Evaluating Irrigation and Farming Systems with Solar MajiPump in Ethiopia

Round 1

Reviewer 1 Report

• L28-31: Compared to farmer's practice, water productivity was significantly improved under 28the CA farming and the drip irrigation systems for both irrigated vegetables(garlic, onion, cabbage, 29potato)and rainfed maize production.The water productivity of garlic, cabbage, potato, and maize 30was increased by 256%, 41%, 71%, and 9%, respectively, under CA as compared to conventional 31tillage (CT) even under overhead irrigation.

How CA and drip irrigation effects were separated?

• Line 79-82: The MajiPumpis a solar-powered water-lifting technology that was introduced in Ethiopia in 792017 by the Appropriate Scale Mechanization Consortium of the Feed the Future Sustainable 80Intensification Innovation Lab (SIIL)funded by USAID (United States Agency for International 81Development).  

“funded by USAID (United States Agency for International 81Development)”.   Should go to Acknowledgement part

• L 91-92 Smallholder  vegetable  production  is 91considered as a strategic approach to minimize children’s death and stunting caused by malnutrition, 92which  is  a  serious  challenge  in  Ethiopia[40]...L 96- 98: CA with farmer’s conventional tillage (CT) practice;in terms of water productivity and yields of key crops[garlic(Allium sativium97L.), onion (Allium cepaL.), cabbage(Brassica oleraceaL. var. captata), potato(Solanum tuberosumL.), and maize].

How these two arguments come together?

• Experiment 1: CA vs CT under overhead irrigation conditions,Experiment 2: Drip vs overhead irrigation under CA,Experiment 3: intercropping 250 m2 with CA andanother250 m2 with CT practice

Three are separate experiments were compared at two different sites, I wonder how site effect was taken into consideration? discussion is quite easy to follow in subheading but M&M and results are difficult to follow.

• Figure 3: Would be nice to see cropping season in this figure, I also wonder why one needs irrigation when distribution of rainfall is not so bad, so including crop growing seasoning figure may justified the need to those how are not much familiar with the experimental areas. It get bit clear, if one closely look at Figure 3 and Table 1. So I highly recommend to bring this information together. Also mention when irrigation was performed.
• Line 263: Farmers could decide the irrigation interval and amount based on their field observation on soil moisture.

As you are working with applied N and water can co-limit the response of N. I would recommend to have look on recent advance on N-water co-limitations

 See Effect of post-sowing nitrogen management on co-limitation of nitrogen and water in canola and mustard, A Riar, G Gill, G McDonald, Field Crops Research 198, 23-31

So discuss your results in the light of this aspects

 

Table 2: it is hard to see how C.V was calculated, from whole date set or from individual data sets.  

 

• Line 281-283: Based on CV analysis, the variability of soil properties was low across experimental plots at both sites (i.e. Alefa and Affesa)283satisfying precondition for paired management comparisons.

I do not agree with this interpretation, soil are quite variable for some measurements. Please explain, I think this can be solved by using a different statistical analysis approach and considering sites as fixed factor or at least random factor. But for sure no on pooling bases.

The statistical model used to analysis three experiments are not appropriate and variation of sitexirrigationXCA/CT are not fully considered and evaluated separately so i recommend to reanalysis the data considering the interactions of these factors

Author Response

Thank you very much for your constructive and useful comments. In the revised manuscript, we tried to address all comments for the improvement of the manuscript. 

Author Response File: Author Response.docx

Reviewer 2 Report

Line 176. Why the soil layer was taken as 0-30sm, 30-60sm, and 60-90sm?

Line 177. Have you conducted analyses of the soil salinity? Explain please you meaning at "The soil samples were analyzed...physio-chemical properties (field capacity, permanent wilting point, soil texture, available organic matter, pH, total N, available P, and available K)". 

Author Response

Thank you very much for the constructive and useful comments. In the revised manuscript, we tried to address all the comments for the improvement of the manuscript. 

Author Response File: Author Response.docx

Reviewer 3 Report

The paper promises to deal with an interesting topic but the content deviates from this promise. The link between the pumps and the irrigation/land management practices is weak or forced and this needs to be strengthened and focused. The study design requires rewriting to focus and detail the experiment. Some specific details below:

A bit of review of small-scale irrigation practices in the introduction to focus the problem of interest.

 

Method

Line 110: what is meant by ‘dominant soil texture’? Is this based on soil samples or whole-site soil map/analysis? The soil information seems coarse. Site-specific soil analysis information would be useful.

Line 114-115: are these irrigated at both sites? Two different sites are being used so using ‘…in the study area’… is confusing and/or seeks to mask some lack of information.

Figure 1: the map is confusing… reducing the panels to Ethiopia, the district and indicate the towns or sites.

What is this CA? What type/component?

The experimental description requires some clarity and a bit more detail. The dimensions in the description do not match those in the figure. Again, from the figure, is it the entire length that is 10 m? how many replicates? And is t-test design appropriate (seeing that there are multiple factors with different levels, wouldn’t an ANOVA-based or factorial design have been better)? It’s important to carefully describe the layout/design in details as even the distance between subplots and plots can have advective effects and these should be accounted for.

The introduction of the maize-forage vetch is surprising, disruptive and seems contingent or pointless. What’s the point of all these combinations or isolated experiments?

Ok, I now see some further information. Yet, the study needs a proper, clear description of the design/approach so that we clearly know the treated and untreated components. e.g. of the 10 farmers, how many used their fields for what? Only one type of solar pump was used? If not, how were the different types factored in the design/approach?

So, is this study about the pumps or about water productivity? The only test for the pumps seems to be lifting water and so parameters specific to this could have been the focus of the study. This seems to have no effect or relationship whatsoever with the pump (except just making the water available).

 

Results

Still not sure if the t-test is rightly used. Is this really a paired t-test or independent samples t-test? Does the improvement in plant height imply difference over time, or between the different factors? It is also not clear the plants were sampled from the plots/subplots for monitoring of the growth/yield parameters.  Same comments for the subsequent similar results.

Line 364: how do you disentangle the effect of land management from that of irrigation type? This is why t-test is not appropriate.

Author Response

Thank you very much for the constructive and useful comments. In the revised manuscript, we tried to address all comments for the improvement of the manuscript. 

Author Response File: Author Response.docx

Round 2

Reviewer 3 Report

Some clarifications have been provided in the responses but mostly not in the paper itself. As it stands, the paper looks like a development-oriented project rather than a hypothesis-driven study. This however can be improved. Suggestions:

i) Methods: separate the description of the experimental design for the two respective sites (Alefa and Affesa). This will clarify lots of the confusion including the use of t-test. The result should be reported accordingly.

ii) Results: soil properties (since plots are not homogenous or very close, it's important to report the minimum and maximum values as well). Same for the other similar results that follow (e.g. crop growth data).

Author Response

Thank you for your constructive and useful comments. 

Author Response File: Author Response.docx