Impact of the Covering Material on Drought Tolerance Responses and Soil Water Content in Two Cultivars of Young Blueberry Plants under Protected Cultivation

Round 1

Reviewer 1 Report

General Comments: This paper was well written and fairly straight forward with an understandable problem statement. I only have a few comments for the authors.

 

Discussion of Various Plant Variables: The authors report the results of various variables (vapor pressure deficit, photosynthetic photon flux density, soil water potential, stomatal conductance) under alternative coverings, no covering, and for two different blueberry cultivars without too much context as to why they are measuring these variables and why outcomes for these variables matter. This comment is primarily for readers of their study who want to know more about the potential benefits of coverings for blueberry production but who know little about these variables. For such readers, little may be gleaned from reading the manuscript. The manuscript would benefit from a definition of these variables and why measurement of such variables is important for determination of potential water savings from coverings in drought conditions. For example, on page 9, the authors report differences in stomatal conductance by covering as well by cultivar. Why is stomatal conductance measured and what do measured differences in stomatal conductance between coverings and between cultivars imply with regards to water savings and drought tolerance?

 

Page 5, Lines 205 - 208: The authors report differences in solar radiation and photosynthetic flux density for the two regions during the months of December and January. Why do these differences matter? How do differences in these two variables affect study results?

 

Page 13, “Conclusions”: The authors do not say anything about the relative costs of covering materials. Is the cost economical or prohibitive?

Author Response

Discussion of Various Plant Variables:  We added the information requested by the reviewer in the Introduction. 

Page 5, Lines 205 - 208:  Differences in climatic conditions that determine ETc between locations are very important, as results were not always the same for each location. We discussed the importance of these differences in the new version of the manuscript. 

Page 13, “Conclusions”: The authors do not say anything about the relative costs of covering materials. Is the cost economical or prohibitive?

We included information about the relative costs of protected cultivation in blueberries in the introduction and mentioned the importance of this conclusions.  

Reviewer 2 Report

Your experiment might be included important data, and your results might have a value to publish in Water. However, there were many problems before publication. You need major revision according to my suggestion. Moreover, I could not imagine revised version of your manuscript. Therefore, your manuscript needs re-review at revised version.

Moreover, I would like to indicate the concrete problems of your manuscript as following:

 

1. In the first paragraph of introduction, use of structures for the protection of blueberry was common. However, I thought that this method did not have to use at the region of cold climate. Therefore, you have to explain that this method is important for the cultivation in Chile.

 

2. You did not emphasize the novelty and originality of your experiment. I confirmed that there were many articles on the drought stress of blue berry. Especially, Balboa et al. [25] was an experiment conducted in your country. You must review many articles on the drought stress of blueberry, and clarify the general characteristics of blueberry to the drought stress. Also, you must emphasize the unsolved points from the survey of previous experiments. Through this process, you emphasize the originality of your experiment, and establish your hypothesis.

 

3. You must explain the reason why you selected the cultivations of Top Shelf and Blue Ribbon.

 

4. In general, measurements of water potential are twice (midday and predawn). You must explain the reason why you did not measure water potential at predawn.

 

5. Your design of results was not unified. You must unify all of figures and tables. The data of results were four treatments (Control, Netting, Woven and Plastic), two cultivars (Blue Ribbon and Top Shelf), and two sites (Linares and Traiguen). Moreover, statistical analysis between two sites was essential.

 

6. In Figure 5 and 7, you must show four treatments, two cultivars and two sites. Moreover, regression lines have to show for each treatment. Correlation coefficient and statistical analysis on the regression are also important. Furthermore, you should conduct ANCOVA among four cultivation.

 

7. In Figure 6, you must revise the word of “Raffia”.

 

8. In Figure 3, Table 1, 2 and 3, you must add the information on the number of individuals.

 

9. In discussion, there was no quotation of figure or table. You must add these quotations for feedback of your results. Your discussion was insufficient on the comparison of other articles of drought stress of blueberry. You should emphasize new finding by comparison of similar experiments. Moreover, you should discuss on the comparison of physiological characteristics between two sites.

 

10. In conclusion, you did not conclude the most effective treatment to mitigate drought stress of blueberry.

There was little problem on the quality of English language. On the revised version, please maintain the quality of English language.

Author Response

1. In the first paragraph of introduction, use of structures for the protection of blueberry was common. However, I thought that this method did not have to use at the region of cold climate. Therefore, you have to explain that this method is important for the cultivation in Chile. R: We added the importance of this technoloy in Chile in the introduction.
2. You did not emphasize the novelty and originality of your experiment. I confirmed that there were many articles on the drought stress of blue berry. Especially, Balboa et al. [25] was an experiment conducted in your country. You must review many articles on the drought stress of blueberry, and clarify the general characteristics of blueberry to the drought stress. Also, you must emphasize the unsolved points from the survey of previous experiments. Through this process, you emphasize the originality of your experiment, and establish your hypothesis. R: The whole discussion was edited, and new citations were also included to contextualize this study. 
3. You must explain the reason why you selected the cultivations of Top Shelf and Blue Ribbon. R. Added this information in the introduction. 
4. In general, measurements of water potential are twice (midday and predawn). You must explain the reason why you did not measure water potential at predawn. R: Some studies measure predawn water potential to indirectly estimate soil water status. In our study, we had soil water content probes to characterize the impact of the covering materials on soil desiccation. Also, we were interested in the impact of coverings on maximum plant water stress severity. In this context, several authors in many fruit crops (e.g., Larry Williams or Ken Shackel), have provided robust evidence for more than 20 years about the convenience of measuring plant water potential at midday rather than at predawn to estimate the highest severity of water stress during a particular day. For instance, one of the most recent articles, publisehd in the Agr. Wat. Mangament. provides SWP measures as the only indicator of plant water stress. (https://www.sciencedirect.com/science/article/pii/S0378377421000706)
5.  Your design of results was not unified. You must unify all of figures and tables. The data of results were four treatments (Control, Netting, Woven and Plastic), two cultivars (Blue Ribbon and Top Shelf), and two sites (Linares and Traiguen). Moreover, statistical analysis between two sites was essential. R: We cannot perfom any inferential test to compare both sites, as they do not have replicates. We only have one orchard in Linares and one orchard in Traiguén (one rep per location). This is why we show separate anova and mean separation tests for each location.  Also, when we had significant interactions, we did not analyze the simple effects. We indicated that in the text and tables. When the studied factors that did not interact with each other, we pooled the data sets and indicated this procedure in the text and tables. 
6. In Figure 5 and 7, you must show four treatments, two cultivars and two sites. Moreover, regression lines have to show for each treatment. Correlation coefficient and statistical analysis on the regression are also important. Furthermore, you should conduct ANCOVA among four cultivation. R: Figure 5: There was no relationship between VPD and SWP in Traiguen, regardless of the cover treatment. This is why that information was no included. In Linares, regression lines were significant for all coverings except for plastic. The ANCOVA showed similar regression coefficients for Control, Netting, and Woven. Therefore, only one regression is reported in the revised version of the manuscript. Figure 7: the requested information and analyses were included. 
7. In Figure 6, you must revise the word of “Raffia”. R: This is now corrected.
8. In Figure 3, Table 1, 2 and 3, you must add the information on the number of individuals. R: We added this information in all Figures and Tables. 
9.  In discussion, there was no quotation of figure or table. You must add these quotations for feedback of your results. Your discussion was insufficient on the comparison of other articles of drought stress of blueberry. You should emphasize new finding by comparison of similar experiments. Moreover, you should discuss on the comparison of physiological characteristics between two sites. R: We edited the discussion as suggested. 
10. 10. In conclusion, you did not conclude the most effective treatment to mitigate drought stress of blueberry. R: This was included. 
11. There was little problem on the quality of English language. On the revised version, please maintain the quality of English language. R: English was improved in the whole manuscript. 

Reviewer 3 Report

The manuscript mainly involves the effect of various types of coverings on plant water relations of two new blueberry cultivars in recently-planted orchards under two temperate climate types. This research is of great significance for the effective use of soil water by fruit trees in arid areas. The method adopted in manuscript are reasonable.. However, there are some details that should be addressed to make the manuscript more academic.

 

Title : Impact of the covering material on water savings and drought tolerance in two cultivars of young blueberry plants under protected cultivation. In this title, water savings and drought tolerance are not completely inconsistent with the research content in this paper, please improve it. 

Abstract : The purpose of the study needs to be further clarified. How is soil water treated?

Is the soil of the two orchards the same texture？Ψstem and gs: symbols that appear for the first time need to explain their full meaning. Lack of two different Cultivars of research results.

Materials and Methods : What is the dry bulk density of the soil? Please add the field water capacity and dry bulk density of the soil in the Materials and Methods section. Where is the capacitance sensor on the droplet? And how are the drip irrigation belts arranged? There's no Ds in the formula in the line 152-155.

Results: The study was conducted under drip irrigation for two consecutive seasons (2018- 2019 and 2019-2020), however, the time writing in different graphs and tables is inconsistent, please check them. Is the data measured in 2018-2019 season or 2019-2020 season in Figure 3? Also explain why some charts use 2018-2019 season data, some use 2019-2020 season data, and some use both years?

What Cultivar of blueberries are listed in the Linares orchard in the table 1-3？

 

Comments for author File: Comments.pdf

Author Response

1. Title : Impact of the covering material on water savings and drought tolerance in two cultivars of young blueberry plants under protected cultivation. In this title, water savings and drought tolerance are not completely inconsistent with the research content in this paper, please improve it.  R: We edited the title.
2. The purpose of the study needs to be further clarified. How is soil water treated? We edited the abstract as suggested.
3. Is the soil of the two orchards the same texture？R: We added more information about soil characteristics in M&M.  Ψstem and gs: symbols that appear for the first time need to explain their full meaning. Lack of two different Cultivars of research results. R: Edited as suggested. 
4. Materials and Methods : What is the dry bulk density of the soil? Please add the field water capacity and dry bulk density of the soil in the Materials and Methods section. Where is the capacitance sensor on the droplet? And how are the drip irrigation belts arranged? There's no Ds in the formula in the line 152-155. R: All these aspects were included or edited, as suggested. 

5. Results: The study was conducted under drip irrigation for two consecutive seasons (2018- 2019 and 2019-2020), however, the time writing in different graphs and tables is inconsistent, please check them. Is the data measured in 2018-2019 season or 2019-2020 season in Figure 3? Also explain why some charts use 2018-2019 season data, some use 2019-2020 season data, and some use both years? R: We tried to measure in both seasons, but some measuring devices were only available for the second season. This is why some Figures and Tables only show data for 2019-2020. 

6. What Cultivar of blueberries are listed in the Linares orchard in the table 1-3？There was no cultivar by cover interaction in tables 2 and 3. This is why we pooled the data for both cultivars to indicate differences between covers. In Table one, we only measured in one block, this is why we also reported simple effects. 

 

Round 2

Reviewer 2 Report

Your manuscript was improved according to my suggestion. Moreover, I agreed your argument for my comments. Therefore, I decided that your submission was acceptable.