Water Stress Index and Stomatal Conductance under Different Irrigation Regimes with Thermal Sensors in Rice Fields on the Northern Coast of Peru

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Dear Authors,

I have carefully reviewed your paper titled "Spatial Estimation of Crop Water Stress Index (CWSI) to Evaluate Water Status and Stomatal Conductance under Different AWD Irrigation Regimes from Thermal UAV Images in Rice Fields on the Northern Coast of Peru." The study addresses a crucial aspect of water stress in rice fields using thermal UAV images.

I have some constructive comments:

1. In the methodology flowchart (Figure 1), there seems to be a repetition in the connection between Canopy temperature (T_c) and Vapor Pressure Deficit (VPD) vs. (T_c-T_a). Please clarify and correct this in the flowchart.

2. On page 6, line 151, you mentioned, "The fertigation rate applied was 250-106-60." It would be helpful if you could provide an explanation or context for these values to enhance the readers' understanding.

3. It appears that you derived a single linear equation for six commercial areas, despite potential variations in radiometer temperatures for each field. Could you please explain the rationale for using a single linear equation for all fields?

4. In Figure 4, you presented scatter plots for various coverings such as aluminum, dry leaves, green leaves, expanded polystyrene, yellow cloth, black cloth, red cloth, green cloth, bare soil, and wet soil. Consider whether it is essential to include all these coverings, or if some could be omitted for clarity.

I appreciate your attention to these matters and believe that addressing these points will enhance the overall quality of your paper.

Author Response

Consulte el archivo adjunto.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Manuscript, entitled ^„ Spacial Estimation of Water stress index (CWSI) to evaluate water status and stomatal conductance under different AWD irrigation regimes from thermal UAVs images in rice fields on the northern coast of Peru^„. The findings of the study revealed that AWD irrigation resulted in higher water stress compared to CF irrigation. This allowed for the identification of areas with higher CWSI. Furthermore, there was a strong Pearson correlation (R) of 0.91 between CWSI and Gs. The CWSI and Gs maps generated in this study serve as valuable tools for efficiently monitoring rice zones and inducing controlled water stress in the crops. There are shortcomings and modifications that should be included in order to enhance the final manuscript for the readers.

Title

·        Title is long and should be modified.

·        Spacial Estimation of Water stress index (CWSI). Why special? CWSI is used since long time in estimate water status and stomatal conductance.

·        AWD, please do not abbreviation in the title?

 

Abstract

·        Line 17. Each plot? It is not clear. Please rephrase this sentence from line 17 to line 18?

·        More important results should be added in abstract.

Introduction

·         Line 62-63. These cameras allow for the capture of thermal images of the plant surface in a fast and efficient manner, without the need for direct physical contact. What do you mean about direct physical contact? Since the stress not only can be applied by water stress but by salinity and nitrogen stress which can increase the plant temperature.

·        Please highlight the novelty of this work since the several studies were done with CWSI , water stress and stomatal conductance?

 

Materials and Methods

·        Line 93-95. The study focused on comparing the  effects  of  different  irrigation  regimes,  specifically  alternating  wetting  and  drying (AWD) and continuous flooding (CF). please remove this sentence? It Is related to introduction section.

·        Remove table 3 and write the information of the table in the text.

·        Remove figure 3.

·        Line 177 to line 180 should not be added at the end of this section.

·        Figure 4 should be improved.

·        Line 231. Meteorological data should be presentenced since they are important to calculate CWSI.

·        Line 240 to line 271. Several studies presented the CWSI. Please shorted this section by added the references.

Results

·        Figure 5 should be improved; I cannot follow the data in the figure to compare with text.

·        In figure 10. Present only R².

 

Discussions

·        Please, write the practical applications of your work in a separate section, before the conclusions and provide your good perspectives?

Conclusions

·        Please write the limitation of this work.

Comments on the Quality of English Language

Minor editing of English language required

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

It is unclear the reason for using a drone with a thermal camera. You have not specified the radiometric precision of the camera you used, the best ones usually have a range of +/-5°C, this makes it very difficult to use them for multi-temporal work and therefore use the data as an absolute value. Furthermore, having carried out flights at completely different times and atmospheric conditions makes the use of these sensors even more complicated to obtain reliable temperature data.
Without further clarification it is not possible to use this data. The crop temperature value is probably due more to the ambient temperature than to any effect of the plant's stomatal mechanism.
The study is of excellent value regarding the part on environmental temperature and stomatal conductance, but for plant temperature you could use a portable thermal camera or leaf temperature sensors if you want to use the multi-temporal data as an absolute value.

Comments on the Quality of English Language

Minor editing of English language required

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

The authors improved the manuscript according to my comments. It can be accepted for publication.

Author Response

The reviewer accepted the article for publication.

Reviewer 3 Report

Comments and Suggestions for Authors

dear editor, dear authors,
I have already made my decision: rejected.
However it is possible to see the good will of the authors and the proposed corrections are ok, but the basic problems I had written earlier remain.
At this point the editor can decide whether to publish it or not, in case he wants to go ahead with the publication I can suggest at least to change the title by changing the sentence "from thermal UAVs images" with for example the following: "with thermal sensors".

Considering in fact that this is a good work, but that it cannot be done relying only or mainly on the thermal camera from drone (as it would seem by reading the title and abstract), changing the title and consequently also the abstract would be a different work and would make sense. If the editor agrees this could avoid having to re-submit the work and would reduce the publication time.

Comments on the Quality of English Language

no

Author Response

Consulte el archivo adjunto.

Author Response File: Author Response.pdf