Control of Gas Emissions (N₂O and CO₂) Associated with Applied Different Rates of Nitrogen and Their Influences on Growth, Productivity, and Physio-Biochemical Attributes of Green Bean Plants Grown under Different Irrigation Methods

Round 1

Reviewer 1 Report

1. In the figure No. 2 it is not explained, what the vertical bars indicate;
2. In the table No. 7 significant differences between the treatments are not marked (asterisk or different letters);
3. I recommend not to use old literature sources;
4. I advise splitting the discussion into smaller chapters.

Author Response

Review Report Form 1

Comments and Suggestions for Authors

1. In the figure No. 2 it is not explained, what the vertical bars indicate;

This figure is a display of the data in Table No. 6, which is the same data and was placed for further clarification only, and therefore it was discussed when discussing Table No. 6

2. In the table No. 7 significant differences between the treatments are not marked (asterisk or different letters);

No statistically significant differences between treatments (asterisk or different letters) were marked in Table No. 7 because these values are outside of arithmetic operations and equations, and by searching in the relevant research, it was found that no statistically significant differences are placed

3. I recommend not to use old literature sources;

The references were reviewed and it was found that the old references were used in materials and methods, and this is possible to use in this case

4. I advise splitting the discussion into smaller chapters

This recommendation has been taken seriously and the discussion that needs to be broken down has already been broken down into smaller chapters

Author Response File: Author Response.pdf

Reviewer 2 Report

The authors presented a very interesting research problem in their work. Nevertheless, the presentation presented in this article requires corrections and additions. 

• The authors often use the Egyptian unit of area (feddan), but in part of the article they use the commonly known unit of hectare. The units used should be standardized in the article.
• cited FAO data (lines 49,50) are for what year?
• this same question for cultived area in Egypt (lines 53, 54)
• The article was written in 2021 so writing "... during the coming years till 2020" (lines 64,65) is inappropriate. 
• I do not agree with "One of the suggested strategies for optimizing irrigation scheduling is adopting modern irrigation systems ..." (line 69) It is correct to use the term "increasing efficiency" instead of "... optimizing irrigation scheduling" 
• The duration of the experiments is presented in Table 1 in an incomprehensible and incorrect way. The caption under the table shows that the experiment started in February and ended in December. Why are the results of observations only for 16 weeks listed in Table 1? Moreover, I suggest using the term "growing season" 
• practices and cultivations (lines 107,108) are recommended by the Ministry of Agriculture of which country? 
• The authors write (line 112) that fertilizers were applied together with irrigation (this process is called fertigation), or in each case? Did this also apply to the fertilization described in line 109 (soil preparation)? 
• How was the "recommended dose" (line 116) determined, why was there no chemical testing of the substrate soil? 
• The description of irrigation systems is very laconic and needs to be supplemented. The irrigation control system, the size of irrigation doses and fertigation doses as well as the times/terms of their implementation are not presented. 
• A description of the surface irrigation system has not been presented. The content contained in this part concerns the description of all the experimental plots. 
• My serious concern is the experiment scheme presented in Fig. 1. It shows that the experimental plots are very close to each other and therefore there is a very high probability that neighboring experiments will interact with each other. 
• I was very surprised to receive the quotation from the literature on the calculations of evapotranspiration (lines 139, 140). Item [37] concerns "The state of food insecurity ..." 
• A similar situation occurs with the WUE (lines 171,172) where reference is made to "World review livestock production ..." [49]. 
• Taking into account that we use the SI system, in which 1 cm = 10 mm, it is interesting how the authors obtained such high accuracy of plant height measurements presented in many places in the work, including line 199. 
• The averaging of the leaf area value used by the authors makes sense, while specifying the average value of the number of leaves is not (lines 200, 202, others) 

Technical Notes:

• In Figure 2 there is no description of the y axis (units and description), no "b" designation, and no "c" drawing / diagram at all.
• mark of sq meter in line 53 and sq cm in line 228
• What is a "2.2 Experimental design" in line 113 ?

Author Response

Review Report Form 2

 (Round 1)

Comments and Suggestions for Authors

The authors often use the Egyptian unit of area (feddan), but in part of the article they use the commonly known unit of hectare. The units used should be standardized in the article.

Units used in the manuscript have been standardized

An feddan (fed.) and a hectare have been converted to acre (acre = feddan)

Cited FAO data (lines 49,50) are for what year?

These stats are for 2019 and have been added to the paragraph

As reported by FAO [7], the total worldwide cultivated area of green beans is 1,649,711 hectares, producing 26,981,784 tons in 2019.

This same question for cultivated area in Egypt (lines 53, 54)

These stats are for 2020 and have been added to the paragraph

The cultivated area reached about 41.5 thousand feddans (feddan = 4200 m2 and hectare = 2.4 feddans), with a production of about 170 thousand tones in 2020 [10].

The article was written in 2021 so writing "... during the coming years till 2020" (lines 64,65) is inappropriate. 

Revised and amended until 2030

An initiated strategic program for reclaiming 1.4 million hectares of desert is being executed during the coming years till 2030 [18].

I do not agree with "One of the suggested strategies for optimizing irrigation scheduling is adopting modern irrigation systems ..." (line 69) It is correct to use the term "increasing efficiency" instead of "... optimizing irrigation scheduling"

Thank you very much for this recommendation and it was accepted 

The maximization of irrigation water use efficiency will be contingent upon developing efficient water delivery systems and increasing efficiency

The duration of the experiments is presented in Table 1 in an incomprehensible and incorrect way. The caption under the table shows that the experiment started in February and ended in December. Why are the results of observations only for 16 weeks listed in Table 1? Moreover, I suggest using the term "growing season" 

The comment was amended below the table so that the trial began in February and ended in June. So the results of the 16-week monitoring were only. The term studied season has been modified to growing season

* I would like to mention: Weekly averages have been placed in the table for ease of displaying the data

*Cultivation date started on 15th and 21st February during the two growing season, respectively, and the experiment ended at the middle of June. **RH means Relative Humidity, ***SRAD means Solar Radiation (MJ/m2/day), ETo = Evapotranspiration (mm/day).

Practices and cultivations (lines 107,108) are recommended by the Ministry of Agriculture of which country? 

Thank you for the recommendation. It has been modified to: By the Egyptian Ministry of Agriculture

All other agricultural practices of cultivation were performed as recommended by the Ministry of Agriculture, Egypt [36].

The authors write (line 112) that fertilizers were applied together with irrigation (this process is called fertigation), or in each case? Did this also apply to the fertilization described in line 109 (soil preparation)?

The first super phosphate fertilizer dose was added only before planting and before laying the irrigation lines, as it was applied directly into the soil, while the rest of the fertilizer was injected into the irrigation system (fertigation) during the growing season.

How was the "recommended dose" (line 116) determined, why was there no chemical testing of the substrate soil?

The recommended dose was determined based on the recommendations of the Ministry of Agriculture, Egypt, as previously described in the previous paragraph

I would like to mention: that Egyptian crops depend on total fertilization due to the lack of organic matter in the soil and the lack of soil fertility due to drought conditions and the scarcity of rain.

The description of irrigation systems is very laconic and needs to be supplemented. The irrigation control system, the size of irrigation doses and fertigation doses as well as the times/terms of their implementation are not presented. 

This was explained in the manuscript in many paragraphs, for example:

=====================================================================

2.3 Irrigation systems

2.3.1 Drip irrigation

Manifold lines were 32 mm diameter, polyethylene (P.E.) pipe used to supply laterals (drip lines) with the irrigation water. Drip tubing (type GR, 16mm diameter), with in-built emitters at 0.3m cm spacing, was used (delivering of 4 L per hour), the long of the drip line was 30 meters, one drip line was placed on each rows, 2 Bar pressure was maintained at drip tubing, the water source used was a river, and the water was transferred by the control station of the farm. The experi-mental plot had a flowmeter as shown in the Figure, 1.

======================================================================

The crop evapotranspiration, ET_c, was calculated by multiplying the reference crop evapotranspiration (ET_o) by a crop coefficient (K_c) according to [37]:

ETc = Kc * ETo…… mm / day

Where:

ET_c crop evapotranspiration [mm d^-1].

K_c crop coefficient [dimensionless].

ET_o reference crop evapotranspiration [mm d^-1].

The irrigation requirements (IR) for each treatment was calculated as follows:

IR = ETc * (LR) * 4.2 / Ea ...… (m3 / 4200 m2/ day)

Where:

LR % = Leaching requirement percentage.

Ea = the irrigation system's efficiency (The value in the subsurface irrigation system was 95%, the drip irrigation system 85% and the surface irrigation system 55%). Irrigation was carried out every 8 days in the drip irrigation and subsurface irrigation system, and 20 days in the case of Surface irrigation, according to the weather conditions in the study area.

*Yellow paragraphs added recently

====================================================================

A description of the surface irrigation system has not been presented. The content contained in this part concerns the description of all the experimental plots.

 Based on the recommendation, a description of the surface irrigation system was presented.

The surface irrigation system is done by distributing water through small Mesqa and smaller order ditches called Marwa (control treatment), it is the most common irrigation system in Egyptian agriculture.

My serious concern is the experiment scheme presented in Fig. 1. It shows that the experimental plots are very close to each other and therefore there is a very high probability that neighboring experiments will interact with each other. 

By browsing some references in this field, it was found that the distance of 3 meters is acceptable, especially in the lack of research resources

I was very surprised to receive the quotation from the literature on the calculations of evapotranspiration (lines 139, 140). Item [37] concerns "The state of food insecurity" 

Well, it has been corrected

FAO. Crop evapotranspiration - Guidelines for computing crop water requirements - FAO Irrigation and drainage paper 56. 1998.  https://www.fao.org/3/x0490e/x0490e00.htm

A similar situation occurs with the WUE (lines 171,172) where reference is made to "World review livestock production ..." [49]. 

Well, it has been corrected

FAO. Crop water requirements irrigation and drainage. Paper No. 24, Rome Italy. 1982 https://www.fao.org/publications/card/en/c/43024473-a2c0-515b-9bf2-0fa4d1dfbb19.

Taking into account that we use the SI system, in which 1 cm = 10 mm, it is interesting how the authors obtained such high accuracy of plant height measurements presented in many places in the work, including line 199.

Ten plants were taken from each experimental plot after 65 days from the date of planting to determine the of the plant height, a ruler was used to measure the height of the plant in cm unit and then the average of these plants was taken to prepare the data for statistical analysis, as mentioned previously in Materials and Methods.

The averaging of the leaf area value used by the authors makes sense, while specifying the average value of the number of leaves is not (lines 200, 202, others) 

It has been explained previously

In Figure 2 there is no description of the y axis (units and description), no "b" designation, and no "c" drawing / diagram at all.

Well, it has been corrected

I would like to mention: This figure is a display of the data in Table No. 6, which is the same data and was placed for further clarification only, and therefore it was discussed when discussing Table No. 6

Mark of sq meter in line 53 and sq cm in line 228

Well, it has been corrected

What is a "2.2 Experimental design" in line 113 ?

Well, it has been corrected

2.2 Experimental design

The treatments comprised three………..

Many thanks for the corrections and additions that have improved the manuscript.

Author Response File: Author Response.pdf

Reviewer 3 Report

Please find the review attached.

Comments for author File: Comments.pdf

Author Response

Review Report Form 2

Comments and Suggestions for Authors

Section 1. The introduction is chaotic and sloppy, and for the most part is about the plant, not the control of greenhouse gases - it does not link to the abstract.

It may seem that the manuscript not entirely related to the control of greenhouse gases, and mainly focuses on improving the yield and quality of the green bean crop, but the authors considered it important to link production processes (represented by the experimental parameters) with the control of greenhouse gas emissions, because through of the Intergovernmental Panel on Climate Change (IPCC) Reports, it is clear that most of the gas activities emitted from the agricultural sector result from the use of nitrogen fertilizers to plant nutrition (this was mentioned in the penultimate idea in the introduction) and to cover this excellent recommendation some research has already been added on the process of greenhouse gas emissions and its relationship to nitrogen fertilization.

 L 49-50: Repetition in the sentence: as reported by FAO [7]

Repetition in the sentence has been removed

 L 54: The sentence ends suddenly: …with a production of about 170 thousand tones in [10].

The sentence has been modified “The cultivated area reached about 41.5 thousand feddans (feddan = 4200 m2 and hectare = 2.4 feddans), with a production of about 170 thousand tones in 2020 [10]”

 L 5-58: The two sentences are not connected. The Authors don’t explain in later text what the information is for?

A paragraph has been added to explain the information

L 92: In agricultural science, the minimum number of seasons when field experiments are conducted in 3 years.

After searching in some references in this field, I found that in agricultural sciences, the minimum number of seasons in which field experiments are conducted in two agricultural seasons.

 L 99: Where do these data come from, how far from the plantation is the station? Why are weekly averages shown instead of 10-day or monthly averages?

The agricultural meteorological station is located inside the research farm in which the experiment was carried out, and it is about 5 km from the area of the experiment. The weekly averages were shown to facilitate the presentation.

Subsection 2.1 Experimental site, cultivar, and cultivation lacks the climatic characteristics (climate norm) of this area, which is a standard in this type of work

Experimental site: mentioned in Section 1 (2.1 Experimental site, cultivar and cultivation)

Cultivar: mentioned in Section 1 (2.1 Experimental site, cultivar and cultivation)

Climatic characteristics: mentioned in n Table 1

Which is a standard in this type of work: The standard in the irrigation system is flood irrigation (surface irrigation), mentioned in this paragraph (Flood irrigation as a control treatment)

 L 113 and 119: Number subsection 2.2 duplicates

Duplicates has been modified

 L 114: The experimental design section lacks information on the area of the field experiment, dimensions and area of plots and sub-plots

There is a paragraph to explain these details found after (2.3 Irrigation systems). To implement the recommendation, this paragraph has been moved to (2.2 Experimental design)

L116: Recommended dose of 85 N - is it kg/ha or kg/feddan - please specify the unit

Recommended dose of 85 N - is it kg/feddan

The unit has been added in the manuscript

 L 121: please develop the abbreviation: P.E.

P.E.: Polyethylene

The abbreviation has been added in the manuscript

 In the section Irrigation systems, the Authors did not mention important information regarding irrigation. The question regards drip and subsurface irrigation:

- how long were the drip lines?

- how far was the distance between lines?

- were the lines placed in each row, or every second one?

- what was the pressure in the system?

- where did the water come from? A well, municipal water system, pond, or river?

- how the water was transported?

- how the soil moisture was monitored?

- what was the schedule of irrigation?

- how many doses, how much water per irrigation dose, how frequent?

This was explained in the manuscript in more than one paragraph

This was explained in the manuscript in many paragraphs, for example:

=====================================================================

2.3 Irrigation systems

2.3.1 Drip irrigation

Manifold lines were 32 mm diameter, polyethylene (P.E.) pipe used to supply laterals (drip lines) with the irrigation water. Drip tubing (type GR, 16mm diameter), with in-built emitters at 0.3m cm spacing, was used (delivering of 4 L per hour), the long of the drip line was 30 meters, one drip line was placed on each rows, 2 Bar pressure was maintained at drip tubing, the water source used was a river, and the water was transferred by the control station of the farm. The experi-mental plot had a flowmeter as shown in the Figure, 1.

======================================================================

The crop evapotranspiration, ET_c, was calculated by multiplying the reference crop evapotranspiration (ET_o) by a crop coefficient (K_c) according to [37]:

ETc = Kc * ETo…… mm / day

Where:

ET_c crop evapotranspiration [mm d^-1].

K_c crop coefficient [dimensionless].

ET_o reference crop evapotranspiration [mm d^-1].

The irrigation requirements (IR) for each treatment was calculated as follows:

IR = ETc * (LR) * 4.2 / Ea ...… (m3 / 4200 m2/ day)

Where:

LR % = Leaching requirement percentage.

Ea = the irrigation system's efficiency (The value in the subsurface irrigation system was 95%, the drip irrigation system 85% and the surface irrigation system 55%). Irrigation was carried out every 8 days in the drip irrigation and subsurface irrigation system, and 20 days in the case of Surface irrigation, according to the weather conditions in the study area.

*Yellow paragraphs added recently

====================================================================

L 147: The unit of the area should be presented in SI system or other universal worldwide e.g. hectare

The unit has been changed from m³ fed-1 to m³/ 4200 m²

L 150: transplanting date - what do the Authors mean by this expression?

Has been changed from transplanting date to planting date

L 173: the unit of WUE is expressed typically in kg ha − 1 mm – 1

According to the references in the paragraph, it is expressed as kg/m3

195-293: The results are described in a not very concise manner. The graphic forms would assist well in the analysis.

Because the experience is factorial, and each factor is described separately, then the interaction between treatment.

L 117: Section of Discussion - this section is a continuation of the research results section and I propose to combine both chapters into one and titled Results and Discussion.

Thanks for the suggestion, but this is difficult now, it will be done in the next manuscripts

L 160-162: I don’t understand these sentences. Their meanings are opposite.

If you mean 160-162, the sentences have been revised

L 308: Reference no 37 - This DOI cannot be found in the DOI System.

Has been changed

At this stage of preparation, the manuscript requires correction by the Authors. I also suggest proofreading the manuscript before the resubmission.

Many thanks for the corrections and additions that have improved the manuscript. Correction done by the authors. The manuscript was also checked before being resubmitted.

Author Response File: Author Response.pdf

Reviewer 4 Report

The manuscript entitled “Control of Gas Emissions (N2O and CO2) Associated with Ap-2 plied Different rates of Nitrogen and their influences on 3 Growth, Productivity and Physio-biochemical Attributes of 4 Green Bean Plants Grown under Different Irrigation Methods” is submitted to Agronomy. The study includes valuable information about N management and irrigation systems. The manuscript has been written very well, I have provided some points that I hope they are helpful for authors to improve their work.

Abstract, ”N fertilization as 60, 70, 80, 90, 100, 110 and 120 of” Please add “%” before “of”.

The big question in this study is the difference of amount of water between different irrigation systems. In fact, there are two source of difference, irrigation system and amount of water. How can we distinguish the difference of yield in different irrigation system is just because of type of irrigation or amount of water.

Please add more detail about preparation of soil before planting.

Did you inoculate the seeds before planting?

The unit of yield should be ton/ha.

There were no significant effect of irrigation system in gas emission?

Line 119, change “(24, 52)” to “[24, 52]”

Author Response

Review Report Form 3

Comments and Suggestions for Authors

Abstract, ”N fertilization as 60, 70, 80, 90, 100, 110 and 120 of” Please add “%” before “of”.

'%' has been added before 'from'.

The big question in this study is the difference of amount of water between different irrigation systems. In fact, there are two source of difference, irrigation system and amount of water. How can we distinguish the difference of yield in different irrigation system is just because of type of irrigation or amount of water.

Indeed, there was a difference in the amount of water between the different irrigation systems, but basically the difference in the amount of water is due to the different irrigation systems, and thus the effect is reflected on the irrigation systems

Please add more detail about preparation of soil before planting.

More details about soil preparation before planting have been added in Materials and Methods

Did you inoculate the seeds before planting?

All agricultural practices were carried out in accordance with the recommendations of the Egyptian Ministry of Agriculture, and only changes were made in the methods of irrigation and nitrogen fertilization

The unit of yield should be ton/ha.

A local unit of measurement for cultivated areas in Egypt, Hectare = 2.4 feddan.

There were no significant effect of irrigation system in gas emission?

Yes

Line 119, change “(24, 52)” to “[24, 52]

Done

Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

The Authors did not supplement the information about climate background, which I asked. Also, not incorporated the section regarded nitrogen fertigation and GHGs emission into Results section. 

Author Response

Review Report Form 3

 (Round 2)

Comments and Suggestions for Authors

The Authors did not supplement the information about climate background, which I asked. Also,

The Egyptian Ministry of Agriculture owns the Agricultural Research Center, which owns the Central Laboratory for Agricultural Climate. One of the most important tasks of this central laboratory is to cover all cultivated areas in Egypt with agricultural weather stations. The lab collects this data and puts it in a database available to researchers and agricultural scientific research. The meteorological data for the experiment for the study area were obtained from one of the agricultural meteorological stations located in this area.

Not incorporated the section regarded nitrogen fertigation and GHGs emission into Results section. 

This section is already covered in the results

3.5 Greenhouse Gas Emission from Nitrogen Fertilization

The balanced greenhouse gas (GHG) emissions differed according to the different applied nitrogen fertilisation amounts (Table 7)………. (line 102:112)

Author Response File: Author Response.pdf

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.