Scaling-Up Conservation Agriculture Production System with Drip Irrigation by Integrating MCE Technique and the APEX Model

Round 1

Reviewer 1 Report

This is a manuscript to estimate the potential of Ethiopia to produce irrigated agricultural crops under conditions of conservation agriculture.  The authors have collected input data from a variety of sources, transformed and weighted this information, and then used modeling to identify sites suitable for irrigation.  Although this is an interesting and potentially valuable approach, the manuscript has several shortcomings, some of which are serious.  The usage of English is such that I sometimes could not understand the text—especially as it relates to the modeling exercise and the validity of modeling assumptions that were made.  In addition, all of the maps were of substandard quality, and several are so blurry that I could not read or interpret them.  The arrangement of the manuscript also needs improvement.  I looked carefully at English usage in the Abstract and Introduction section and include comments indexed by line below.  There are many other errors in English usage in other sections.  These must be corrected, but I as reviewer did not attempt to do so.  Here are my comments, arranged by line:

16               The Conservation Agriculture Production System (CAPS) approach with….

21               Delete the word “Where” at the beginning of the sentence.

22               Properties, not property

25               Delete the word “that”

30               Make it “land is available to produce”

43/44         Make it “caused exploitation of the”

53/55         Start the sentence with the word “The,” replace semicolons with commas.

59               Make it “Another concern”

60               Here and throughout, do not place a comma after the name of a cited author.

61               Make it “under irrigation.”

62               Have been identified

63               Make it “to large-scale adaptation at the country level”

67               Make it “scale-up of CAPS”

69               Make it “using the multi”

70               Make it “integrating the MCI”

76               Delete the first sentence here and cite the Figure at the end of the second sentence.

79/80         I am not sure what is meant by high climate variability and why it is important.  Please elaborate.

90               I would make this “has been used”

106             Should be described by Mu and Pereyra-Rojas.  The equation is not in these two investigators.

115/128    Figure 2 should be placed after its first mention in the text, not after it.  I also recommend citing Table 1 early in this paragraph, so that the reader can easily see your data sources.  Where did you get your soil texture data, and how was this information combine with climate data to get 39 classes?  Additional information is also needed on the APEX model.  You hardly describe it and do not cite a publication for its creation.  I am concerned that the model was calibrated at only a “few sites” in Ethiopia.  These are not indicated, and no details of the calibration rationale or results are given here.  Can you provide a rationale for accepting this as adequate calibration for this study, which was “built on the same model?”  In short, the information presented in this paragraph is insufficient to validate your data sources and their use in the model.  These issues must be addressed.

131/154    The abbreviations used in the five equations should be defined as you introduce the individual equations and not collected up and presented at the very end of the paragraph.  Also, what is the relationship between CAPS and CA?  Can you provide a convincing rationale for creating Eq. 4, which applies to Ethiopia, based on the results in Reference 8, which seem to apply to all of sub-Saharan Africa?

156             What is the evidence that the model is well calibrated for Ethiopia?  I note that you state “well calibrated” again and again in the manuscript, but I did not find the rationale for this statement.  Please clarify.

157             I think you mean to estimate and not to limit.

160             I do not understand this sentence, especially “kilometer clear wells to wells distance.”

166             Make it discussion, not discussions

175/176    I do not understand the % units used for slope.  Normally, slope is measured in degrees from horizontal.  What does greater than 100% slope mean?

178/179    Did you reclassify, or did you just combine classes?

Fig. 3          The maps here are fuzzy, and the legends in the figure are nearly unreadable.  These maps should be high resolution.  In addition, units should be indicated for Fig. 3C and 3D, and see the comment above at 175/176 about slope %.  The written legend under the figure should also indicate data sources—especially which data are from published sources (identify them) and which are your own data.

183             This information belongs in the methods section, not in results.  And at line 217:  more information that belongs in methods.

222             Make it “found to be the second”

Fig. 4          Must be replaced with high resolution maps.  The legends (in the figure and below it) should also be made more clear.  Give the words for N1 and S4 and indicate what the percentages that correspond to the various shades of green actually mean.

Fig. 5          There is narrative about suitability classes at line 100 (and at line 233), but the distinctions between the various percentages are not adequately described, so that the reader can understand the significance of this figure.  Please make modifications, so that this is clear.

242             I am not sure that I see natural breaks in the data.  Please clarify.

243             See earlier comment about the 39 regions.  Also, no need to place parentheses around the number.

Fig. 6          Maps here must be at high resolution.  I think you can delete Fig. 6C and simply refer the reader to Fig. 6D for rainfall.  I also think that you should refer to Fig. 6B when describing the ground stations at line 116.  And please indicate in the legend the sources of data.

263             Here again, you are giving a method in the wrong section of the manuscript.

Table 3      I think you can place this in the text.  The numbers in the second column are in a reference, and so what you have is just four coefficients for four vegetables.

Fig. 7/8     I cannot read either of these figures and thus was unable to evaluate the narrative that refers to them.  The quality is very bad.

Table 4.    You need to define the abbreviation SNNP.  Also, you need to better define the meaning of the heading that begins “Potential of GW yield.”  I am guessing that you mean that (taking Addis Ababa as an example), groundwater is sufficient to irrigate 1,200 ha of garlic and 3,000 ha of onions, but no tomatoes or cabbage.  But this is not crystal clear.

357             There are no conclusions in the conclusions section, except for the last sentence, which contains information that was already given in the previous section.  Instead of conclusions, this section contains summary information.  The section should either be deleted or replaced with narrative conclusions.

Author Response

Thank you for your constructive comments on our manuscript.

Author Response File: Author Response.docx

Reviewer 2 Report

I appreciate the Editor to give me a chance to review an interesting and valuable paper. I found some merits in the both methodology and results. In my opinion, this paper has a good potential to be published in the journal. However, I have also some concerns on the different parts of the manuscript. If the author(s) address carefully to all of my comments, I’ll recommend publication of the manuscript in the journal:

·        The quality of the figures is low.

·        Add/Replace the name of the study area to the Keywords.

·        In the last paragraph of the Introduction, the authors should clearly mention the weakness point of former works (identification of the gaps) and describe the novelties of the current investigation to justify us the paper deserves to be published in this journal.

·        What are the main differences of crop yields over the irrigable lands between garlic, onion, tomato, and cabbage and why?

·        What is the difference between figures 7 and 8?

·        In Table 4, highlight values that are more important and discuss them for better understanding readers.

·        Focus on the advantages/disadvantages of the proposed model (APEX) with respect to the obtained results.

·        How can extend the results in other regions with similar/different climates?

Author Response

Thank you for your constructive comments on our manuscript.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Thank you for seriously considering all of my suggestions.  While the English usage is much better than in the original version, there are still some sections who English usage could be improved.  These are mostly in the sentences added in revision.  For example:

L257 The suitability ranges cover different...

L330 Productivity was found to be...

L437 Scheduling would be incorporated...

L438 By "can be produced in relatively higher areas" I think you mean that more hectares are suitable for garlic and onions than tomatoes.  The phrase "higher areas" implies that you mean higher elevation (I don't think this is intended)

L440 Remove "Comparison of" and start with Production...

It would be very good if someone with excellent English language skills could go over the manuscript one more time.

Author Response

Reviewer 2 Report

I appreciate the authors because of addressing the comments. The quality of the manuscript is better than the previous version. However, the introduction needs to be improved by adding some useful papers. I have added some:

APEX simulation of best irrigation and N management strategies for off-site N pollution control in three Mediterranean irrigated watersheds

Soybean crop-water production functions in a humid region across years and soils determined with APEX model

Water conservation in irrigation can increase water use

Author Response

Thank you for your comments.

In the revised manuscript, we include the suggested papers (3 papers) where they are related to and added 4 more papers which are relevant.