the amount of removed plant residues”. Please clarify.

Comments for author File: Comments.docx

Author Response

Answers to comments:

General comment

This manuscript reports the effect of row cleaner’s operational features on the residue removal in strip tillage. The subject of study is of interest for efficient application of tillage machinery and its agronomic benefits. The study has been conducted in a scientific manner, the modelling approach has provided a good insight into the dynamic effect of design characteristic on functional effectiveness of row cleaners. The results have also been interpreted clearly. There are a couple of comments and concerns that I have mentioned in specific comments with more details to improve this manuscript. 

Specific comments

Title:

Comment: Line 2, I am not sure if “How” is necessary. If so, the sentence should end with a question mark. Moreover, “residue” can be used both as plural and singular form, there is no need for “-s” at the end, here and elswhere.

Response: Title was corrected. “Residues” changed to “residue”.

Abstract:

Comment: Line 13, What authors mean by “optimally”? please quantify or fefine.

Response: According to reviewer's comment it was defined.

Introduction

Comment: Lines 28-31, This statement does not reflect the entire story. In contrast to what is stated, no-tillage in general results in greater soil compaction than tilled systems, because of the obvious effect of soil manipulation and if no-till is not accompanied by ancillary biological regulators _e.g. cover cropping, crop rotation or organic additives, in most of the cases results in lower water infiltrability and permeability than tilled systems.

So, add another statement starting in line 31, mentioning that, the favorable soil physical and hydraulic condition in no-till systems highly depends on the incorporation of ancillary practices such as cover crops, rotational cropping and organic amendments and cite the following references:

Nouri, A., Lee, J., Yin, X., D Tyler, D., Jagadamma, S. and Arelli, P., 2018. Soil Physical Properties and Soybean Yield as Influenced by Long-Term Tillage Systems and Cover Cropping in the Midsouth USA. Sustainability, 10(12), p.4696.

Blanco-Canqui, H., Wienhold, B.J., Jin, V.L., Schmer, M.R. and Kibet, L.C., 2017. Long-term tillage impact on soil hydraulic properties. Soil and Tillage Research, 170, pp.38-42.

Wienhold, B.J. and Tanaka, D.L., 2000. Haying, tillage, and nitrogen fertilization influences on infiltration rates at a conservation reserve program site. Soil Science Society of America Journal, 64(1), pp.379-381.

Response: It was corrected according to reviewer's suggestion.

Comment: Line 64, rephrase the statement for clarity.

Response: Sentence was rephrased.

Comment: Lines 84-87, the wording is confusing, the entire part should be revised for clarity.

Response: It was revised.

Comment: Line 94, “on the adjacent tilled strip” may be a better alternative.

Response: It was corrected according to reviewer's suggestion.

Comment: Line 96, Add two or three statements explaining the study objectices.

Response: More information was added to the end of introduction.

Material and Methods:

Comment: Line 98, Start this section with a title of “2. Material and Methods” before 2.1 subtitle.

Response: According to reviewer's comment it was corrected.

Comment: Line 100, put comma after “classification”. What “it” refers to? Clarify.

Response: In response to comment, a comma placed in line 100, after word - “classification” and “it” was modified and further refined for a clearer understanding:

“According to the Köppen-Geiger climate classification, location of field experiment belongs to a humid continental climate region (Dfb) [43].”

Comment: Line 110, what was the soil textural class? It is not clear if soil moisture content was measured as the average moisture at 0-20 cm or soil samples were directly collected at 20 cm.

Response: For clearly understanding, relief – slightly wavy plain, the soil formed in the area of the bottom moraines or bottom glacial deposits, covered with limnoglacial sediments, deeply lukewarm soaked soil (Endohypogleyic-Eutric Planosol – PLe-gln-w).

Soil moisture content was measured as the average moisture at 0–20 cm.

Comment: Line 116, please revise as “clogging up the between discs space”

Response: It was corrected according to reviewer's suggestion.

Comment: Line 159, Correct the “m.s-1” as “m s-1” here and elsewhere including the figures.

Response: It was corrected.

Comment: Line 160, “empirical model” or more specifically “multiple regression model”?

Response: It was corrected according to reviewer's suggestion.

Comment: Lines 167-169, The words in this part seems to have different font size. “and statement of confidence were analyzed at” does not statistically make sense. Revise it as “the significance of model parameters was tested at the confidence interval of p < 0.01”.

Response: According to Rewiever‘s comment font size was corrected to the same in all text.

Statistical data analysis section was revised as “the significance of model parameters was tested at the confidence interval of p < 0.01”.

Comment: Line 168, R-square is a coefficient of relation and is not an indicator of the strength of correlation as stated by author. Revise the statement for accuracy.

Response: According to comment, Line 168 was revised from “R-square and its significance (P < 0.01) presented in order to show correlation between experimental and empirical results” to:

“R-square presented relation between experimental and empirical results.”

Results and Discussion

Comment: Line 175, in this equation and others, change the comma sign used as decimal indicator to point for all model coefficients. Please explain why this model and others include polynomial terms while the fittings in figures are all linear. 

Response: For clear understanding, 4 and 3 of 10 coefficients were found to be no significant. Therefore, regression equations were obtained using average of 6 and 7 coefficients (in figures) and model was written in polynomial term, because it was closer to the average values. 

Comment: Line 190, In this figure and others it is not clear how using experimental data derived from application of three rake angles, authors have fitted six rake angles. Please clarify. Also correct the unit in x-axis (remove multiplication sign).

Response: We carried out experimental research with three rake angles however we prognose results in theory with more rake angles (12.5, 17.5 and 20 degrees) than three using the three-factor experiment modelling method. The same with other data.

Comment: Lines 245-247, This statement conflicts the statement in lines 180-182 which claims that “the driving speed does not affect the amount of removed plant residues”. Please clarify.

Response: The driving speed does not affect the amount of removed plant residues however the driving speed has a major impact on the distance of removed plant residues from the strip.

Author Response File: Author Response.doc

Reviewer 2 Report

The paper reports on a worthy experiment.

The paper needs to define the crop residue more and show a picture of it.  Paper needs to confirm that amount of standing stuble on the site and the amount of residue spread on the site.  What whas the height of the standing stubble?

Next the equipment needs to be defined.

The gap between the discs needs to be defined as to where this was measured.

The rake angle needs to be defined.  It looks like the disc was vertical but just rotated in orientation to travel.  This is not a rake and but a slip angle.  Look at wheel/coulter definitions.

The movement of plant residue must be defined.  Show on a diagram the assumed width of clearing.  Show some photos also of a row before and after clearing.

It was mentioned a 10 m strip was examined.  Did you remove all of the residue for 10m?  How was it collected.  How did you decide what was in and out of the strip if the residue was over the boundary.

The paper must define what is distance of residue movement.  How was it measured? this needs to be added in clear manner.

The creation of a model is of little importance.  the more importance is to show some images and extremes of perforance.  Many fof the modelled data do not seem to match the measurements.

I encourage you to reevaluate the results in light of the defintions as try to show some physical meaning to the numbers you present in the results.  

Author Response

Answers to comments:

Comment: The paper needs to define the crop residue more and show a picture of it.  Paper needs to confirm that amount of standing stuble on the site and the amount of residue spread on the site.  What whas the height of the standing stubble?

Response: Height of the standing stubble was approximately 10 cm. Information about the residues provided in the sub-section 2.1.

Comment: Next the equipment needs to be defined. The gap between the discs needs to be defined as to where this was measured.

Response: Gap between row cleaner discs of standing parallel. According Reviewer comment was defined in the Abstract.

Comment: The rake angle needs to be defined.  It looks like the disc was vertical but just rotated in orientation to travel. This is not a rake and but a slip angle.  Look at wheel/coulter definitions.

Response: It is corrected according to reviewer's comment.

Comment: The movement of plant residue must be defined.  Show on a diagram the assumed width of clearing.  Show some photos also of a row before and after clearing. 

Response: It was corrected sub-section 2.3. Movement of plant residue was showed in Figure 3.

Comment: It was mentioned a 10 m strip was examined.  Did you remove all of the residue for 10m?  How was it collected.  How did you decide what was in and out of the strip if the residue was over the boundary.

Response: All residues were not remove. About residues collected was corrected and provide in the sub-section 2.3.

Comment: The paper must define what is distance of residue movement.  How was it measured? this needs to be added in clear manner.

Responce: Drawing is provided in the sub-section 2.2.

Comment:The creation of a model is of little importance.  the more importance is to show some images and extremes of perforance.  Many fof the modelled data do not seem to match the measurements.

Response: Modelled data is similar with the measurements. Difference between the experimental and empirical values was got with error on average approximately 12%.

Comment: I encourage you to reevaluate the results in light of the defintions as try to show some physical meaning to the numbers you present in the results.  

Response: According to the comment, at the end of the Results section we added practical meaning of our results.

Author Response File: Author Response.doc

Reviewer 3 Report

The paper addresses an important aspect of crop residue management in strip tillage. However, to qualify as a full length article, the article need to be improved as suggested below and marked in the attached e-copy. 1. The English need to be improved for a clear understanding of the contents of the article by the readers. 2. This paper did not attempt to design a row cleaner, rather studied the effect of row cleaner operational parameters on crop residue relocation. Therefore, title may be changed to “Effect of row cleaner operational settings on crop residue translocation in strip-tillage”. Accordingly, throughout the paper, the word ‘design’ should be replaced with an appropriate word(s) (e.g. settings, etc.) 3. Please format the Abstract with the following sub-sections: Background and significance of the research, objective(s), methodology employed (tools, techniques, treatments, data), key results, conclusion and recommendation 4. Introduction: Please explain the research gap and scope of this research more clearly (as residue handling by row cleaners has been studied previously).   5. Please define terms such as ‘performed optimally’. How to define/measure/quantify the optimum performance? 6. Better use standard terminologies. Example, “conservation tillage” instead of “non-ploughing tillage”. Please check all. 7. Past indefinite tense need to be used in literature review. 8. L39–40: Please clarify the sentence. 9. L55-56, please re-write the sentences clearly. 10. L64, please explain why “Row cleaners in the form of discs are the most commonly used”. 11. L90–96, please merge this section with the previous section (L61–69). 12. Please add a section 2.0 Materials and Methods before the sub-section 2.1 13. Table 1, better present as a chart/graph. 14. L106: The experiment should be conducted with naturally existing field residues after harvest. Why residues were chopped in 10 cm pieces and artificially spread over the soil? Please clarify. 15. Please provide detail of the instrument used (model, resolution, manufacturer, city) and the process of measurement. 16. L108: Provide variability of residue load (3700±???? kg ha-1) in the test plot. 17. L118: Please show the working depth in Fig. 1. 18. L123–126: Please justify the treatment levels. 19. L114–18: Please also add a description of the prime mover (tractor?) used and how the speeds were controlled and measured. 20. L123–126: Please add plot sizes used, statistical design followed and number of replications used. 21. L132–136: Procedure not clear. Please write the procedure clearly. Also, please add how the pre-test residue load was measured. 22. L 138: Please explain more clearly how distance of the removed plant residues was measured. A figure/drawing can be useful to clarify this. 23. L178: “plant residues increasing just slightly, on average approximately 3% ....” – please check it. Its more than 3% in Fig. 3a! 24. Please add an observation/comment on how much residues were entangled in to the row cleaner. How did it change due to speed, rake angle, gap? 25. Please remove the values (turn off ‘add data labels’) in all the Charts (Fig. 3a–5) 26. L179–182: Please explain the scientific reason(s) behind this. Please also explain the difference between the experimental and empirical values. 27. L184–187: Please explain the scientific reason behind this. Please also explain the difference between the experimental and empirical values. 28. L204–214: Please explain the scientific reason behind this. Please also explain the difference between the experimental and empirical values. 29. L231–232: Please clarify the sentence. 30. L233–235: Please explain the scientific reason behind this. Please also explain the difference between the experimental and empirical values.

Comments for author File: Comments.pdf

Author Response

Answers to comments:

Comment: 1. The English need to be improved for a clear understanding of the contents of the article by the readers.

Response: The English was improved.

Comment: 2. This paper did not attempt to design a row cleaner, rather studied the effect of row cleaner operational parameters on crop residue relocation. Therefore, title may be changed to “Effect of row cleaner operational settings on crop residue translocation in strip-tillage”. Accordingly, throughout the paper, the word ‘design’ should be replaced with an appropriate word(s) (e.g. settings, etc.).

Response: It is corrected according to reviewer's comment.

Comment: 3. Please format the Abstract with the following sub-sections: Background and significance of the research, objective(s), methodology employed (tools, techniques, treatments, data), key results, conclusion and recommendation.

Response: The Abstract is corrected according to reviewer's comment.

Comment: 4. Introduction: Please explain the research gap and scope of this research more clearly (as residue handling by row cleaners has been studied previously).

Response: Information was added in section 1. Introduction: This manuscript is continuation of the previously published article and completes all research results. Was performed comprehensive study of theoretical substantiation of the design of disc row cleaners for strip tillage and strip width, experiments of plant residues amount removal from the strip and distance of plant residue removal from the centre of the strip, the compilation of empirical models, and the comparative analysis of empirical and experimental results. Therefore our study was divided into two parts. First part was presented in the previous article, which described theoretical substantiation of strip width and interaction of disc row cleaner with the soil. Theoretical and experimental research results of influence of row cleaners technological parameters (slip angle, gap and diameter of row cleaner discs) on cleaned strip width were presented. Also, the influence of row cleaner technological parameters on the of plant residue removal distance was investigated and only experimental results were presented. The previous article concluded that in future studies needed to be considered the influence of row cleaners parameters and driving speed on amount of plant residues cleaned from the strip soil surface. Second part of the research presented in this paper, where described new experimental results which show the influence of row cleaner parameters on plant residue removal from the strip. According to the new experimental data of the amount of removed plant residues and to experimental data from previous paper (distance from the strip centre removed plant residue), we constructed the empirical models, which show a change in removed plant residue from the strip and the distance of the removed plant residue from the centre of the strip depending on the more technological parameters. The results of experimental studies of distance of plant residue removal were necessary to repeat in order to be able to compare it with the empirical model and to have complete view of the research performed. In the previous article was not possible to show it because of the different aim and its scope.

Comment: 5. Please define terms such as ‘performed optimally’. How to define/measure/quantify the optimum performance?

Response: The sentence was corrected. The results of the field experiments and empirical analysis showed that the amount and the distance of removed plant residues were best when the slip angle was 15°, the gap between the discs of row cleaner was 180 mm, and the driving speed was 2.5 m s^-1.

Comment: 6. Better use standard terminologies. Example, “conservation tillage” instead of “non-ploughing tillage”. Please check all.

Response: It is corrected according to reviewer's suggestion.

Comment: 7. Past indefinite tense need to be used in literature review.

Response: It was corrected according to reviewer's suggestion.

Comment: 8. L39–40: Please clarify the sentence.

Response: The sentence is corrected.

Comment:  9. L55-56, please re-write the sentences clearly.

Response: The first sentence was deleted because it is not informative. The second sentence was rewritten.

Comment: 10. L64, please explain why “Row cleaners in the form of discs are the most commonly used”.

Response: Row cleaners in the form of discs are the most commonly used because the discs are working without clogging with plant residues and discs are cleaning residue off a strips better.

Comment:  11. L90–96, please merge this section with the previous section (L61–69).

Response: It is corrected according to reviewer's suggestion.

Comment: 12. Please add a section 2.0 Materials and Methods before the sub-section 2.1

Response: It was corrected according to reviewer's comment.

Comment: 13. Table 1, better present as a chart/graph.

Response: Table 1 is presented as a graph.

Comment: 14. L106: The experiment should be conducted with naturally existing field residues after harvest. Why residues were chopped in 10 cm pieces and artificially spread over the soil? Please clarify.

Response: The sentence L106 is not clear, therefore it may mislead reader. The sentence L106 was deleted. Experiment was conducted with naturally existing field plant residues after harvest. Plant residues were chopped and spread with a rotating spreader mechanism of combine during harvesting process.

Comment: 15. Please provide detail of the instrument used (model, resolution, manufacturer, city) and the process of measurement.

Response: For experiment was used plot combine Wintersteiger Delta (Austria), working width – 2 m, manufacturer – Wintersteiger AG, Ried (Austria).

The measurements of plant residues length were made at random five different areas. One hundred straws were measured using precise measuring tape.

Comment: 16. L108: Provide variability of residue load (3700±???? kg ha-1) in the test plot.

Response: It was corrected. Variability of residue load was 3700±402 kg ha^-1. 

Comment: 17. L118: Please show the working depth in Fig. 1.

Response: Corrected. The working depth is shown in Fig. 1.

Comment: 18. L123–126: Please justify the treatment levels.

Response: Treatment levels were justified according the other's scientist recommendations [35,42,44] and according a fit strip width on maize, sugar beet, soy and other plants to grow in wide strips. Before experimental research were carried out theoretical research to find out dependence of strip width on row cleaners technological parameters [9].

Comment: 19. L114–18: Please also add a description of the prime mover (tractor?) used and how the speeds were controlled and measured.

Response: Description is added to subsection 2.2. Experimental settings.

Comment: 20. L123–126: Please add plot sizes used, statistical design followed and number of replications used.

Response: Research were performed in 50 m² sizes of plot with five replications. This is provided to subsection 2.2.

Comment: 21. L132–136: Procedure not clear. Please write the procedure clearly. Also, please add how the pre-test residue load was measured.

Response: Procedure is rewrite in manuscript.

Comment: 22. L 138: Please explain more clearly how distance of the removed plant residues was measured. A figure/drawing can be useful to clarify this.

Response: Drawing is provided in the subsection 2.2.

Comment: 23. L178: “plant residues increasing just slightly, on average approximately 3% ....” – please check it. Its more than 3% in Fig. 3a!

Response: We checked and 3% is correct: “According to the obtained empirical model data it was determined that increasing the driving speed from 1.3 to 3.1 m s^-1 at an interval of 0.3 m s^-1, when the slip angle is constant, resulted in part of the removed from the strip plant residues increasing just slightly, on average approximately 3%”. We provide values:

Comment: 24. Please add an observation/comment on how much residues were entangled in to the row cleaner. How did it change due to speed, rake angle, gap?

Response: In front row cleaner was small gap so plant residues did not entangle.

To prevent the plant residue from clogging up between the discs, the discs were shifted by a distance of 130 mm in relation to each other in the direction of driving. Driving speed, rake angle and gap had no influence to the plant residue entangle into the row cleaner.

Comment: 25. Please remove the values (turn off ‘add data labels’) in all the Charts (Fig. 3a–5).

Response: Values removed from the Charts.

Comment: 26. L179–182: Please explain the scientific reason(s) behind this. Please also explain the difference between the experimental and empirical values.

Response: It is added in manuscript: “According to experiments and the multiple regression model we can affirm that the driving speed does not affect the amount of removed plant residue, because by increasing driving speed the equal size soil surface area is affected.”

Difference between the experimental and empirical values on average was approximately 12%.

Comment: 27. L184–187: Please explain the scientific reason behind this. Please also explain the difference between the experimental and empirical values.

Response: Increased slip angle affected larger area the soil surface. Difference between the experimental and empirical values on average was approximately 12%.

Comment: 28. L204–214: Please explain the scientific reason behind this. Please also explain the difference between the experimental and empirical values.

Response: The increase of the driving speed increased inertia force and due this reason the distance of removed plant residues increased. Difference between the experimental and empirical values on average was approximately 10%.

Comment: 29. L231–232: Please clarify the sentence.

Response: The sentence was rewritten in manuscript.

Comment: 30. L233–235: Please explain the scientific reason behind this. Please also explain the difference between the experimental and empirical values.

Response: Difference between the experimental and empirical values on average was approximately 11%.

Author Response File: Author Response.doc

Round  2

Reviewer 2 Report

The paper is improving in clarity and content.

The new title is good. The change to use of slip angle is also good.

The definition of spacing between row cleaner discs is still not clear.  A top view is needed to be added to Figure 2 to show that both discs are given the same slip angle and how the disc clearance is measured.

I do not see any benefit of the multiple regression analysis to the papers outcome and it should be removed.

Figure 5 needs a better title for the y axis.  Is it “Removal of residue from strip (%)” ?  This need to be clearly defined. As [1 – (mass remaining/original mass)] x 100%.  It should be made clear that ideal is 100% removal.

Graphs would be clearer without the regression lines.

Be clear - was the plot length 50 m?

Be clear – was it a factorial experiment of 3 gaps x 3 slip angles x 4 speeds.  An analysis of variance would be a better statistical approach to show significance of factors.

Figure 4 Y axis title would be better as “Maximum residue movement from strip centre (mm)”.

The conclusions need to be strengthened and this can be done by adding a stronger hypothesis at the end of the introduction and then the conclusions address that.

Author Response

Dear Reviewer,

First of all we would like to thank for additional comments, detailed recommendations and contributions to improving the quality of this manuscript. All of the issues raised in the comments were corrected and are listed below. All revisions are highlighted in the text.

On behalf of all authors,

Dr. Kristina Lekavičienė

Vytautas Magnus University, Lithuania

Answers to comments:

Comment: The definition of spacing between row cleaner discs is still not clear.  A top view is needed to be added to Figure 2 to show that both discs are given the same slip angle and how the disc clearance is measured.

Response: In response to comments mentioned by reviewer, Figure 3 and description before Figure 3 was added for clear understanding the definition of spacing between row cleaner discs.

Comment: do not see any benefit of the multiple regression analysis to the papers outcome and it should be removed.

Response: Taking into account the suggestion of Reviewer we want clarify. Multiple regression analysis allows predicting how plant residues are removed changing the parameters in which have not been experimented. In addition, the aim of this work was to compare experimental results with analytical results.

Comment: Figure 5 needs a better title for the y axis.  Is it “Removal of residue from strip (%)” ?  This need to be clearly defined. As [1 – (mass remaining/original mass)] x 100%.  It should be made clear that ideal is 100% removal.

Graphs would be clearer without the regression lines.

Response: According to Reviewer comment, Figure title for the y axis was reformulated and clearly defined, that ideal is 100% removal of residue from strip.

Comment: Be clear - was the plot length 50 m?

Response: The plot length was 50 m.

Comment: Be clear – was it a factorial experiment of 3 gaps x 3 slip angles x 4 speeds.  An analysis of variance would be a better statistical approach to show significance of factors.

Response: Taking to suggestion, the differences among the treatments analysed were assessed by calculating the least significant difference (LSD) at 0.05 probability by using the Tukey HSD method. Graphs and subsection 2.5 were supplement.

Comment: Figure 4 Y axis title would be better as “Maximum residue movement from strip centre (mm)”.

Response: Title corrected as “Maximum residue movement from strip centre (mm)”.

Comment: The conclusions need to be strengthened and this can be done by adding a stronger hypothesis at the end of the introduction and then the conclusions address that.

Response: Taking into account the suggestion the conclusions was strengthened by adding a stronger hypothesis at the end of the introduction.

Author Response File: Author Response.doc