Balanced Fertilization with Nitrogen, Molybdenum, and Zinc: Key to Optimizing Pecan Tree Yield and Quality of Western Schley Pecan Tree

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This study investigates the effects of balanced fertilization with N, Mo, and Zn on the growth and productivity of pecan trees. Using a Taguchi L16 experimental design, the research evaluates various combinations of these fertilizers on leaf nutrient content, photosynthesis, enzyme activity, and yield. Results show significant improvements in nitrate reductase activity, chlorophyll content, and productivity with optimal fertilization. The study highlights the importance of integrated fertilization for enhancing tree health and yield, particularly in mitigating zinc deficiency, and suggests further research on long-term effects and practical applications in different environments. I have the following the question and comments for this manuscript.

 

1. Abstract: The general description in the abstract is insufficient. It would be more impactful to include specific data, such as numerical results, to highlight key findings. For example, including percentages of improvement in nitrate reductase activity, chlorophyll content, or productivity would provide a clearer picture of the study's outcomes.
2. Introduction: The research gap and significance should be described in more detail. The objectives need to be more concise and directly aligned with the study's hypotheses. Additionally, some references are cited redundantly (e.g., [3] and [5,6]), which could be streamlined for clarity.
3. Line 74: The soil nutrient data should be reported in units of mg/kg or g/kg. Furthermore, the methods used to test soil nutrients should be clearly listed to ensure transparency and reproducibility of the results.
4. Growth Stage & Sampling Timing: The manuscript does not specify at which specific growth stages measurements such as chlorophyll content and enzyme activity are taken. Timing is crucial as physiological responses can vary across the growing season, and this information is necessary for interpreting the results accurately.
5. Initial Soil Nutrient Status: The initial soil nutrient levels, such as available N, Zn, and Mo, should be measured before applying treatments. This baseline data would help in interpreting the effects of fertilization and ensure that observed changes are due to the treatments rather than pre-existing nutrient levels.
6. Data Analysis: The data analysis section is a bit vague. While statistical methods are mentioned, specific numerical results (such as values for enzyme activity, nutrient concentrations) and the corresponding statistical outputs (e.g., p-values, F-statistics) should be presented clearly. This would improve the transparency of the analysis and help assess the statistical significance of the findings.
7. Line 239: The sentence in line 239 needs revision for clarity and coherence. Please ensure it communicates the intended message in a more straightforward manner.
8. Tables 4-7: Tables 4-7 are somewhat difficult to understand. Consider revising them or providing more detailed explanations in the text to clarify the data presented.
9. Figures 1a-1d: Figures such as 1a-1d should include statistical values like p-values and R² values. These values will help interpret the strength of the relationships being shown in the figures and provide a clearer understanding of the results.
10. Discussion: While the biological mechanisms behind the observed improvements in photosynthesis and enzyme activity are discussed, the manuscript could further explore why these improvements are particularly significant for pecan trees, especially in the context of environmental stressors such as drought. A more detailed explanation of how the fertilizers mitigate these stressors would provide valuable insight into the practical application of the findings.
11. Optimal rates of Fertilizers: The manuscript does not discuss the threshold levels for each fertilizer (e.g., the optimal nitrogen level for pecans) in depth. It would be beneficial to include insights on how varying amounts of nitrogen, molybdenum, and zinc influence different growth stages and long-term yields in pecan trees. This would provide a more comprehensive understanding of how to optimize fertilization practices for improved growth and productivity.

 

Author Response

Comments 1: Abstract: The general description in the abstract is insufficient. It would be more impactful to include specific data, such as numerical results, to highlight key findings. For example, including percentages of improvement in nitrate reductase activity, chlorophyll content, or productivity would provide a clearer picture of the study's outcomes.

Response 1: We appreciate this observation, we included specific data and improved the abstract.

 

Comments 2: Introduction: The research gap and significance should be described in more detail. The objectives need to be more concise and directly aligned with the study's hypotheses. Additionally, some references are cited redundantly (e.g., [3] and [5,6]), which could be streamlined for clarity.

Response 2: Thank you comment, in response, we have revised the txt from lines 27 to 63 to improve the clarity and coherence of the writing. Redundant references have been eliminated, and emphasized to strengthen the scientific farmer work of the study

 

Comments 3: Line 74: The soil nutrient data should be reported in units of mg/kg or g/kg. Furthermore, the methods used to test soil nutrients should be clearly listed to ensure transparency and reproducibility of the results.

Response 3: We have standardized the units of the soil nutrient data to mg kg-1, as recommended. Furthermore, the analytical methods used for soil nutrient determination are now clearly described in the study area and location section (lines 73 a 84).

 

Comment 4: Growth Stage & Sampling Timing: The manuscript does not specify at which specific growth stages measurements such as chlorophyll content and enzyme activity are taken. Timing is crucial as physiological responses can vary across the growing season, and this information is necessary for interpreting the results accurately.

Response 4: the specific growth stage at which chlorophyll content and enzyme activity were measured has been added to manuscript. (lines 108, 141, 169,193 y 216)

 

Comment 5: Initial Soil Nutrient Status: The initial soil nutrient levels, such as available N, Zn, and Mo, should be measured before applying treatments. This baseline data would help in interpreting the effects of fertilization and ensure that observed changes are due to the treatments rather than pre-existing nutrient levels.

Reponses 5: Thank you for your observation. A preliminary soil analysis was conducted before treatment application; however, molybdenum (Mo) was not included in the initial panel, as its relevance became evident only after treatment effects were observed. This limitation has been acknowledged in the revised version of the manuscript (lines 73-84).

 

Comment 6: Data Analysis: The data analysis section is a bit vague. While statistical methods are mentioned, specific numerical results (such as values for enzyme activity, nutrient concentrations) and the corresponding statistical outputs (e.g., p-values, F-statistics) should be presented clearly. This would improve the transparency of the analysis and help assess the statistical significance of the findings.

Response 6: We clarify that statistical values such as means and R2 are reported in the main tables. Additionally, new tables have been included with the corresponding probability values (p-values) and significance levels to enhance the transparency and interpretation of the results (see tables 5,7 and 9)

 

Comment 7: Line 239: The sentence in line 239 needs revision for clarity and coherence. Please ensure it communicates the intended message in a more straightforward manner.

Response 7: The wording of the paragraph corresponding to line 239 has been revised to improve clarity and coherence, ensuring a more direct communication of the original message

 

 

Comment 8: Tables 4-7: Tables 4-7 are somewhat difficult to understand. Consider revising them or providing more detailed explanations in the text to clarify the data presented.

Response 8: The discussion of the results and the references to Tables 4-7 have been revised to ensure they are presented more clearly ad comprehensibly. We hope that the update explanations in the text now facilitate better understanding of the data.

 

Comment 9: Figures 1a-1d: Figures such as 1a-1d should include statistical values like p-values and R² values. These values will help interpret the strength of the relationships being shown in the figures and provide a clearer understanding of the results.

Response 9: Thank you for your valuable suggestion. In response, we confirm that the R2 values for each variable are reported in the corresponding tables of the manuscript. Additionally the figures including the repones surface plot.

 

Comment 10: Discussion: While the biological mechanisms behind the observed improvements in photosynthesis and enzyme activity are discussed, the manuscript could further explore why these improvements are particularly significant for pecan trees, especially in the context of environmental stressors such as drought. A more detailed explanation of how the fertilizers mitigate these stressors would provide valuable insight into the practical application of the findings.

Response 10: Thank your insightful comment. The discussion section has been expanded to address the significance of the observed physiological improvements in pecan tree (lines 544-552)

 

Comment 11: Optimal rates of Fertilizers: The manuscript does not discuss the threshold levels for each fertilizer (e.g., the optimal nitrogen level for pecans) in depth. It would be beneficial to include insights on how varying amounts of nitrogen, molybdenum, and zinc influence different growth stages and long-term yields in pecan trees. This would provide a more comprehensive understanding of how to optimize fertilization practices for improved growth and productivity.

Response 11: We have added a discussion on the optimal response levels for -n, Mo and Zn in lines 529-533

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

-The abstract must be improved by more results and values

-What is your aim or goal in using spray application ?

-What is the initial concentration of Mo in soil?

-Drying samples at 70° can affect some volatile nutrients, such as nitrite and nitrate, which makes the real concentration of those nutrients incorrect

-L120, specifies the nature of leaf material used (dry, fresh,...)

-Check the protocols used; some of them need references 

-statistics section, too long, make it short if applicable 

-Check, L239, there is a mistake somewhere 

-the same for L447, what is ''int eh'' 

- The tables are not presented clearly

- Move the references and discussion used in the results section to the discussion section 

-Improve the results section by focusing more on differences between the control and the treatments, showing more values than correlations ( variables, factors ....)

-What are your recommendations about the dose, the time, and how your study can improve fruit quality

Author Response

Comment 1: The abstract must be improved by more results and values

Response 1: The abstract has been revised to include more specific results and numerical values.

 

Comment 2: What is your aim or goal in using spray application?

Response 2: This rationale has now been included in the introduction section to clarify its relevance.

 

Comment 3: What is the initial concentration of Mo in soil?

Response 3: Thank you for question. A preliminary is analysis was conducted prior to the experiment, however, Mo was not included in that initial panel, and its absence was no noticed until after the application had already begun. However, it is believed that since this micronutrient has low availability, not knowing its concentration does not significantly affect the results.

 

Comment 4: Drying samples at 70° can affect some volatile nutrients, such as nitrite and nitrate, which makes the real concentration of those nutrients incorrect

Response 4: Thank you for your comment. Upon reviewing the methodology, we identified a wording error. (see line 115)

 

Comment 5: L120, specifies the nature of leaf material used (dry, fresh,...)

Response 5: The nature of the leaf material used has been specified and added in line 143 of the revised manuscript.

 

Comment 6: Check the protocols used; some of them need references 

Response 6: The protocols have been reviewed, and the corresponding references have been added in the revised version of the manuscript

 

Comment 7: Statistics section, too long, make it short if applicable 

Response 7: The statical analysis section has been rewritten to make it more concise and focused. The revised version, located in lines 219 to 246, summarizes the essential methods while maintain clarity and scientific accuracy

 

Comment 8: Check, L239, there is a mistake somewhere 

Response 8: That part of the result section has been rewritten to correct the error and improve clarity.

 

Comment 9: the same for L447, what is ''int eh'' 

Response 9: Thank you for pointing that out. The typographical error has been corrected in the revised version of the manuscript

 

 

Comment 10: The tables are not presented clearly

Response 10: The tables have been revised to improve clarity and readability. We have also adjusted the way result is explained in the text to make them easier to understand and better aligned with the updated tables.

 

Comment 11: Move the references and discussion used in the results section to the discussion section 

Response 11: All references and interpretative discussions that were previously included int the results section have been moved to the discussion section, in accordance with standard scientific structure.

 

Comment 12: Improve the results section by focusing more on differences between the control and the treatments, showing more values than correlations ( variables, factors ....)

Response 12: The results section has been improved by adding more specific values to highlight the differences between the control and the treatments. However, the variables presents were selected based on the result of the multikey regression and canonical response surface analysis, in order to focus on the most statically significant and biologically relevant effects.

 

 

Comment 13: What are your recommendations about the dose, the time, and how your study can improve fruit quality

Response 13: Recommendations regarding optimal dose, timing of application and their potential impact have been added in the results sections, specifically in lines 460 to 472 of the revised manuscript

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

1. Line 62–64 (Introduction)
   The study objective is too general and lacks a clearly formulated hypothesis. It is recommended to explicitly state the research question and provide a testable hypothesis, such as: "We hypothesize that combined N–Mo–Zn fertilization will significantly improve physiological parameters and yield."
2. Lines 78–83 (Experimental Design)
   The use of a Taguchi L16 design is not sufficiently justified. Why was this method chosen over a full factorial or randomized block design? This is important, especially given that Taguchi designs typically assume additive effects, yet the authors report interactions.
3. Line 81
   The statement "77% applied to the soil and 33% as foliar fertilization" is mathematically incorrect. The sum exceeds 100%. Please clarify whether this refers to the number of applications or the proportion of total nutrient mass.
4. Tables 1 and 2
   The reported fertilizer levels are given both as molar concentrations and as kg/ha, but no clear conversion or explanation is provided. This makes it difficult to assess the agronomic relevance. A table linking solution concentrations to field application rates would be helpful.
5. Line 117 (Nitrate Determination)
   The method for NO₃ determination is described briefly but lacks detail about calibration standards, validation procedure, and accuracy. Since nitrate is a central variable, the analytical protocol must be more rigorous and reproducible.
6. Lines 238 onward (Section 3.1 – Foliar Nutrition)
   The interpretation relies heavily on eigenvalue thresholds, but there is no classical statistical analysis such as mean comparisons, ANOVA, or standard deviations. This reduces the transparency and reliability of the results.
7. Tables 4 and 5
   The tables contain key numeric data, but units are missing in some cases, and statistical significance is indicated only vaguely (e.g., * or **). Please provide full units, clarify significance levels, and present actual p-values where possible.
8. Figures 1–4 (Response Curves)
   While trends are shown graphically, the absence of error bars, R² values, and significance markers weakens the conclusions. Add statistical annotations to confirm model fit and biological relevance of the response surfaces.
9. Lines 317–349 (Enzymatic Activity)
   Although changes in enzyme activities (NR, urease) are reported, the physiological and agronomic significance of these findings is not adequately discussed. Please connect the enzyme data to real-world outcomes, such as nitrogen uptake or growth.
10. Lines 393–396 (Zinc Deficiency)
    The statement that N and Mo increase Zn deficiency contradicts earlier claims of nutritional improvement. This logical inconsistency needs to be addressed. Is the deficiency real or a relative effect based on plant uptake ratios?
11. Table 6 (Yield Parameters)
    No absolute yield data (e.g., means ± SD for yield per treatment) are provided. Reporting only eigenvalues and regression models is insufficient. Please include basic agronomic statistics, such as average yield per tree or per hectare across treatments.
12. Lines 445–466 (Discussion – Foliar Content)
    The discussion largely confirms previous literature but does not critically address unexpected findings, such as Zn-Mo antagonism or chlorophyll a decline at high N rates. Consider discussing study limitations and physiological explanations.
13. General (Practical Implications)
    There is no assessment of the economic feasibility or environmental risks of the high fertilization rates used (e.g., 250 kg N/ha). As this is a practical horticultural study, a brief analysis of cost-efficiency and sustainability is necessary.

Author Response

Comment 1:Line 62–64 (Introduction)
The study objective is too general and lacks a clearly formulated hypothesis. It is recommended to explicitly state the research question and provide a testable hypothesis, such as: "We hypothesize that combined N–Mo–Zn fertilization will significantly improve physiological parameters and yield."

Response 1: The objective and a clearly stated, testable hypothesis have been added to the introduction section, specifically in line 59 to 63 of the revised manuscript.

 

Comment 2: Lines 78–83 (Experimental Design)
The use of a Taguchi L16 design is not sufficiently justified. Why was this method chosen over a full factorial or randomized block design? This is important, especially given that Taguchi designs typically assume additive effects, yet the authors report interactions.

Response 2: Tank you for your important observation. A justification for the use of the Taguchi ñ16 designed has been added (lines 86 to 93). Additionally, the statical analysis section explains how the data were analyzed.

 

Comment 3: Line 81
The statement "77% applied to the soil and 33% as foliar fertilization" is mathematically incorrect. The sum exceeds 100%. Please clarify whether this refers to the number of applications or the proportion of total nutrient mass.

Response 3: Thank you for your observation. The sentence has been correct in the revised manuscript to clarify the intended meaning and resolve the mathematical inconsistency. (lines 89 to 90)

 

Comment 4: Tables 1 and 2
The reported fertilizer levels are given both as molar concentrations and as kg/ha, but no clear conversion or explanation is provided. This makes it difficult to assess the agronomic relevance. A table linking solution concentrations to field application rates would be helpful.

Response 4: Thank you for your suggestion. A new tale 3 has been added to the manuscript, providing the corresponding conversion between molar concentrations and field application rates kgha^-1, to improve clarity and agronomic relevance

 

Comment 5: Line 117 (Nitrate Determination)
The method for NO₃ determination is described briefly but lacks detail about calibration standards, validation procedure, and accuracy. Since nitrate is a central variable, the analytical protocol must be more rigorous and reproducible.

Response 5: The methodology for nitrate determination has been revised and expanded in the manuscript to include details on calibration standards, validation procedures and accuracy. These improvements are now reflected in lines 126 to 138

 

Comment 6: Lines 238 onward (Section 3.1 – Foliar Nutrition)
The interpretation relies heavily on eigenvalue thresholds, but there is no classical statistical analysis such as mean comparisons, ANOVA, or standard deviations. This reduces the transparency and reliability of the results.

Response 6: To improve the transparency and statical robustness of the results, new tables 5, 7 and 9 have been added. These include probability values from response surface regression analysis related to foliar nutrient content, along with standard deviations and f-Values where applicable.

 

Comment 7: Tables 4 and 5
The tables contain key numeric data, but units are missing in some cases, and statistical significance is indicated only vaguely (e.g., * or **). Please provide full units, clarify significance levels, and present actual p-values where possible.

Response 7: The response 6 may complement your question. In addition, the results section has been rewritten to provide a clearer explanation of the initial tables.

 

Comment 8: Figures 1–4 (Response Curves)
While trends are shown graphically, the absence of error bars, R² values, and significance markers weakens the conclusions. Add statistical annotations to confirm model fit and biological relevance of the response surfaces.

Response 8: The R2 values for each model are already included in the corresponding tables. The figures are intended to visually represent the response surface trends derived from regression models, which is why they do not include error bars. However, the statical significance and model fir are fully addressed in he is accompanying tables and tex.

 

Comment 9: Lines 317–349 (Enzymatic Activity)
Although changes in enzyme activities (NR, urease) are reported, the physiological and agronomic significance of these findings is not adequately discussed. Please connect the enzyme data to real-world outcomes, such as nitrogen uptake or growth.

Response 9: Additional references and discussion have been included in line 534-549 to better explain the physiological and agronomic relevance of the enzymatic activity results.

 

Comment 10: Lines 393–396 (Zinc Deficiency)
The statement that N and Mo increase Zn deficiency contradicts earlier claims of nutritional improvement. This logical inconsistency needs to be addressed. Is the deficiency real or a relative effect based on plant uptake ratios?

Response 10: This point has been addressed and clarified in the revised manuscript, specifically in lines 575-582.

 

Comment 11: Table 6 (Yield Parameters)
No absolute yield data (e.g., means ± SD for yield per treatment) are provided. Reporting only eigenvalues and regression models is insufficient. Please include basic agronomic statistics, such as average yield per tree or per hectare across treatments.

Response 11: Thank you for your observation. while eigenvalues and regression models are used to interpret treatment effects, relevant yield date are also provided in table 8, which includes R2, means and observed yield values ranging from 7.9 to 425.4 kg ha-1. Additionally, the frequency analysis indicates than nitrogen had the strongest effect (frequency of 4), followed by molybdenum and zinc while the Zn—Mo combination did not show a significant response. These values offer practical agronomic context and support the interpretation of treatment impact.

 

Comment 12: Lines 445–466 (Discussion – Foliar Content)
The discussion largely confirms previous literature but does not critically address unexpected findings, such as Zn-Mo antagonism or chlorophyll a decline at high N rates. Consider discussing study limitations and physiological explanations.

Response 12: The discussion has been revised and expanded in lines 551-574. This also complements the response to comment 10.

 

Comment 13: General (Practical Implications)
There is no assessment of the economic feasibility or environmental risks of the high fertilization rates used (e.g., 250 kg N/ha). As this is a practical horticultural study, a brief analysis of cost-efficiency and sustainability is necessary.

Response 13: Additional information has been included regarding the actual amount to fertilizer used during the experiment, which is significantly lower than the 250 kg ha N mentioned. The applies doses were optimized, with 65% applied to the soil and 33% as foliar fertilization, increasing nutrient use efficiency. A description of the optimal doses uses n this study s provided in lines 464 to 474.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The authors have addressed the previous comments, and the manuscript is now in good shape; I recommend its publication in this journal after minor revision.

Minor Revision Suggestion:

Line 138: "ppm" is not an internationally recognized SI unit and should be replaced with "mg kg⁻¹" for standardization.

Author Response

Comment 1: Line 138: "ppm" is not an internationally recognized SI unit and should be replaced with "mg kg⁻¹" for standardization.

Response 1: Thank you for your observations. The unit has been corrected in the revised version of the manuscript, replacing "ppm" with "mg kg^-1" to comply with International System of Units (SI) standards. We sincerely appreciate your contributions and the time you dedicated to reviewing this article.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The authors have made the required corrections

Author Response

Comment 1: The authors have made the required corrections.

Response 1: Thank you for you review. We appreciate your time. We hoe the revised manuscript now meets the journal´s standards.

Reviewer 3 Report

Comments and Suggestions for Authors

1. Line 14: Typo in unit — "mg ka-1de" should be corrected to mg kg⁻¹.
2. Line 19: Unclear grammar — "were also positively affected was observed" should be revised for clarity, e.g., positive effects were observed with increased N and Mo doses.
3. Line 30: Typographical error — "int eh human diet" should be corrected to in the human diet.
4. Line 41: Reference [3] is not properly punctuated — consider adding a period or clarifying the sentence structure.
5. Line 85: Typo — "desing" should be design.
6. Line 97: Missing comma after "manual sprayer" — revise to ensure smooth sentence flow.
7. Line 138: The equation for nitrate concentration lacks unit clarity; please indicate the source or reference for this method explicitly.
8. Lines 186–187: Definitions of Chl a, Chl b, and Cx+c are not formatted consistently; recommend aligning them for clarity and professionalism.
9. Line 215: Typo — "Octuber" should be corrected to October.
10. Line 259: Typo — "concertation" should be concentration.
11. Line 267: The abbreviation "VR" (used for value ranges) should be defined or removed for clarity.
12. Line 303: Redundant phrase — "interaction antagonistic interaction" should be reduced to simply antagonistic interaction.
13. Line 323: Subject-verb agreement — "N present an inflection point" should be revised to N presents or an inflection point is observed with N.
14. Line 354: Inconsistent spacing — "Figure 5a and 5 b" should be corrected to Figure 5a and 5b.
15. General: The manuscript contains numerous typographical and formatting issues (e.g., inconsistent spacing, punctuation errors, table misalignments) that should be addressed through thorough proofreading before publication.
16. Line 87: While the Taguchi L16 design is mentioned, a rationale for selecting this specific orthogonal array over others is missing — please justify the choice.
17. Line 93: The article refers to Tables 1–3 but does not adequately explain how the fertilizer levels were determined. Were these based on previous studies, local standards, or preliminary trials?
18. Line 107: Foliar sampling was conducted only once (end of June). A single sampling may not reflect the full dynamics of nutrient uptake over time — please comment on this limitation.
19. Line 140: Enzyme activity was evaluated using nitrate reductase, but no control or baseline for natural activity levels is described. Was there a non-treated group for comparison?
20. Line 156: The incubation step mentions "in the darkness" twice — unclear if this is meant to emphasize importance or redundancy; more importantly, the reason for dark incubation could be briefly explained.
21. Line 215: Visual evaluation of foliar development is subjective. Please clarify if assessments were conducted blind or by multiple evaluators to avoid bias.
22. Line 221–222: The paper combines Taguchi design with multiple regression and PCA-like eigenvalue analysis. This is unusual — justification and methodological coherence should be more explicitly discussed.
23. Line 247: Foliar nutrition analysis focuses on eigenvalue thresholds, but the biological significance of some variables (e.g. Cu or Na changes) is unclear — were these changes agronomically relevant?
24. Line 259: The nitrogen response dose is described as “optimal” but is based only on concentration, not on yield or economic return — consider discussing this aspect.
25. Line 266: The claim that nitrate levels exceeded reference values should be backed by a citation or regional norm for pecan trees.
26. Line 306: The stated “synergistic effect” between Zn-Mo and Zn on P levels may be over-interpreted — visual inspection of Figure 2f shows a modest increase; consider tempering the language or quantifying the synergy.
27. Line 314–317: Calcium responses are discussed, but potential mechanisms for decreased Ca at higher N doses are not explained — please elaborate.
28. Line 340–349: The discussion of enzymatic activity could benefit from connecting results to physiological outcomes — e.g., how nitrate reductase activity translated to plant performance.
29. Line 353–356: The conclusion that 20 kg/ha Zn optimizes enzyme performance seems oversimplified — was this value derived from model maxima, or field-observed plateaus?
30. Line 336: The recommendation for application doses lacks a discussion on cost-effectiveness or practical implementation in commercial orchards — consider adding a brief applied perspective.

Author Response

Comments: 1,2,5,6,9,10 and 15: The manuscript contains numerous typographical and formatting issues (e.g., inconsistent spacing, punctuation errors, table misalignments) that should be addressed through thorough proofreading before publication.

Response:  Thank you for your observation. All typographical and formatting errors noted in the specific comments, as well as other identified through a thorough review of the manuscript, have been corrected. The entire document has been carefully proofread to ensure consistency in spacing, punctuation, and table formatting. We believe the revised version now meets the journal ´s editorial standards.

Comment 3: (Line 19) Unclear grammar — "were also positively affected was observed" should be revised for clarity, e.g., positive effects were observed with increased N and Mo doses.

Response 3: The sentence has been restructured for clarity. Lines 18 and 19.

Comment 4: (Line 41) Reference [3] is not properly punctuated — consider adding a period or clarifying the sentence structure.

Response 4: The punctuation for reference [3] has been corrected, and sentence structure has been revised to improve clarity (Line 42)

Comment 7: (Line 138) The equation for nitrate concentration lacks unit clarity; please indicate the source or reference for this method explicitly.

Response 7:  The unit the equation has been corrected to indicate that the nitrate concentration corresponds to foliar tissue and is expressed in mg kg ha-1, and the source has been provided. (143 to 146)

Comment 8: (Lines 186–187) Definitions of Chl a, Chl b, and Cx+c are not formatted consistently; recommend aligning them for clarity and professionalism.

Response 8: The formatting of the definitions for Chl a, Chl b and Cx has been adjusted to ensure consistency clarity, and more professional presentation. (lines 199 to 201)

Comment 11: (Line 267) The abbreviation "VR" (used for value ranges) should be defined or removed for clarity.

Response 11: The abbreviation VR has been clearly defined in the corresponding tables.

Comment 12: (Line 303) Redundant phrase — "interaction antagonistic interaction" should be reduced to simply antagonistic interaction.

Response 12: The redundant phrase has been corrected, and the sentence now reads simply as “antagonistic” interaction to improve clarity and precision. (line 324)

Comment 13: (Line 323) Subject-verb agreement — "N present an inflection point" should be revised to N presents or an inflection point is observed with N.

Response 13: The subject-verb agreement has been corrected. ( lines 348 and 349)

Comment 14: (Line 354) Inconsistent spacing — "Figure 5a and 5 b" should be corrected to Figure 5a and 5b.

Response 14: The spacing issue has been corrected. (Line 378)

Comment 16: (Line 87) While the Taguchi L16 design is mentioned, a rationale for selecting this specific orthogonal array over others is missing — please justify the choice.

Response 16: Thank you for your observation. A justification has been included in the revised text. The choice of the Taguchi L16 orthogonal design was based on the need to simultaneously evaluate four factors at four levels each, while maintaining a balance between the number of treatments, experimental efficiency, and statical analysis capacity. Unlike a full factorial design (4⁴ = 256 treatments), the L16 array allows a reduction in the number of experimental combinations to just 16 treatments. This reduction is particularly valuable in agronomic field studies where resources, time and experimental area are limited. (lines 86 to 94)

Comment 17: (Line 93) The article refers to Tables 1–3 but does not adequately explain how the fertilizer levels were determined. Were these based on previous studies, local standards, or preliminary trials?

Response 17: We appreciate your observation. In the revised version of the manuscript, we clarified that the combinations of fertilization treatments shown in tables 2 and 3 were determined using a TaguchiL16 design, aimed at maximizing experimental efficiency and enabling the simultaneous evaluation of multiple factors. The specific fertilizer levels presented in Table 1 were selected based on a combination of previous field studies-Both published and unpublished-local agronomic recommendations, and over ten years of experimental data collected from commercial pecan orchards. 

Comment 18: (Line 107) Foliar sampling was conducted only once (end of June). A single sampling may not reflect the full dynamics of nutrient uptake over time — please comment on this limitation.

Response 18:  We acknowledge this limitation. Foliar sampling was conducted only once at the end of june due to restrictions imposed by the COVID-19 pandemic. Nevertheless, this timing was chosen because it coincides with a critical stage of the crop´s physiological development (nut-filling), providing representative information on the nutritional status during a key phase 

Comment 19: (Line 140) Enzyme activity was evaluated using nitrate reductase, but no control or baseline for natural activity levels is described. Was there a non-treated group for comparison?

Response 19: In this study, 16 treatments were evaluated according to the Taguchi L16. Treatment 1 served as the control group, with no application of N, Mo o Zn fertilization, and was used as a reference to compare baseline enzymatic activity against the treated groups.

Comment 20: (Line 156) The incubation step mentions "in the darkness" twice — unclear if this is meant to emphasize importance or redundancy; more importantly, the reason for dark incubation could be briefly explained.

Response 20: The error of repeating “in the darkness” twice as been corrected. Additionally, a brief explanation was added to clarify the importance of performing the procedure in the dark.(Lines 166 to 169)

Comment 21: (Line 215) Visual evaluation of foliar development is subjective. Please clarify if assessments were conducted blind or by multiple evaluators to avoid bias.

Response 21: To minimize in the visual evaluation of foliar development, a prior training protocol was implemented to standardize criteria among evaluators. Observations were helped reduce subjectivity and improve data reliability. (lines 228 to 234)

Comment 22: (Line 221–222) The paper combines Taguchi design with multiple regression and PCA-like eigenvalue analysis. This is unusual — justification and methodological coherence should be more explicitly discussed.

Response 22: The wording has been improved to avoid ambiguity in the statical analysis. The response surface analysis was performed using least squares regression. This approach has been successfully applied in recent agronomic studies aiming to integrate experimental efficiency with deeper analysis of physiological and productive responses (Noperi-Mosqueda et al., 202; Oviedo-Mireles et al., 2021). (lines 241 to 260)

Comment 23: (Line 247) Foliar nutrition analysis focuses on eigenvalue thresholds, but the biological significance of some variables (e.g. Cu or Na changes) is unclear — were these changes agronomically relevant?

Response 23: The Na variable was not selected for further analysis, as its frequency in the eigenvector loading was below the threshold value of 11. In contrast, -cu was selected, with a frequency of 13, indicating a consistent response across treatments. N was identified as the factor with the greatest effect on Cu content. A discussion has been added to the manuscript addressing the biological relevance of both Mg and Cu in plant nutrition and their role in physiological processes (549 to 556)

Comment 24: (Line 259) The nitrogen response dose is described as “optimal” but is based only on concentration, not on yield or economic return — consider discussing this aspect.

Response 24: The term “optimal” was not intended to imply agronomic or economic optimization. It has been corrected in the revise manuscript to ref instead to the nitrogen response range, based on physiological variables. Line 282.

Comment 25: (Line 266) The claim that nitrate levels exceeded reference values should be backed by a citation or regional norm for pecan trees.

Response 25:  There was a wording error in the original text, which has been corrected in the revised version of the manuscript. The statement has been removed to avoid misinterpretation. (line 287).

Comment 26: (Line 306) The stated “synergistic effect” between Zn-Mo and Zn on P levels may be over-interpreted — visual inspection of Figure 2f shows a modest increase; consider tempering the language or quantifying the synergy.

Response 26: The wording has been revised in lines 327 to 330 to avoid misinterpretation, moderating the language used and clarity that the increase observed in phosphorus levels was modest.

Comment 27: (Line 314–317) Calcium responses are discussed, but potential mechanisms for decreased Ca at higher N doses are not explained — please elaborate.

Response 27: An explanation of the potential effects that may account for the decrease in calcium under hug nitrogen doses has been added. This information has been incorporated into the discussion section (lines 538 to 541)

Comment 28: (Line 340–349) The discussion of enzymatic activity could benefit from connecting results to physiological outcomes — e.g., how nitrate reductase activity translated to plant performance.

Response 28: An explanation has been added in the discussion section (lines 581 to 585) regarding how NR activity directly impacts the plant´s physiological performance. A clear relationship was established between higher NR activity and variables such as leaf size, canopy coverage, and the percentage of fruitful shoots, which in turn was reflected in improvements in pomological parameters.

Comment 29: (Line 353–356) The conclusion that 20 kg/ha Zn optimizes enzyme performance seems oversimplified — was this value derived from model maxima, or field-observed plateaus?

Response 29:  A more detailed explanation regarding the doses of each evaluated factor, including Zn, has been added. This information can be found in the discussion section, in lines 617 to 636 of the revised manuscript.

Comment 30: (Line 336) The recommendation for application doses lacks a discussion on cost-effectiveness or practical implementation in commercial orchards — consider adding a brief applied perspective.

Response 30: An additional section has been included in the discussion addressing the practical feasibility of the proposed application doses and their applicability under typical operational conditions in commercial pecan orchards. This information can bee found in lines 617 to 636 of the revised manuscript.

 We sincerely thank you for your comments, observations, and the time you dedicated to reviewing this manuscript. Your contributions have been highly valuable in improving the quality, clarity, and overall strength of the work presented.

 

Author Response File: Author Response.pdf