Effect of Application Techniques on Spray Quality Optimization in Sweet Pepper Cultivation in Protected Environments

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The submitted paper evaluates the effects of reducing the spray rate and using pneumatic spraying (with and without electrostatic charges) on deposition levels, spray coverage, and pesticide losses to the soil in sweet pepper cultivation grown in a greenhouse. The relevance of this study lies in addressing common challenges faced in the application of pesticides to horticultural crops in protected environments, such as greenhouses. These challenges include low on-target deposition, uneven pesticide distribution, excessive spray volumes greater than those required for effective application, and environmental contamination.

The manuscript is well written and the results are very interesting. Below are some comments and questions that arose during the reading. I would appreciate it if the authors could address them.

• Although electrostatic attraction (in PAEA) appears to be an additional mechanism that further optimizes deposition and coverage on the abaxial surface, it appears that air assistance influences deposition on the abaxial surface more than electrostatic attraction. Do the authors agree with my opinion?
• The authors mention that meteorological conditions (temperature, relative humidity) were not fully controlled in the greenhouse, and therefore canopy characteristics varied between seasons. Could you provide even a range of meteorological conditions for 2019 and 2020?

Author Response

Responses to reviewer 1's questions 
The average deposition values measured on the abaxial surface of the inner 
and outer leaves between the PAEA and PAA treatments showed no significant 
differences. Notably, the highest spray deposition values on the abaxial surface, 
particularly during the 2020 season, were observed in the pneumatic sprayers 
treatments. 
Unfortunately, we could not retrieve the all weather data during the experiments. 
Although we had this partial information, we believe it would differ significantly from the 
weather conditions inside the greenhouse.

 

 

Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

Please see the attached report

Comments for author File: Comments.pdf

Author Response

Responses to reviewer 2's questions 
A sentence with the importance, area, and production of sweet peper has been 
Included. (lines 42-48) 
The problem and aims of the study, in more detail, were inserted in the 
Introduction. (lines 82-98)

All devices examined in this study are currently available for purchase. (line 131)

Some references were inserted in the text. The methods without a reference are due to the specific nature of the study.

The discussion was improved and is highlighted in red in the text. (lines 492-498)

The methodologies not mentioned were developed according to the study's specifics.

All the sprayer devices are applied commercially, usually by small vegetable producers.

The discussion was improved and is highlighted in red or blue in the text.

The conclusion provides answers aligned with the study's objectives. A new paragraph at the end of the introduction suggests further research on pesticide control efficiency.

All the information above was corrected in the text. The references and citations were carefully checked. 

Author Response File: Author Response.docx

Reviewer 3 Report

Comments and Suggestions for Authors

This is an interesting paper in the field of agriculture engineering arising to optimize the pesticides application by complementary techniques, namely air assistance combined with electrical charge transfer towards solution droplets during irrigation process. As target plant the sweet pepper has been chosen, since it is of special interest for brazilian agriculture and population nutrition.

The main objectives were to evaluate the effects of spray rate, spray coverage and ground loses. The main application techniques were: standard farmer hydraulics, reduced volume hydraulics, pneumatic with air and electrostatic assistance and pneumatic with air assistance.

The state-of-the-arts in this field is up-dated into a short introduction by presenting the main contribution of 15 works out of a total of 34 references.

The original contribution is presented in detail in the following two sections. The part devoted to materials and methods contains data on characterization of the experimental area, design and preparation treatments. 

The equations used for quantification of leaf area index, of the depositions and losses to the ground, evaluation of spray coverage and statistical analysis are discussed for two crop seasons in 2019 and 2020. It was established that spaying coverage is determined by a series of factors, such as: spray nozzle, droplet size, work pressure and the interaction between sprayed droplets and the target surface. It was suggested that the pneumatic treatment using electrostatic charges can be used as alternative for improving the application quality on abaxial leaf surface.

Generally, the text is well written. However, some corrections are still need.

For instance, at line 50, irregular must be written with small letter.

A free space must be at line 105 for "and spraying".

The numbering of sections after 2.4 must be corrected, as 2.4 is twice.

At line 196 the number of equation (2) should be moved from next line.

Moreover, the concentration of analyte should be written inside parentheses [C]. 

Therefore, I recommend these corrections to be made before publication, and the final decision is for "minor revision".

 

Author Response

Responses to reviewer 3's questions

All the suggestions were accepted and the corrections made.

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

Please see the report of the revision 

Comments for author File: Comments.pdf

Author Response

Cover Letter Round 2

 

The authors improved many parts in their manuscript and responded to some comments, but there are some other comments they did not improve, and I do not know the reason as follows:

Ÿ Where is the discussion of the paragraph (from line 461-481)?

The discussion was improved: Lines 466-469 and lines 478-480

Ÿ The conclusion should have a summary of the results of the study and also contain what they should study in the future related to their research.

The conclusion was revised to summarize the results and included a proposal for future research at the end.

Ÿ The authors should follow the instructions of the MDPI journals in writing the reference section and follow their style in writing.

The reference section now follows MDPI instructions.

Ÿ Many references need to be updated

Some old references were removed. Two updated references were added to the discussion section (lines 670-673). All the references kept are essential to this paper.

Ÿ Some references were written in a language other than English?

References that were written in a language other than English have been removed.

Ÿ In my opinion, the section of reference was written carelessly.

All references were checked and are following MDPI rules/instructions.

Author Response File: Author Response.docx