Evaluating the Yields of the Rainfed Potato Crop under Climate Change Scenarios Using the AquaCrop Model in the Peruvian Altiplano

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

I finished the review of the paper “Assessing the Impact of Climate Change on Potato Crop Yields – A Case Study for Peruvian Altiplano”. From my review, I can see the paper has serious deficiencies which are listed below:

Title. Authors should add some words to express the work is related to AquaCrop model, irrigation and climate change scenarios.

Header of article. It will be necessary to add key words.

Introduction. Lines 27-33. Here, authors set up the general importance of climate change. Please, add some specific numbers related to climate change as the global average of temperature warm and the global percentage of precipitation change. These numbers are easily available on IPCC reports and other authors papers. If you can, add something related to surface runoff changes, it would be nicer. Consider removing the reference in line 27, since in general first sentence is for locate the reader in the context of the manuscript and catching the attention. Also, you start talking about global warming, but a definition of this is required.

Introduction. Lines 34-41. Authors continue talking about the climate change importance. In these lines, they already mention agriculture; however, these sentences are pretty general. Consider adding information about how the increase of a specific temperature threshold affects physiology of crops. Also, you could strength the paragraph saying that the water shortages reduce potential yield, be specific mentioning the effect of water shortage on crop production. How about the effects of frosts on crops? There are a lot of papers that talk about the effect of temperature and different levels of water supply on crop yields.

Introduction. Lines 42-52. Authors talk about climate change again, but paying attention, I see that so far, they have not provided with a definition of climate change. In lines 47-50, authors suggest some adaptation strategies, but specifically in this paragraph context, that is not required, I would keep that information for results and discussion section where practical recommendations will be needed. In line 48, the first letter of word “Adopting” not must be in capital. Also, I see this paragraph is very related to paragraph in lines 34-41; take care of this given that reader can be confused; for this I recommend to join both paragraphs and merging both ideas. When the reader is sent to one context, and then he goes back to another showed in previous paragraphs is when the confusion take place.

Introduction section. Lines 53-56. The ideas showed here are very similar to the ones explained in another paragraphs.

Introduction. At the end of this section objectives of research are not provided.

Synthesis of the introduction review. All the ideas presented here are very general. Nothing is commented about the situation of climate change in the world, for example, the extent of warming or precipitation change in the past century. No definitions of climate change or global warming are provided. Paragraphs 2 and 3 are ambiguous given that both talk some about the same topic. I recommend to set the research up adequately, in the first paragraph provide general ideas about global climate change. Another paragraph should content information about the effect of climate change in crops, strengthening this with references. Also, in some paragraph to talk about the importance of potato production in Peru and specifically in the local context. In somewhere to add information about the vulnerability of potato to climate change. Also, talk about why this region is important to be evaluated with the climate change approach in general and in the context of potato specifically, of course, for this also using references. At the end of introduction, the objectives of the research must be clearly presented. Pay attention that all the introduction must be prepared from the general to the specific ideas, where the specific ideas must be evaluation of climate change impact in potato in Peru as indicated in the title.

Materials and methods section. Study area subsection. Lines 66-75. Perhaps, here would be very illustrative to use graphs when describing climate variables, I mean provide with graphs for the variability in through the months of the year.

Materials and methods section. Experimental details subsection. You mention two irrigation regimes: Optimized irrigation rate and reduced irrigation rate. Please explain each regime characteristics. How did you manage the water, did you use crop evapotranspiration, water balance, Kc, concepts? Explain at detail the frequency of irrigation and what was the criteria for defining it (how about soil moisture?). According to the most articles about this topic (calibration of growth models and water use), just two treatments is not enough for a study like this, in my opinion this is the main weaknesses of the paper.

Materials and methods sectio. Authors do not say where did they take data soil information.

Materials and methods section. Climate data subsection. Line 97. You say “…adjusting the Hargreaves coefficients for local conditions…”, could you be more specific about what coefficients?

Materials and methods section. Climate data subsection. In this section you say that given the limitations on climate variables availability you used the Hargreaves approach. However, in Figure 3, in the climate box you show a bunch of variables such as: precipitation, temperature (maximum and minimum), wind speed, sunshine hours, solar radiation and relative humidity; this is some confused.

Materials and methods section. AquaCrop Model Calibration and Validation subsection. It is required a wider description of the AquaCrop Model and also how this model was fed with crop, climate, soil and irrigation information.

Materials and methods section. AquaCrop Model Calibration and Validation subsection. Lines 114. Please use the best english concept for “reduced irrigation lamina”, I think the last word is in spanish.

Materials and methods section. 2.5. Development of climate change scenarios subsection. It will be fine to add a summary of the description of rcp4.5 and rcp8.5 scenarios. Not all readers are familiarized with this.

Results section. 3.1 subsection. Why this title subsection was written in Spanish?

Results section. 3.1 subsection. Lines 141-143. You already mentioned this in lines 110-112.

Results section. 3.1 subsection. Lines 151-153. Part A of Figure 4, it is not a calibration step at all, rather it is a comparison of the simulated vs observed canopy cover. Part B of Figure 4, authors say it is the correlation output, but the Pearson Correlation Coefficient is not seen, rather it looks like a simple regression analysis given that equation and Determination Coefficient are provided; rho is shown in Table 2.

Results section. 3.1 subsection. Lines 147-148. You say “Table 2 shows the performance statistics of the AquaCrop model for the calibration phase”; this table also shows statistics for the validation phase, perhaps you may want modify your sentence.

Results section. 3.1 subsection. Lines 159-160. Statistics you show here were obtained during the calibration, but in line 157, you say validation phase. Please, check.

Results section. 3.1 subsection. Figure 5. The same comment than for Figure 4.

Results section. 3.1 subsection. Lines 141-188. I think, here, authors are not gaining the most benefit of the results. You could add information, for example, explain the reason for which obtaining these results; and strength it with various references. Also, you need to take into account all the agronomic meaning of the information you have presented here.

Results section. 3.4. Crop yields under climate change scenarios subsection. Line 261. Table 7 is not mentioned in any paragraph.

Synthesis of results section.

No references are used. Authors do not provide any explanations about the results causes, neither comparison with another researchers results. Did anybody get similar behavior results? Were these similar/different with respect the ones you got? It is important to give the practical meaning of statistics you are using to measure the goodness of the model in calibration and validation; I mean, what does mean to get NRMS and d values of 17.8 and 0.86. No information about the evolution of soil moisture behavior throughout the growing season is provided, this could help to give information about how the soil moisture behaves under different scenarios.

Discussion section. Lines 265-267. Could you explain the cause?

Discussion section. Lines 276-279. You say “…being that the potato crop development under the experimental plot's climatic conditions (Peruvian Altiplano) is not influenced by the irrigation lamina…, …season in the Peruvian Altiplano (December-March) with the vegetative period of the potato crop (November-April) contributes to adequate vegetative development when it is not deficient (drought); therefore, it has a direct impact on the agricultural calendar…”. Here I understand you want say there is no differences in yields between optimized and reduced irrigation? If so, do you agree that even when there is no difference in yields, there are differences in water use efficiency?

Discussion section. Lines 292-295. How did you determine these decreases? It sounds like trend analysis but this was not established at the beginning of the research.

Synthesis of discussion. There is no any practical recommendation in this section. It is just focused on making some summaries and rescuing some main ideas from results. My first impression is here any solution to any problem is shown. Sometimes I found this section some confused for example when the article says that the yield is not affected by irrigation.

 

General opinion about the paper. The title of the article is very general and ambitious. In the content one can find modeling, irrigation, climate change scenarios; therefore, these words should be incorporated in the title. Honestly, I do not find coherence among title, objective (in fact there is no any objective at the end of the introduction), methodology, results and discussion; at seem each section tries to present information with different goal. The paper idea is very interesting, mainly scenarios combined with modeling and irrigation but it is necessary to organize the information in results and discussion. In fact, in the discussion section, there is no any practical recommendation except in lines 348-352. Observing carefully, the paper does not give any specific solution. I suggest the paper be re-submitted integrating all these ideas I provide here. For the above, I reject the paper in the present form, my opinion is rejected with major changes.

Comments for author File: Comments.pdf

Author Response

"Please see the attachment."

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Introduction 

This section should be supported by more information related to potato yield and the negative effects of factors-related to climate changes (extreme temperature, drought,…)   

L35: add the following citation after the word 'productivity 

https://doi.org/10.1007/s10343-021-00590-2 

 

L41: add 'the' before 'rainfed' 

L48: change 'Adopting' to be "adopting"   

 

L61: add (.) after in agriculture [19] and delete (;) as well as correct therefore to be Therefore 

Materials and Methods  

This section prepared well. However, the soil used in the experiment should be clearly described well illustrating acidity, salinity degree and nutrient analysis 

 

Discussion 

This section lack an interpretation of drought and extreme temperature based on plant physiology. I suggested to review and cite the following articles   

https://doi.org/10.1007/s10343-022-00635-0

 

 

Author Response

"Please see the attachment."

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

The authors performed a field experiment about the impact of climate change on potato crop yield and assessed the effect by the AquaCrop model. The results showed that climate change generates moderate impacts on potato crop yields mainly due to the average reduction in precipitation. The manuscript is well written with detailed analysis. However, there are some concerns that need to be addressed before considering publishing.

 

1. The abstract section is not clear. The authors should make detailed description about the treatments and results.

2. In the “introduction”, the third paragraph mainly described about the “climate change” which may be put in first, along with “Global warming, precipitation and temperatures”. Some introduction about the assessment in crop yield response to climate changes should be described.

3. Some figures are not elegant, lacking of scale mark, like Fig. 2, 5, 7, 8.

4. Detailed description about the measurement of canopy coverage, biomass, and yield should be added, and these data may be provided or as supplementary materials.

5. The “Discussion” section should be expressed according to the “results” section.

Comments on the Quality of English Language

The English writing proficiency is still good, but further polishing and modification are still needed.

Author Response

"Please see the attachment."

Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors

The authors simulated potato growth and yield parameters under the Representative Concentration Pathway (RCP), RCP 4.5, and RCP 8.5 scenarios based on AquaCrop model in Peruvian Altiplano. The results show a good performance of the AquaCrop model in the calibration and validation, simulating the crop growth and yield parameters, although based on only one-year field experiment from 2017–2018. Overall, I suggest only minor modification is needed before acceptance. The comments are following:

1. In the introduction part, the authors should explain the reason why selecting AquaCrop model rather than other models.

2. In the 2.4, I suggest the authors introduce more details of model parameters setting. For example, how to define the water content of fresh potato in the aquacrop model.

3. Please check the format carefully before MS submission. For example, the font of “Representative Concentration Pathway (RCP), RCP 4.5, and RCP 8.5” is larger than other words in the abstract… 

Author Response

"Please see the attachment."

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

I finished the review on the paper “Evaluating the Yields of the Rainfed Potato Crop Under Climate Change Scenarios Using the AquaCrop Model in the Peruvian Altiplano”

 

Although several changes were carried out in the whole paper, I do not see significant improvements in results and discussion sections. First, in results I suggested to include the reasons for which obtaining these results; and strength it with various references. Also, authors need to take into account all the agronomic meaning of the information they have presented here. They have done some changes here, but they are minimal. Regarding to discussion, changes also have been minimal; as I said in previous review, I do not find any practical recommendation, It is just focused on making some summaries and rescuing some main ideas from results.

 

For the above I think the paper is not suitable for being accepted for publication yet.

Comments for author File: Comments.pdf

Author Response

"Please see the attachment."

Author Response File: Author Response.docx