Determination of Crop Coefficients and Evapotranspiration of Potato in a Semi-Arid Climate Using Canopy State Variables and Satellite-Based NDVI
Round 1
Reviewer 1 Report
Thanks for a sound and very professionally presented paper. My comments refer to the listed lines below.
132, 135, 136, 380 , 420, 434 and many others: most of the instances of the use of “parameters” is incorrect. For instance, on L 132 LAI is a “parameter” but on L 206 it is a - correctly – a “variable”. Rainfall and other metrics that you observe are not environmental “parameters”: they are variables. A metric that you can adjust, e.g. the “nitrogen uptake adjustment factor” in WOFOST or POTSIMUL (I have just made that up!) is a parameter. There are some cases where it is not so easy to tell the difference between a variable and parameter, but they are rare!
146: vine kill-off
Comment: please explain if vines are killed mechanically, chemically...?
187-189: based on the assumption that the shallow root system of the potato crop is unable to access soil water beyond a soil depth of 1 m
Comment: can you provide some reference to support the assumption?
231-232: -In(1-FIPAR)
Comment: change capital i in "-In..." to small L
243: classification
Comment: I am not sure this is the correct term. You wouldn’t lose much if you said “Canopeo® green canopy cover estimation as percentages.”
351, 352:
I fail to understand the meaning of °Cd
410, 412: Fields 2 and 3 received 76 and 49 mm more actual irrigation than the simulated irrigation requirement. This suggests that Fields 2 and 3 received more irrigation water than what was required
Comment: and the other way round, of course?
427, 440: ±3.8 m2 m-2
Comment: since there is no negative LAI, I assume this means “about” or “approximately”
431, 576
Comment: same as above
443: 0.61 (0.6/0.99)
Comment: 0.61 (0.60/0.99), I assume?
453, Figure 4a
Comment: the equation for Fitted NDVI as written does not correspond to the curve
478: all fields were grown for seed
Comment: please mention this earlier, in section 2 (Materials and methods)
559-560: The close similarity in the temporal trends observed for NDVI, GCC, FIPAR, and LAI suggests that potato phenology can be remotely monitored using NDVI.
Comment: indeed. A quote or two from the literature would nevertheless be welcome
Author Response
see the attachment
Author Response File: 
Author Response.docx
Reviewer 2 Report
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Title |
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It describes correctly the article. |
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Abstract |
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The abstract is a concise and complete synthesis of the work. |
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Keywords: |
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They are all appropriate |
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1. Introduction |
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In a region of southern Africa where water is a scarce resource, methodologies are proposed and compared to improve the irrigation scheduling and, in particular, water use efficiency of potato crops. |
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This is confusing. It should establish well the differences between the concepts of real evapotranspiration (ET) and maximum evapotranspiration (ETmax=ETo*Kc). |
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The objectives are well established. |
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2. Material and Methods |
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Study area and all procedures are well documented |
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All calculation procedures are presented in detail and thoroughly explained |
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Crop ET was calculated as the product of Kc and ETo (Equation 17) [9]. ET = Kc * ETo It is ET or ETmax? |
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3. Results |
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All results are presented in an orderly manner and they are analyzed in depth. |
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Figures are all necessary and facilitate the interpretation of the article. |
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ET estimated by the LINTUL-Potato model were accurate? This model was calibrated previously in each field? |
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4. Discussion |
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I believe that the specifications incorporated are appropriate |
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No consideration is incorporated into the discussion about the provenance of the ET estimates from the LINTUL-potato model. Was the model properly calibrated according to the test conditions? |
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5. Conclusions |
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The conclusions are fully consistent with the results obtained |
Author Response
see the attachment
Author Response File: Author Response.docx
