Intensification of Pearl Millet Production in Niger through Mechanized Sowing and Weeding, Seed Priming, Seed Treatment, and Microdosing
Round 1
Reviewer 1 Report
Review of ‘Agronomy’ manuscript by Nourou et al. “Intensification of pearl millet production in Niger through mechanized sowing and weeding, seed priming, seed treatment and microdosing.”
This manuscript compares the performance of a package of improved practices with farmers’ practice using minimal levels of inputs. Data were collected at three sites in two years and the authors conclude that the improved practices resulted in a large (55%) increase in grain yield and reductions in labour usage. This is impressive although the net benefits to farmers who might adopt the improved package were not calculated or discussed (see later).
The current manuscript is not yet suitable for publication in an international journal and needs attention paid to a number of issues:
The Tables use a comma instead of a decimal point. A decimal point is generally used in English-speaking journals and, in any case, the authors have used a point throughout the text.
The Materials and Methods is not detailed enough. Need to provide more detail on how crops were managed. For instance, did the control treatment have any fertiliser added? What is the equivalent per hectare of 0.3g/hill (there is no mention of how many plants per hill – and its variation- resulted from the treatments, unusual in work involved a planter).
The tool used for mechanical weeding is not described at all.
The experimental design needs to be explicitly stated so that the subsequent statistical analysis and presentation of data can be better understood and interpreted. Were there really 18 replicates per treatment (L82)? If so, why so many? Were the same treatments applied to the same plots in both years? This is important as it speaks to follow-on effects.
Why were no costs assigned to these packages? It would be relatively simple (and extremely informative) to do an elementary benefit: cost analysis.
There were no significant differences between sites or years in any of the Tables except Table 6 (and the data in T6 is of little importance and could be easily presented in the body of the text). If that was the case (and it’s difficult to be sure because the reader is unsure of the experimental design used) then all the current Tables could be condensed into one Table, or possibly two, that reports overall treatment effects together with appropriate estimates of variability, e.g. SEs, SEMs or confidence limits.
While the data show pretty conclusively that the improved package outperformed farmers’ practice, the yield advantages were a consequence of increased levels of inputs, including fertiliser versus no fertiliser. Effectiveness of a technology is no guarantee of attractiveness to farmers and the authors need to address this issue (see previous comment on B: C analysis).
In addition, the Discussion should include a wider consideration of the pros and cons of mechanisation. For instance, the capital costs of the planter and weeder and the fact that they are used for a relatively limited time during the year, particularly in rainfed situations where only one crop per year is possible (as here) and the time available for hiring or collaborative use is limited. There may also be problems associated with damage of softened, swollen primed seed in mechanical planters – not apparent in this study, it seems, although data on seeding rates and final densities are missing. In a similar vein, the formulation and consistency of fertiliser granules moving through mechanical planters when mixed with seed as here may also be a problem.
There are some grammatical errors and misspellings that could be eliminated during the next iteration by using the checking facilities in word processing software.
Author Response
Comments and Suggestions for Authors
Review of ‘Agronomy’ manuscript by Nourou et al. “Intensification of pearl millet production in Niger through mechanized sowing and weeding, seed priming, seed treatment and microdosing.”
This manuscript compares the performance of a package of improved practices with farmers’ practice using minimal levels of inputs. Data were collected at three sites in two years and the authors conclude that the improved practices resulted in a large (55%) increase in grain yield and reductions in labour usage. This is impressive although the net benefits to farmers who might adopt the improved package were not calculated or discussed (see later).
The current manuscript is not yet suitable for publication in an international journal and needs attention paid to a number of issues:
The Tables use a comma instead of a decimal point. A decimal point is generally used in English-speaking journals and, in any case, the authors have used a point throughout the text.
Comment: This is corrected.
The Materials and Methods is not detailed enough. Need to provide more detail on how crops were managed. For instance, did the control treatment have any fertiliser added?
Comment: No fertilizer was added to the control. A better description about how the crops were managed is inserted. Lines 88-93, line 101.
What is the equivalent per hectare of 0.3g/hill (there is no mention of how many plants per hill – and its variation- resulted from the treatments, unusual in work involved a planter).
Comment: 0.3 g NPK hill-1 corresponds to 3 kg ha-1 when crops are sown at a density of 10 000 hills ha-1. Line 103.
The tool used for mechanical weeding is not described at all.
Comments: This is now better described in the manuscript. The tines were mounted to the planter and the planter/multicultivator is then for weeding between rows. Handweeding is in addition undertaken within the rows. Lines 121-123.
The experimental design needs to be explicitly stated so that the subsequent statistical analysis and presentation of data can be better understood and interpreted. Were there really 18 replicates per treatment (L82)? If so, why so many? Were the same treatments applied to the same plots in both years? This is important as it speaks to follow-on effects.
Comment: Each site had 36 elementary plots and since there was only 2 treatments there was 18 replications per site. The high number of replications was used in order to be sure that reliable results could be obtained. This was the first time to test the planter and the precision in delivery of seeds and fertilizer was not known at the beginning of the test. This turned out to not be a problem. The cost of having many replications were low for this experiment, therefore we could afford to use many replications. Permanent plots were used for the two years. See lines 96-98
Why were no costs assigned to these packages? It would be relatively simple (and extremely informative) to do an elementary benefit: cost analysis.
Comment: A table the full economic analysis is now inserted. The results of the economic analysis is presented in the result chapter and discussed in the discussion chapter. Lines 146-154, 258-266, 336-355.
There were no significant differences between sites or years in any of the Tables except Table 6 (and the data in T6 is of little importance and could be easily presented in the body of the text). If that was the case (and it’s difficult to be sure because the reader is unsure of the experimental design used) then all the current Tables could be condensed into one Table, or possibly two, that reports overall treatment effects together with appropriate estimates of variability, e.g. SEs, SEMs or confidence limits.
Comment: The table 7 and 8 are merged into one.
While the data show pretty conclusively that the improvewwd package outperformed farmers’ practice, the yield advantages were a consequence of increased levels of inputs, including fertiliser versus no fertiliser. Effectiveness of a technology is no guarantee of attractiveness to farmers and the authors need to address this issue (see previous comment on B: C analysis).
Comment: The economic analysis shows that the improved package is economically very attractive for the farmers. Lines 258-266, 334-355.
In addition, the Discussion should include a wider consideration of the pros and cons of mechanisation. For instance, the capital costs of the planter and weeder and the fact that they are used for a relatively limited time during the year, particularly in rainfed situations where only one crop per year is possible (as here) and the time available for hiring or collaborative use is limited. There may also be problems associated with damage of softened, swollen primed seed in mechanical planters – not apparent in this study, it seems, although data on seeding rates and final densities are missing.
Comments: Seed priming did negatively effect delivery of seeds by the planter. The reason why not such problem occurred was that the seed were surface dried for one hour prior to sowing to reduce the stickiness of the seeds. Seed priming for 8 hours in water did not result in of the swollowing of the seeds. Lines 357-361.
In a similar vein, the formulation and consistency of fertiliser granules moving through mechanical planters when mixed with seed as here may also be a problem.
Comments: This is issue is addressed in lines 357-361.
There are some grammatical errors and misspellings that could be eliminated during the next iteration by using the checking facilities in word processing software.
Comment: The discussion is extended to include discussion on profitability and technical problems related to the use of the planter.
Submission Date
16 March 2020
Date of this review
26 Mar 2020 18:23:58
Author Response File: 
Author Response.docx
Reviewer 2 Report
High quality and novel research. A very important information for semi-arid sub Saharan Africa especially for more than 300million people who use pearl millet as their staple food. A very strong introduction, well packed and nice to read with less flaws in grammar. However, the manuscript requires improvements especially on the method, results and discussions. Incomplete results presentations and weak discussions is of major concern for the manuscript to catch the attention of wider scientific community. Below are my specific comments:
In Abstract, L20 reads 71,1%, instead of period there is a comma, and this applies to the entire manuscript, and all the tables. Please correct accordingly.
I have seen NPK 15-15-15 ha-1, it would be better to define this explicitly.
L66-70, the treatments are unclear, it would be much better to strictly provide specific objectives here and define the treatment much wider in the method section.
L94 , The field were..., (consider re-writing it more clearly)
L106, state whether it was sun dried or oven dried (explain)
Section 2.1 - Provide a map that describe the location of the site
Section: 2.3 - I suggest you Provide the layout drawing of the experiment, then the text would be easily understood by readers
L124 - I suggest you define clearly the term Labour use or I recommend you adopt and stick to the term "time" as clearly presented in L136 and paragraph L143-146.
Section 3.2
I advice that L150-154 would make sense if the days are not writen with decimals. Sensors were not used to monitor the emergence, therefore it makes sense to report the days without decimals,
Similarly, L162-164, Average weed density would make more sense if rounded as normally there is no half weed or else
L169 , the first word should be "Mechanized..?"
Section 3.3 both text and table have only reported one treatment, there lack of comparison, what were the results for manual treatment?
Section 3.5, also consider rounding the number
L251-257, Is there a way effects of priming could explicitly be explained? As you cited, it looks to have huge influence on the results in terms of yield for previous research. I wonder if the whole package is not influenced by it
L276-278 I recommend to re-write, for now it reads as wish lists. Unless investigated and supported by results, it can not be presented that way.This also applies to L280-291
Author Response
Comments and Suggestions for Authors
High quality and novel research. A very important information for semi-arid sub Saharan Africa especially for more than 300million people who use pearl millet as their staple food. A very strong introduction, well packed and nice to read with less flaws in grammar. However, the manuscript requires improvements especially on the method, results and discussions. Incomplete results presentations and weak discussions is of major concern for the manuscript to catch the attention of wider scientific community.
Comments: The chapters materials and methods, results, discussion and conclusion have been strengthened.
Below are my specific comments:
In Abstract, L20 reads 71,1%, instead of period there is a comma, and this applies to the entire manuscript, and all the tables. Please correct accordingly.
Comment: The commas are replaced by a period.
I have seen NPK 15-15-15 ha-1, it would be better to define this explicitly.
Comment: 0.3 g NPK hill-1 is equivalent to 3 kg NPK ha-1 when using 10 000 hill ha-1. Line 103.
L66-70, the treatments are unclear, it would be much better to strictly provide specific objectives here and define the treatment much wider in the method section.
Comment: Presentation of the treatments is shortened in the introduction. A more detailed description of the treatments is given in the material and methods chapter. Lines 68-73, 88-104,
L94 , The field were..., (consider re-writing it more clearly)
Comment:New sentence inserted. The fields were prior to sowing ploughed and leveled in order to facilitate planting. Line 115.
L106, state whether it was sun dried or oven dried (explain)
Comment: The seed and stover were sundried before weighing. Line 130
Section 2.1 - Provide a map that describe the location of the site
Comment: A map is inserted with locations of the sites. Line 82.
Section: 2.3 - I suggest you Provide the layout drawing of the experiment, then the text would be easily understood by readers
Comment: A figure showing the layout of experiment is inserted. Line 108.
L124 - I suggest you define clearly the term Labour use or I recommend you adopt and stick to the term "time" as clearly presented in L136 and paragraph L143-146.
Comment: We add (days ha-1) to avoid any misinterpretation. Line 161.
Section 3.2
I advice that L150-154 would make sense if the days are not writen with decimals.
Comment: Days are now written without decimals
Sensors were not used to monitor the emergence, therefore it makes sense to report the days without decimals,
Comment: Emergence is not measured in days, but in percent germination.
Similarly, L162-164, Average weed density would make more sense if rounded as normally there is no half weed or else
Comment: Number of weeds given without decimal in tables
L169 , the first word should be "Mechanized..?"
Comment: The word changed from “mechanical” to “mechanized” as suggested. Line 206.
Section 3.3 both text and table have only reported one treatment, there lack of comparison, what were the results for manual treatment?
Comment; The data for the manual the weeding treatment (T0) is not reported as there was no such destruction of plants in this treatment. This is now explained in the text. Line 208.
Section 3.5, also consider rounding the number
Comment. Numbers given without decimals.
L251-257, Is there a way effects of priming could explicitly be explained? As you cited, it looks to have huge influence on the results in terms of yield for previous research. I wonder if the whole package is not influenced by it
Comment: The seed priming effect is now better explained in the text. Seed priming has also previously been shown to speed the develop of the plants. Lines 321-324.
L276-278 I recommend to re-write, for now it reads as wish lists. Unless investigated and supported by results, it can not be presented that way.This also applies to L280-291
Comment: The final part of the discussion and the conclusion has been extended to also include the result from the economic analysis. The economic assessment makes it possible to give a stronger recommendation of the improved package. We think the claims now made about the improved package are well documented by the results (tables) and is not a “wish list”. Lines 336-355.
Round 2
Reviewer 1 Report
Review of REVISED ‘Agronomy’ manuscript by Nourou et al. “Intensification of pearl millet production in Niger through mechanized sowing and weeding, seed priming, seed treatment and microdosing.”
The authors have addressed most of the issues I raised regarding the original version of the manuscript. In particular, the new consideration of costs and benefits adds a great deal to the work. There remain a few points to consider. For instance, the M and M section still lacks some pertinent details, such as the dosage of the seed dressing, a consideration of how many plants per hill there were in the two treatments, and how the materials in the field were dried (to constant weight?). There is some repetition (L118-119 with L103-104, for instance) and the whole manuscript needs to be checked for spelling AND grammar (e.g. L115 ‘ploughed’ should be ‘plough’). Figure 2 is not necessary and should be omitted.
The main remaining issue to be addressed is the lack of a clearly defined statistical model. That has resulted in confusion about how the data have been analysed and consequently how the results have been interpreted and presented. As Tables 1 to 5 stand now, it appears that there are no statistically significant differences due to either site or year. Table 6 indicates that there were significant differences due to site and year and so that Table layout is justified. If there really were no site or year effects then there is no reason to present results for site or year separately – if you have tested for main effects and interactions and found that there weren’t any, then data should be pooled and results presented only for treatment effects as you have done in new Table 7. The same applies to your new Tables 8 and 9. That would allow smaller, clearer Tables or fewer Tables with more variables as I suggested in my earlier review. The result would be a much more concise paper and the data would support even more strongly the superiority of the improved package across sites and years. If there WERE significant differences due to site or year or interactions, then the comparisons shown in the current Tables are inaccurate.
A second minor point that would improve the paper would be for you to discuss the possibility that there could have been residual effects in the second year because fertilizer was applied to the same plots two years running.
Author Response
Comment to reveiwer 1.
- Dosage of seed dressing.
Comment: Dosage give line 111.
- How many plants per hill.
Comment: There are 2-3 plants per hill. Line 91.
- Was the material dried to constants weight?
Comment: The material was sundried for 2 to 3 weeks before weighing. Line 126.
- Avoid repetition concerning the lines 103-104 and lines 118-119.
Comment: The text has been amended to address this issue.
- New tables have been developed which give a better overview of the significant the main effects and the interactions. We present the results for all the sites as in some cases the interactions between the main effects were significant. We have reduced number of tables to 4 as compared to 10 in the previous version of the paper.
- Residual effect of fertilizer:
Comment: We do think that there is any residual effect of the fertilizer because the application rate was very low.
Reviewer 2 Report
General comment: The manuscript is improved
Specific comments
- Indicate the years that experiments took place and the seasons. Can be added at the objectives as well as in the abstract
- Study site description (L76-79) you can also add average weather information for the study sites and probably the soil types
- Look for more citation that compare or contrast or support your results during discussion (L 336-373)
- Check for grammatical errors throughout
Author Response
Comment reviewer 2.
- Indicate the years that experiments took place and the seasons. Can be added at the objectives as well as in the abstract
Comments: The years have been indicated in the abstract and in the Materials and Methods. Line 17 and line 78.
- Study site description (L76-79) you can also add average weather information for the study sites and probably the soil types.
Comment :The isohytes are given for the locations. Line 77-78. The experiment was conducted on adid sandy soils (arenosols). Lines 76-77.
- Check for grammatical errors throughout
Comment: The manuscript has been checked for grammatical errors and many mistakes have been corrected.
