Thermography as a Tool to Assess Inter-Cultivar Variability in Garlic Performance along Variations of Soil Water Availability
Round 1
Reviewer 1 Report
remotesensing-906928
review for “Thermography as a tool to assess inter-cultivar variation in garlic performance along gradients of soil water availability”. This manuscript deals to calculate and calibrate soil water availability for yield production in farm scale. The manuscript is well designed, well-presented and the paper is basically correctly written. I recommend the minor revision. However, there are only some minor issues where are listed below:
L12: please add region or area after “Mediterranean”.
L20: add “s” to content.
Table 1: it is better to explain the aster items below the table.
Author Response
Response to Reviewer 1:
Review for “Thermography as a tool to assess inter-cultivar variation in garlic performance along gradients of soil water availability”. This manuscript deals to calculate and calibrate soil water availability for yield production in farm scale. The manuscript is well designed, well-presented and the paper is basically correctly written. I recommend the minor revision. However, there are only some minor issues where are listed below:
Dear reviewer, thank you very much for your kindly revision and feedback on this article. Please find below the response to your suggestions, which has been added to the new version of the manuscript. The lines provided in the response to your suggestions and comments corresponds to the clean version of the revised manuscript, without the track changes. Please note that the references and citation number have changed from number [52] onwards due to the inclusion of a new reference.
- L12: please add region or area after “Mediterranean”.
We agree. The word “region” has been added after “Mediterranean”. See it on line 12 of the revised manuscript.
- L20: add “s” to content.
We agree. The letter “s” has been added to “content” See it on line 20 of the revised manuscript.
- Table 1: it is better to explain the aster items below the table.
We agree. Now the aster items are below the Table 1 (see line 160). The same has been done for Table 4 (line 264) and Supplementary Table 1 (line 444).
Author Response File: 
Author Response.pdf
Reviewer 2 Report
In the title and in the paper the authors refer to gradients soil water to describe the VWCs variation available on the experiment sites. I think the term gradient must be changed. It refers usualy to water content depth variation in the soil. I would rather use variations instead of gradients
Line 5 “…Which causes economic losses…”
Line 50, please specfify “infrared thermal imaging”
Line 68 “… This induces an additional…”
Line 72 “the assessment and understanding of inter-cultivar variability of garlic in response to limiting environmental conditions, and the selection of the best performing genotypes…”
The natural resources are limited; the environmental conditions are extremely stressful for plants… please modify the sentence
Line 74 “…for its adaptation to future environmental conditions linked to climate changes…”
Line 79 :”… models to environmental conditions. It will improved efficiency in maximizing yields and develop effective mitigation and adaptations tools in garlic…”
Line 85 :”… where two continuous predictors (Cp of bulb production, CWSI and soil volumetric water content (VWCs)…” two or three predictors ?
Line 96 : “…with strong thermal oscillations…” please give range…
Line 97 : “…Historical average annual precipitation and temperature are ca. 500 mm and 11.8 ºC respectively…” references ?
Line 105 : “…Historical average annual rainfall is between 440 and 490 mm and the average annual temperature is around 14 ºC…” references ?
Line 110 : please, indicate that you consider that the soil texture and chemical characteristic are 1/ considered as constant or almost constant or… 2/ have been measured … please indicate the season/month
Line 115 : sun radiation
Line 149, I would prefer garlic varieties instead of garlic cultivars
Line 157, Table 1, center text in the columns
Line 171, Table 2, modify columns width so that you avoid line break
Line 174 2.3. Crop water stress index (CWSI), final bulb biomass and bulb diameter measurement
Line 180 please indicate 1/measurement distance between camera/sensor and leaves 2/ estimate the surface of the leaves involved in the measure
Line 181 :”… Thermal images were taken for every plant within each plot at least two or three times throughout the bulbing phase…” please precise measurement interval
Line 184 :”… average leaf temperatures were calculated by selecting representative areas of the sample leaves (Tleaf) and…”
Please give more indications and introduce a thermal image in the paper
Line 202 : “…Representative bulb biomass obtained by the models was calculated…”
Line 216 3. Results and discussion
I wonder if it isn’t more logic to switch 3.1 (measurements, presentation of VWCs and CWSI effects) and 3.2 (models results in accordance with observation of VWCs and CWSI effects on measurements…)
Line 272 these graphs combine the plantations (garlic varieties) of the three sites. it would be helpful to differentiate the three sites using round and triangular square markers
Line 324 on my version of the article the graphs of figure 3 are over the table
The graphs represents models results. Where the bulb biomass variations (for one VWCs level) come from ? CWSI variation ?
Some superposed results for garlic varieties cannot be used / read on the graph
Author Response
Response to Reviewer 2:
Dear reviewer, thank you very much for your kindly revision and feedback on this article. Please find below the response to your suggestions, which has been added to the new version of the manuscript. The lines provided in the response to your suggestions and comments corresponds to the clean version of the revised manuscript, without the track changes. Please note that the references and citation number have changed from number [52] onwards due to the inclusion of a new reference.
- In the title and in the paper the authors refer to gradients soil water to describe the VWCs variation available on the experiment sites. I think the term gradient must be changed. It refers usualy to water content depth variation in the soil. I would rather use variations instead of gradients
We agree. The title has been slightly changed and now the word “gradient” has been replaced by “variations”. See it on lines 2-4 of the revised manuscript.
- Line 5 “…Which causes economic losses…”
We agree. The word “poses” has been replaced by “causes”. See it on line 35 of the revised manuscript.
- Line 50, please specfify “infrared thermal imaging”
We agree. The word “infrared” has been added before “thermal imaging”. See it on line 50 of the revised manuscript.
- Line 68 “… This induces an additional…”
We agree. The word “poses” has been replaced by “induces”. See it on line 68 of the revised manuscript.
- Line 72 “the assessment and understanding of inter-cultivar variability of garlic in response to limiting environmental conditions, and the selection of the best performing genotypes…” The natural resources are limited; the environmental conditions are extremely stressful for plants… please modify the sentence
Thank you for your suggestion. Now, the sentence has been changed to stress the point that the environmental conditions are already limiting, and we should focus on the existing cultivars to find short-term solutions to the current situation. Please see the modification of the sentence on lines 72-74 of the revised manuscript.
- Line 74 “…for its adaptation to future environmental conditions linked to climate changes…”
We agree. “Linked to climate changes” has been added at the end of the sentence. See it on line 75 of the revised manuscript.
- Line 79 :”… models to environmental conditions. It will improved efficiency in maximizing yields and develop effective mitigation and adaptations tools in garlic…”
We agree. We have modified the sentence according to your suggestion. See it on line 80 of the revised manuscript.
- Line 85 :”… where two continuous predictors (Cp of bulb production, CWSI and soil volumetric water content (VWCs)…” two or three predictors ?
Actually, there are two continuous predictors (CWSI and VWCs) and a categorical predictor (Cultivar) in the studied models. Now the sentence has been modified to clarify this aspect. See it on line 87 of the revised manuscript.
- Line 96 : “…with strong thermal oscillations…” please give range…
- Line 97 : “…Historical average annual precipitation and temperature are ca. 500 mm and 11.8 ºC respectively…” references ?
- Line 105 : “…Historical average annual rainfall is between 440 and 490 mm and the average annual temperature is around 14 ºC…” references ?
Thank you for your suggestion of these three points. The range of thermal oscillations (lines 97-99) and the references where the historical climate data have been added (line 100 and line 108). Please note that now the citation number have changed due to this new reference.
- Line 110 : please, indicate that you consider that the soil texture and chemical characteristic are 1/ considered as constant or almost constant or… 2/ have been measured … please indicate the season/month
Soil analyses were carried out before the establishment of the assay, but determinations from previous years show very constant inter-annual values. See lines 112-113.
- Line 115 : sun radiation
We agree. The word “sun” has been added before “radiation”. See it on line 118 of the revised manuscript.
- Line 149, I would prefer garlic varieties instead of garlic cultivars
We use the term “cultivar” since it is used as a group of plants produced and maintained by horticulturists but does not produce “true seed” and is vegetatively propagated, as it is the case of garlic; whereas a variety usually produces “true seed”
- Line 157, Table 1, center text in the columns
We agree. The text is now aligned within the same column. See line 160 of the revised manuscript.
- Line 171, Table 2, modify columns width so that you avoid line break
We agree. The text from each row is now within the same line. See line 174 of the revised manuscript.
- Line 174 2.3. Crop water stress index (CWSI), final bulb biomass and bulb diameter measurement
We agree. The word “measurement” has been added at the end of the section title. See it on line 177 of the revised manuscript.
- Line 180 please indicate 1/measurement distance between camera/sensor and leaves 2/ estimate the surface of the leaves involved in the measure
- Line 184 :”… average leaf temperatures were calculated by selecting representative areas of the sample leaves (Tleaf) and…”Please give more indications and introduce a thermal image in the paper
We agree. Based on your suggestions on these two points and the comments of the other reviewers we have added more text in this section to clarify the methodology carried out to calculate CWSI. Now, the distance between the camera and the leaves is provided (line 183). Besides, we have added an image with one visual RGB photograph and its corresponding thermal image to show how we obtained the temperatures of the references and the leaves in the processing software. In this image you can observe an example where leaf surfaces were selected, corresponding to the youngest fully expanded leaves (see the image on line 201 and the clarification in the text on line 192)
- Line 181 :”… Thermal images were taken for every plant within each plot at least two or three times throughout the bulbing phase…” please precise measurement interval
More information has been added on this aspect at section 2.3. The measurement interval was not constant across the different experimental assays since the growth development was clearly affected by environmental conditions. Thus, the measurement interval was based on the growth development, mainly on the number of leaves. This aspect has been clarified in the text (lines 185-188).
- Line 202 : “…Representative bulb biomass obtained by the models was calculated…”
In this sentence we have decided to keep the word “used” instead of “obtained” since we refer to the measured bulb biomass, which were used to test the goodness of fit of the tested models. In the case of the bulb biomass obtained in the models we refer to “Bulb biomass-estimated marginal means” (line 223).
- Line 216 3. Results and discussion
I wonder if it isn’t more logic to switch 3.1 (measurements, presentation of VWCs and CWSI effects) and 3.2 (models results in accordance with observation of VWCs and CWSI effects on measurements…)
We agree that usually it seems more logical to present the observations before the model results. However, in the case of this manuscript, we want to focus on the reliability of CWSI as a tool to predict bulb biomass production and for cultivar screening. That is the reason why we decided to start with the model results to evaluate the robustness of thermal imaging followed by the inter-cultivar differences. Anyway, if you and/or the editor still consider that is necessary to change the order of these sections we are open to apply this modification.
- Line 272 these graphs combine the plantations (garlic varieties) of the three sites. it would be helpful to differentiate the three sites using round and triangular square markers
We agree. The previous graph has been replaced by a new one in which the assays are differentiated by different shapes (line 283)
- Line 324 on my version of the article the graphs of figure 3 are over the table
Thank you for your observation. This figure has been relocated to see the table (line 341). Please let us know if the problem persists.
- The graphs represents models results. Where the bulb biomass variations (for one VWCs level) come from ? CWSI variation? Some superposed results for garlic varieties cannot be used / read on the graph
In Figure 3 (line 341), the bulb biomass variations at the same VWCs level are the confidence intervals of the Bulb biomass-estimated marginal means (B-EMMs). In some cases, despite these B-EMMs are different, the confidence intervals of different cultivars are superposed.
Author Response File: Author Response.pdf
Reviewer 3 Report
The paper is well-written and I enjoyed reading it throughout. However, I am not sure if the content is very appropriate for a 'Remote Sensing' journal. This paper would have been a great match to a journal like "Computers and electronics in agriculture" or similar. For publishing in Remote Sensing, the paper requires modification to include more content related to data acquisition, image processing, imagery type etc. in the method. Also, the introduction should highlight more on the use of remote sensing/thermal imaging in the similar context.
On a separate note, I feel the climate change aspect could be more boldly incorporated into the manuscript.
Otherwise, it's a really good and interesting paper..I just feel it could be submitted to a more appropriate journal.
Author Response
Response to Reviewer 3:
Dear reviewer, thank you very much for your kindly revision and feedback on this article. Please find below the response to your suggestions, which has been added to the new version of the manuscript. The lines provided in the response to your suggestions and comments corresponds to the clean version of the revised manuscript, without the track changes. Please note that the references and citation number have changed from number [52] onwards due to the inclusion of a new reference.
- The paper is well-written and I enjoyed reading it throughout. However, I am not sure if the content is very appropriate for a 'Remote Sensing' journal. This paper would have been a great match to a journal like "Computers and electronics in agriculture" or similar. For publishing in Remote Sensing, the paper requires modification to include more content related to data acquisition, image processing, imagery type etc. in the method. Also, the introduction should highlight more on the use of remote sensing/thermal imaging in the similar context.
Thank you very much for your suggestion about the journal. We agree that “Computers and electronics in agriculture" would match with the content of this manuscript. In the case that this article is not finally accepted here we will consider publishing it in that or a similar journal. However, we consider that this manuscript can be published as open access in the section of “Remote Sensing in Agriculture and Vegetation” in this journal. We have read some articles in this journal covering similar aspects. Besides, we agree with you that it was necessary to include more content on the methodology. As you can see in the revised manuscript, we have modified the section of “2.3. Crop water stress index (CWSI), bulb biomass and bulb diameter measurement” (line 177). Now, more detailed information of the methodology carried out along with an informative image has been added.
About the use of remote sensing/thermal imaging in the similar context we provided some examples within the lines 46 to 58. However, this type of studies is still lacking on garlic. To the best of our knowledge, only one attempt besides the research carried out in our lab has been done to the date on remote sensing research on garlic, that is the work of Campoy et al., 2019, which is cited in the text with the reference number [89], line 699.
- On a separate note, I feel the climate change aspect could be more boldly incorporated into the manuscript.
We agree with you that climate change should be a key aspect on agricultural research and cultivar selection. In fact, we have mentioned the climate change effects on agriculture in the introduction (see lines 11; 15; 34; 38; 45; 64 and 75). However, in our experimental design we only could directly control the irrigation and, thereby, the soil water availability. Henceforth we consider that the results obtained and the discussion derived from them should be extrapolated to climate change effects with caution, since other climatic conditions (CO2 concentration, temperature, VPD, etc) affected by climate change could not be considered as controlled factors in our experimental assays. Nonetheless, we agree with you and we have added some sentences to refer to climate change in the section of Results and Discussion (see line 338-339) and in Conclusions (see line 407-408)
- Otherwise, it's a really good and interesting paper..I just fee-l it could be submitted to a more appropriate journal.
Thank you very much for your kindly appreciation. I hope we have enhanced and adapted the manuscript enough to be accepted in this journal. If not, we will consider sending it to others based on your suggestions.
Author Response File: Author Response.pdf
Reviewer 4 Report
The experimental study presented in this paper is based on a detailed statistical analysis of the data acquired to define an empirical model between bulb weight and observed variables (VWC and CWSI). To this extent the study is not particularly innovative, but as authors claim, there are not many studies of this kind on garlic. This is probably due to the particular foliage structure which obviously influences vapour exchange with atmosphere in the transpiration process. This could be an additional explanation for the lower performance of CWSI compared to VWC.
Although the study is complete and described with accuracy, some more information about the structure of epigeal biomass (including examples of thermal pictures) would support a complete understanding of the investigations carried out.
About CWSI: a table with values of reference dry and wet temperatures in the different treatments would be of interest.
Fig.3 at page 12 in the PDF version is covering a table.
Author Response
Response to Reviewer 4:
Dear reviewer, thank you very much for your kindly revision and feedback on this article. Please find below the response to your suggestions, which has been added to the new version of the manuscript. The lines provided in the response to your suggestions and comments corresponds to the clean version of the revised manuscript, without the track changes. Please note that the references and citation number have changed from number [52] onwards due to the inclusion of a new reference.
- The experimental study presented in this paper is based on a detailed statistical analysis of the data acquired to define an empirical model between bulb weight and observed variables (VWC and CWSI). To this extent the study is not particularly innovative, but as authors claim, there are not many studies of this kind on garlic. This is probably due to the particular foliage structure which obviously influences vapour exchange with atmosphere in the transpiration process. This could be an additional explanation for the lower performance of CWSI compared to VWC.
Thank you for your comment. We agree with you that this is an empirical model which have been addressed in similar ways in other crops. Nonetheless, the novelty of this article relies on the capacity of CWSI to predict bulb production with a low-cost effective tool. This is particularly innovative in bulb plants. Besides, with a few and cost-effective measured variables, CWSI and VWCs, the models could differentiate the production capacity of different cultivars under different environmental conditions, which can be useful for cultivar selection and screening. About the garlic foliage structure, we agree with you that could influence on the transpiration exchange and its interaction with the environment. Based on your comments it would be interesting to test in the future how foliar structure influences on CWSI performance. Withal, with further and future research, thermal imaging may become an important tool for garlic phenotyping and this work could serve as a base for future improvements.
- Although the study is complete and described with accuracy, some more information about the structure of epigeal biomass (including examples of thermal pictures) would support a complete understanding of the investigations carried out.
Thank you for your kindly comment. We agree. Based on your suggestions and the comments of the other reviewers we have added more text in this section to clarify the methodology carried out to calculate CWSI. Now, the distance between the camera and the leaves is provided (line 183). Besides, we have added an image with one RGB photograph and its corresponding thermal image to show how we took the temperatures of the references and the leaves in the processing software. In this image you can observe an example of which leaf surfaces were selected, that corresponds to the youngest fully expanded leaves (see the image on line 201 and the clarification in the text on line 192)
- About CWSI: a table with values of reference dry and wet temperatures in the different treatments would be of interest.
Thank you for your suggestion. The temperature of the reference surfaces does not vary across treatments but rather on the actual weather conditions at the time that thermographic data were recorder. To provide additional information on this point we include the mean +- S.D of these dry and wet references for the whole experiment. See lines 193-194 of revised manuscript.
- 3 at page 12 in the PDF version is covering a table.
Thank you for your observation. This figure has been relocated to see the table (line 341). Please let us know if the problem persists.
Author Response File: Author Response.pdf
Round 2
Reviewer 3 Report
Substantially improved. I agree with the authors' response. Accept after minor proof and grammar check. Thank you!
