Impact of Integrating Annual and Perennial Legumes under Coffea arabica on Sloping Land

Round 1

Reviewer 1 Report

The manuscript is very well structured.

However, the methodological design must be questioned.

Below I send my observations regarding what I think of the experimental design adopted.

I also present a suggestion on how to analyze the obtained data, due to the theoretical and practical value of this manuscript, which I consider very important for the current context of sustainability of world agriculture.

Due to this methodological disagreement, I was forced to stop the analysis at this point of the manuscript, as the results, discussion, and conclusions sections may present changes, depending on the new analyzes proposed and to be carried out.

Other considerations are inserted in the text.

Below are my considerations:

According to the experimental design observed in the methodology, it was found that the experiment was carried out in 26 different locations, and each location cannot be considered a block.

In this case, the analysis to be performed would be a joint analysis of experiments.

For this, each site (farm) should be planned in a randomized block design with treatments and a minimum of 4 blocks to preserve experimental precision.

The experimental design should be: The 26 experiments (locations/farm) were carried out in a randomized block design with "X" replications in the experimental subplots in time, 4x4, with four treatments in the plots and four times (seasons) in the subplots.

Statistical analyzes should have been formulated as follows: Joint analyzes of experiments were carried out, with the averages between treatments compared by Tukey's test; the means of the 26 sites compared by the Scott-Knott test, and the regression models compared by the F test.

Thus, with all sites having the same experimental design, a joint analysis of experiments could be carried out.

With this, it would be possible to compare the 4 treatments at each evaluation time (4), and for the 26 locations using Tukey's test.

To compare the 4 sampling times, regression models should be tested.

As the basic hypotheses of experimentation were not verified, the solution would be to use the t-test with a comparison of the means, two-by-two. For each location, a two-by-two comparison of means could be performed, using the t-test of two independent samples for treatments for each parameter evaluated.

 

The regression models for each variable should be tested using the F test as a function of the 4 sampling times.

Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

The authors need to revise the manuscript mainly because the soil sampling method should be clearly stated.  You didn't mention how many samples you collected, and why you stick only at 0-15 cm depth. please justify it. There are many font sizes, capitalization, and language issues.  Your conclusion should be revised. 

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

This is a nice study overall, well designed and executed and with its results carefully and critically analysed. It also has clear applicability to the farmers with whom the researchers have worked. I have just a few comments on how it can be improved.

First, while the research as such is well situated in the literature, I would like to see a little more 'bigger-picture' context. On page 1 we are told that "Worldwide, coffee is a crucial commodity and C. arabica is the most valued". More could be said here to underline the importance of the research: what is the volume/value of C. arabica traded globally per annum, for example, and why is it so valued? (Not all readers will necessarily know that it is used for the higher quality/value coffees enjoyed by very many drinkers both at home and served in major chains.) The sentence that follows talks about its importance specifically to Uganda but more recent (than 2013/2015) data could be included here, and a $ value put on the country's coffee exports for the most recent year available.

Second, the prose needs some attention: at various points in the text it is somewhat awkward and (less often) lacks clarity. For example, the opening sentence says that "high-altitude sloping land is predominantly utilized by smallholder farmers to produce Coffea arabica"; but what is really meant is  actually slightly different i.e. "smallholder farmers producing Coffea arabica predominantly use high-altitude sloping land for this purpose". Similarly, "production of C. arabica in Uganda has been restricted to high altitude sloping areas due to the required high input labor needs [I do not follow this line of argument - ?] and due to the lower incidence of leaf rust (Hemileia vastatrix) and of antestia [this does not need to be italicised as it is not the name of the genus] bugs at such altitudes". On page 2, we are told that "M. pruriens reduces soil erosion on land slopes of 15-25% ... and is among the best possible cover legumes for integration into coffee fields due to their fast establishment", but "their" is ambiguous here: I think it refers to M. pruriens, in which case this should read "its", not "their". The last sentence of section 4.1 on page 12, meanwhile - "To sustainably optimize above-ground biomass under C. arabica on sloping land, a combination of the annual M. pruriens with the perennial M. dura should be implemented" - is effectively repeated in the Conclusion (where it belongs) and can be removed here. And on page 13, the statement "This further collaborates findings ..." should read "This further corroborates findings ...". Please note that these are only a few exemplars and the whole text would benefit from careful reading to clear up such issues, please.

Third, the units used feel a little cumbersome at times. I am one of those who feels that "Mg/ha" is a faintly ridiculous unit as it really means mt/ha (metric tonnes per hectare). And do we really need altitude to be expressed as 'm.a.s.l.' rather than just as 'm', which would be understood in context; for example "... varying altitudes (1200-1650 m)" on page 3 would be clear enough. Figure 2 (page 4) does not show "Average monthly rainfall (mm) ..." since it presents data for two years separately; it simply shows "Monthly rainfall (mm) ...". Again, these are just exemplars and a full check for other such issues is needed.

Fourth, the presentation of tabulated data needs tidying up, please; at present the different fonts and font sizes used are visually off-putting.

Finally, the reference list needs attention in terms of standardisation/correction in the presentation of the entries given.

I hope that these comments are useful to the authors and look forward to seeing the article published in due course.

Author Response

please see attached file

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

I suggested a few modifications in the text where I inserted my considerations. 

Pay attention to scientific names where italic letters must be used. 

Insert in the footnotes of the tables the name of the tests used.

I suggest that the citations of tables and figures won´t be used in the discussion section. Use it only in the results section (but it is a single recommendation).

The first paragraph of the conclusion section must be suppressed because it is not part of the conclusion.

Congratulations!

Comments for author File: Comments.pdf

Author Response

Dear Reviewer,

Thanks for the comments that have guided us to greatly improve our manuscript. Please see the attachment for the point-by-point response to the comments.

Author Response File: Author Response.pdf