Response of Multi-Stressed Olea europaea Trees to the Adjustment of Soil pH by Acidifying Agents: Impacts on Nutrient Uptake and Productivity

Round 1

Reviewer 1 Report

Point 1:

Introduction

…. Chemically, soil pH can be defined as the negative logarithm of 34

the active hydrogen (H+) or hydroxyl (OH-) ion concentration, in short, pH-35 log [H+] or – log [OH−] [3,4].

Comment:

In [3], acidity and alkalinity were defined in the introduction as: “Soil pH is a measurement for acidity and alkalinity of the soil solution. It can be defined as the negative logarithm of hydrogen ion concentration [H+] or hydroxide ion concentration [OH-], or simply, pH = -log [H+]; pH= -log [OH-] . “

There is an error: “ pH = -log[OH^-]”  it would say “pOH = -log[OH^-]”

Suggestion: Please, rewrite the sentence.

Point 2:

… as well as materials containing ammonium (NH+) 81

It sould say (NH₄⁺)

Point 3:

3.2. Leaf macro and micronutrient content

The results shown in Tables 5…

It should say ‘Table 6’

Pont 4:

Table 5 should be revised.

SE is missing

I recommed one-way ANOVA with repeated measures to assess the main effect of time,  the main effect of treatment, and interactions.

Point 5:

It can be seen from Table 6 that the increasing percentages of the highest and lowest values were 133.34 vs. 126.53 for LFeC, 50.31 vs. 23.46 for LMnC, 38.56 vs. 46.04 for LZnC and 215.11 vs. 138.29 for LCuC in the 2018 and 2019 seasons, respectively.

It should say ‘Table 7’

Point 6:

The data pertaining to the impact of the applied acidifying agents, irre-spective of doses, indicated that CA generally surpassed the other acids, as shown in Figures (1-3).

It should say ‘Figure 1’. And in figure 1, the letter ‘A’, ‘B’,’C’  would be added.

The results (Figures 4-6) showed that all applied acids markedly increased the studied physiological parameters, including SPAD chlorophyll, Fv/Fm and performance index (PI).

It should say ‘Figure 2’.

Point 7:

3.4. The heat map of correlation coefficient. 22

The results of the correlation analysis between leaf nutrient contents (N, P, K, Ca, Mg 23 and Na), physiological and growth parameters (ShL, NLf, LA and SPAD reading), and 24 yield and its attributes (TFrW, FrL, FrW, FrDrM, FiW and TOY) is shown in Figure 9.

It should say ‘…are shown in Figure 3’  (the letters ‘A’, ‘B’ should be added to the graphics, and in the title of the figure the season for each letter.

Point 8:

2.4. Soil sampling and determination of chemical and physical properties

extracted with 1N NH4AC

It should say ‘extracted with ammonium acetate (1M NH₄CH₃CO₂)’.

Point 9:

       Fur-32

thermore, the nature of the parent material, and predominance of basic cations, such as 33

 Ca++, Mg++ and Na+, and their accumulation also have an effect on soil pH. In addition, 34

were measured via the EDTA titration method. Soluble anions, such as HCO3⁻, CO3⁻⁻ and Cl⁻, were determined via the titration method described by [42]. SO4^—ions were calculated as the difference between total soluble cations and anions.

It should say ‘ Ca²⁺ , Mg²⁺  ‘ ;  ‘CO3²⁻  ’  ; ‘SO4^2- ‘

Point 10:

These 44

 findings could be attributed to the potentially quick disappearance of AC, owing to its 45

loss by volatilization [53].

I don’t agree. I think the reference [53] is about organic compounds in general, but you may have revised the chemical properties of acetic acid, citric acid, and sulfuric acid to explain this sentence.

It may be that, when the wet soil is maintained under field conditions, reduced conditions could develope, and then the increase in pH would be observed.

Point 11:

This slight decrease could be 47

 attributed to the decomposition of H2O molecules into OH⁻ and H⁺ ions in soil and the 48

 subsequent adsorption of H+ ions on soil particles as a result of ion substitution between 49

 H⁺ and other base ions, such as Ca⁺⁺, Mg⁺⁺ and Na⁺.

I don’t agree. A decrease in pH means an increase in the concentration of H⁺ in soil solution. This effect is related to the potential acidity of soils, which occurred when salts, such as KCl, were added to the soil solution.

Point 12:

AA1>AA2>CA2>CA1>SA1>SA2. The effect of the application of both AA and CA   52

‘AA’ will say ‘AC’

Point 13:

[Eq. 2.] H2SO4 + 2CaCO3     à    Ca²⁺ + SO4²⁻ + 2HCO3⁻                 71

The estequiometric coeficient of Ca is missing.   It must be ‘ 2 Ca²⁺’

Point 14:

to the considerable amounts of carbonate (HCO3⁻) ions formed 73

It should say ‘hydrogen carbonate’.

Point 15:

The references should be reviewed. Some should not be underlined. [45] , [46]. Some should be rewritten [67]

Author Response

Agronomy - MDPI

Manuscript ID: Agronomy-2168345

Manuscript Title:  "Response of Multi-stressed Olea europaea Trees to the Adjustment of Soil pH by Acidifying Agents: Impacts on Nutrients Uptake and Productivity"

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

Dear Reviewer NO 1.

         Thank you for your efforts and I’d like also to thank you very much for their valuable comments. Where I am very happy that our manuscript was satisfied with you, and I have the great honor to publish in your valuable journal. We have corrected the manuscript based on your valuable comments, and the corrections made in the text in red color, and are outlined step by step as follows:

Review Report Form

Comments and Suggestions for Authors

Point 1:

……… chemically, soil pH can be defined as the negative logarithm of [34] the active hydrogen (H+) or hydroxy (OH−) ion concentration, in short, pH-35 log [H+] or – log [OH] [3,4]

In [3], acidity and alkalinity were defined in the introduction as: “Soil pH is a measurement for acidity and alkalinity of the soil solution. It can be defined as the negative logarithm of hydrogen ion concentration [H⁺] or hydroxide ion concentration [OH^-], or simply, pH = - log [H⁺]; pH= - log [OH^−]. There is an error: “pH = - log[OH^-]”  it would say “pOH = - log[OH^−]. Suggestion: Please, rewrite the sentence.

Rep: done (lines 36-38)

Point 2:

……… as well as materials containing ammonium (NH⁺) 81. It should say (NH₄).

Rep: done (line 84)

Point 3:

3.2. Leaf macro and micronutrient. The results shown in Tables 5 …… It should be say Table 6.

Rep: done (line 235)

Point 4:

Table 5 should be revised

I recommend one-way ANOVA with repeated measures to assess the main effect of time, the main effect of treatment, and interactions.

Rep: the SE value was written.

Point 5:

It can be seen from Table 6 that the increasing percentages of the highest and lowest values were 133.34 vs. 126.53 for LFeC, 50.31 vs. 23.46 for LMnC, 38.56 vs. 46.04 for LZnC and 215.11 vs. 138.29 for LCuC in the 2018 and 2019 seasons, respectively. It should say Table 7.

Rep: done (line 291).

Point 6:

The data pertaining to the impact of the applied acidifying agents, irrespective of doses, indicated that CA generally surpassed the other acids, as shown in Figures (1-3). It should say ‘Figure 1’. And in figure 1, the letter ‘A’, ‘B’,’C’  would be added.

Rep: done (lines 298 and 299).

The results (Figures 4-6) showed that all applied acids markedly increased the studied physiological parameters, including SPAD chlorophyll, Fv/Fm and performance index (PI). It should say Figure 2.

Rep: done (line 314).

Point 7:

3. 4. The heat map of correlation coefficient 22.

The results of the correlation analysis between leaf nutrient contents (N, P, K, Ca, Mg 23 and Na), physiological and growth parameters (ShL, NLf, LA and SPAD reading), and 24 yield and its attributes (TFrW, FrL, FrW, FrDrM, FiW and TOY) is shown in Figure 9. It should say ‘…are shown in Figure 3’ (the letters ‘A’, ‘B’ should be added to the graphics, and in the title of the figure the season for each letter.

Rep: done (lines 367 and 368) and added in the title of graphics.

Point 8:

2.4. Soil sampling and determination of chemical and physical properties extracted with 1N NH4AC. It should say ‘extracted with ammonium acetate (1M NH₄CH3CO2)

Rep: done (line 172).

Point 9:

Furthermore, the nature of the parent material, and predominance of basic cations, such as 33. Ca⁺⁺, Mg⁺⁺ and Na⁺, and their accumulation also have an effect on soil pH. In addition, 34. were measured via the EDTA titration method. Soluble anions, such as HCO₃^−, CO₃^—and Cl^−, , were determined via the titration method described by [42]. SO₄^—ions were calculated as the difference between total soluble cations and anions. It should say ‘ Ca²⁺ , Mg²⁺  ‘ ;  ‘CO3^2−  â€™  ; ‘ SO₄^−2.

Rep: done (in materials and methods section; lines 171 and 173-175) and (in discussion section; lines 377, 394, 420 and 477) and

Point 10:

findings could be attributed to the potentially quick disappearance of AC, owing to its 45 loss by the volatilization [53].

I don’t agree. I think the reference [53] is about organic compounds in general, but you may have revised the chemical properties of acetic acid, citric acid, and sulfuric acid to explain this sentence. It may be that, when the wet soil is maintained under field conditions, reduced conditions could develope, and then the increase in pH would be observed.

Rep: yes, as the acetic and citric acids are considered organic compounds

Point 11:

This slight decrease could be 47 attributed to the decomposition of H2O molecules into OH^− and H⁺ ions in soil and the 48. subsequent adsorption of H+ ions on soil particles as a result of ion substitution between 49  H⁺ and other base ions, such as Ca⁺⁺, Mg⁺⁺ and Na+. I don’t agree. A decrease in pH means an increase in the concentration of H⁺ in soil solution. This effect is related to the potential acidity of soils, which occurred when salts, such as KCl, were added to the soil solution.

Rep: done

Point 12:

AA₁>AA₂>CA₂>CA₁>SA₁>SA₂. The effect of the application of both AA and CA 52. ‘AA’ will say ‘AC”

Rep: done (line 397).

Point 13:

[Eq. 2.] H₂SO₄ + 2CaCO₃     Ã     Ca²⁺ + SO₄^2− + 2HCO₃^−

The estequiometric coefficient of Ca is missing.   It must be‘ 2 Ca

Rep: done (line 417).

Point 14:

to the considerable amounts of carbonate (HCO₃^−) ions formed 73. It should say ‘hydrogen carbonate.

Rep: done (line 419).

Point 15:

The references should be reviewed. Some should not be underlined. [45] , [46]. Some should be rewritten [67].

Rep: done.

  Many thanks to Reviewer 1 for his valuable comments

Ahmed A. M. Awad (Corresponding author)

January21, 2022 

Author Response File: Author Response.pdf

Reviewer 2 Report

The revised manuscript entitled  "Response of Multi-stressed Olea europaea Trees to the Adjustment of Soil pH by acidifying agents: Impacts on Nutrient Uptake and Productivity" is interesting and easy to read. However, before the final publication, some corrections are required, especially in the Material and Methods and Conclusion sections. All my comments are marked in a manuscript text.

Comments for author File: Comments.pdf

Author Response

Agronomy - MDPI

Manuscript ID: Agronomy-2168345

Manuscript Title:  "Response of Multi-stressed Olea europaea Trees to the Adjustment of Soil pH by Acidifying Agents: Impacts on Nutrients Uptake and Productivity"

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

Dear Reviewer NO 2.

         Thank you for your efforts and I’d like also to thank you very much for their valuable comments. Where I am very happy that our manuscript was satisfied with you, and I have the great honor to publish in your valuable journal. We have corrected the manuscript based on your valuable comments, and the corrections made in the text in red color, and are outlined step by step as follows:

Review Report Form

Comments and Suggestions for Authors

The revised manuscript entitled “Response of Multi-stressed Olea europaea Trees to the Adjustment of Soil pH by Acidifying Agents: Impacts on Nutrient Uptake and Productivity”.is interesting and ease to read. However, before the final publication, some corrections are required, especially in the materials and methods and conclusion sections. All my comments are marked in a manuscript text.

Introduction

Point 1: (lines 34-38). Chemically, soil pH …………………..at 7 are considered neutral [5].

Re: done (lines 36-38)

Point 2: (lines 46-49). Brady and Weil, 2010 …………….. to an increase in soil pH.

Re: done as shown in red color (lines 49-51).

Point 3: in line 68

Re: done (lines 71 and 72).

Materials and Methods

Point 4: (line 116-119). Two field experiments …………………… with an optimal range.

Re: done (lines 121-125).

Point 5: (lines 131-136). The fertilization program included ………………………. And 400 g per tree, respectively.

Re: done (lines 141-146).

Point 6:

Re: all corrections were done (line 148-162)

Point 7: as shown in Table 3.

Re: it remain the same after deleting the previous table (line 173).

Point 8: ECe

Re: done (line 174-175)

Point 9: Table … (line 218)

Re: done

Point 10: In table 7. Flesh weigh; flesh weight/total fruit weight and flesh dry matter.

Re: we carefully reviewed. All abbreviations are correct.

Point 11: The reaction ….. with soil nutrients [60].

Re: done

Point 12: As a result of the positive ……………………. And its attributes.

Re:  done (line 485-496)

Point 12: In conclusion

Re: done

Many thanks to Reviewer 2 for his valuable comments

Ahmed A. M. Awad (Corresponding author)

January 22, 2022 

Author Response File: Author Response.pdf

Reviewer 3 Report

Dear authors,

Thank you for the opportunity to review this Manuscript (Response of Multi-stressed Olea europaea Trees to the Adjustment of Soil pH by acidifying agents: Impacts on Nutrient Uptake and Productivity). The study used acidifying agents (acetic acid, citric acid, and sulfuric acid) to lower soil pH and evaluated their potential impacts on nutrient availability, which in turn influences physiological and growth parameters, the yield of table and oil olives, and the fruit’s physical attributes. There is some aspect that should be reviewed by authors, but the study is well written and brings important results.

PLEASE, THE EDITIONS SHOULD BE ADDED TO THE MANUSCRIPT AND ANSWERED IN THE LETTER

The title is good.

The abstract is clear and brings all information required.

keywords: There are words similar in the title. Please, check it.

The introduction is good. However, I recommend some editions

 Lines 46-47: check the references

In a Future study, the authors could test the use of fertilizer (i.e., urea)  that increases the pH of soil.

Lines  15-98. It is objective, there is no need to add it here

Material and Methods

In general, The Figures and Tables have a low quality

Soil characterization (chemical and physical) should be presented as a better-quality table (data in Table 4). In addition, this table should be presented in the first topic in the Material and Methods  

Soil classification

Table 1, should be presented as a Figure

There is no need for Tables 2 and 3. Please, add this information to the text

Table 5, should be presented as a Figure. It is not clear to understand as a table.

The figures also have low quality        

The interpretation of results is not correct. The authors have a double factorial. Therefore, the results can be explained by rates and sources. All Figures and Tables should be analyzed. Questions are not explained: “Which is the best rate/source?”

Author Response

Agronomy - MDPI

Manuscript ID: Agronomy-2168345

Manuscript Title:  "Response of Multi-stressed Olea europaea Trees to the Adjustment of Soil pH by Acidifying Agents: Impacts on Nutrients Uptake and Productivity"

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

Dear Reviewer NO 3.

         Thank you for your efforts and I’d like also to thank you very much for their valuable comments. Where I am very happy that our manuscript was satisfied with you, and I have the great honor to publish in your valuable journal. We have corrected the manuscript based on your valuable comments, and the corrections made in the text in red color, and are outlined step by step as follows:

Review Report Form

Comments and Suggestions for Authors

Dear author. Thank you for the opportunity to review this Manuscript (Response of Multi-stressed Olea europaea Trees to the Adjustment of Soil pH by acidifying agents: Impacts on Nutrient Uptake and Productivity). The study used acidifying agents (acetic acid, citric acid, and sulfuric acid) to lower soil pH and evaluated their potential impacts on nutrient availability, which in turn influences physiological and growth parameters, the yield of table and oil olives, and the fruit’s physical attributes. There is some aspect that should be reviewed by authors, but the study is well written and brings important results.

PLEASE, THE EDITIONS SHOULD BE ADDED TO THE MANUSCRIPT AND ANSWERED IN THE LETTER.

The title is good.

The abstract is clear and bring all information required.

Keywords: There are words similar in the title. Please, check it.

Re: Done, the word “ soil pH” was changed to “soil reaction”

The introduction is good. However, I recommended some editions

Lines 46-47. Check the references.

Re: done

In a Future study, the authors could test the use of fertilizer (i.e., urea)  that increases the pH soil.

Re: Thank you so much for this attention, usually, we do not tend to use urea, as it is a fertilizer with an alkaline effect that does not suit the nature of Egyptian soils with a high pH. However, it is possible to test the effect of modifying agents on lowering the soil pH caused by the use of the alkaline fertilizers such as urea. 

Lines  15-98. It is objective, there is no need to add it here.

Materials and Methods

In general, The Figures and Tables have a low   

Soil characterization (chemical and physical) should be presented as a better-quality table (data in Table 4). In addition, this table should be presented in the first topic in the Material and methods

Re: done

Soil classification

Table 1, should be presented as a figure

Re: we tried to present the data in Table 4 in the form of a graphic. But it was very crowded.

There is no need for Tables 2 and 3. Please, add this information to the text.

Re: I have merged the two tables (2 and 3) into one (Table 2).

 Table 5, should be presented as a Figure. It is not clear to understand as a table

Re: we tried to present the data in Table 4 in the form of a graphic. But it was very crowded.

The figures also have low quality.

Re: modified

The interpretation of results is not correct. The authors have a double factorial. Therefore, the results can be explained by rates and sources. All Figures and Tables should be analyzed. Questions are not explained: “Which is the best rate/source.?

Re: I did not understand this point (Please clarify)

  Many thanks to Reviewer 2 for his valuable comments

Ahmed A. M. Awad (Corresponding author)

January 22, 2022 

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

The manuscript was improved according to all reviewer's comments. I recommend publishing the manuscript.

Author Response

Have corrected

Thanks

Reviewer 3 Report

This version of the manuscript can be published. However, the authors should use the agronomy template.

Author Response

Have corrected

Thanks