Spatial and Temporal Nutrient Dynamics and Water Management of Huanglongbing-Affected Mature Citrus Trees on Florida Sandy Soils
Round 1
Reviewer 1 Report
First of all, I would like to congratulate the authors for their work. I am grateful for the opportunity to review this article.
The article focuses on an important topic.
Authors should improve the description of treatments. They must have a clear code for each treatment, to be used throughout the text and which is easy to understand. Apparently, “2x” is not twice as much as “1x”, but rather an application to leaves and soil, while 1x is an application to leaves. This will make the article easier to read.
Now I add some specific comments:
Lines 27-29: “Higher soil acidity was detected when trees received the highest micronutrient rate and the topsoil layers (0–15 cm) as compared with the middle (15–30 cm) and the lowest soil layer (30–45 cm) layers.” The second part of that sentence cannot be understood well.
Lines 32-34: “stomata conductance (gs), and sap flow were also affected by the highest micronutrient rate as compared with the other rates of treated trees in the soil-plant-atmosphere continuum.” The sentence cannot be understood well.
Line45: “(references)” This word seems to indicate that one of the authors felt the just need to include some reference. It hasn't been done, but it needs to be.
Line 53-54: Format change (line spacing)
Lines 56-58: “ …the decline in FRLD, …. is severely disrupted” (???). Authors should review this sentence.
Lines 58-60: “Agriculture consumes more than 70% of freshwater withdrawals and …; this has been associated with the decline in surface water , water quality”. Authors should review this sentence.
Lines 121-127: The experimental design is unclearly described. I did not understand which micronutrients were actually applied in each treatment and when they were applied. I think the authors, knowing what they did, underestimated the fact that readers need to understand the authors' code. This is even more evident in lines 415-416, where the authors assume that the reader knows what "leaf 1×" and "soil-applied 1× (2×)" mean, without even writing what was applied. The conclusions should be clear in themselves, without the reader having to look for the Material and Methods.
Line 447: Eliminate “Review article”
Line 450: Eliminate “Comparative”
Comments for author File: 
Comments.pdf
Author Response
Dear reviewer,
We have provided the comment and edits as suggested.
The article focuses on an important topic.
Authors should improve the description of treatments. They must have a clear code for each treatment, to be used throughout the text and which is easy to understand. Apparently, “2x” is not twice as much as “1x”, but rather an application to leaves and soil, while 1x is an application to leaves. This will make the article easier to read.
Response 1: The sentence has been edited as follows: The micronutrients were applied to foliage and soil as follows: foliar only, foliar and soil-applied, and foliar and soil-applied (2×), (each treatment had 9 kg ha-1 year-1 of Mn and Zn each and 2.2 kg ha-1 year-1 of B). All phrases that pertained to these treatments were also edited in the manuscript accordingly.
Now I add some specific comments:
Lines 27-29: “Higher soil acidity was detected when trees received the highest micronutrient rate and the topsoil layers (0–15 cm) as compared with the middle (15–30 cm) and the lowest soil layer (30–45 cm) layers.” The second part of that sentence cannot be understood well.
Response 2: “Higher soil acidity was detected when trees received the highest micronutrient rate and in the . . .
Lines 32-34: “stomata conductance (gs), and sap flow were also affected by the highest micronutrient rate as compared with the other rates of treated trees in the soil-plant-atmosphere continuum.” The sentence cannot be understood well.
Response 3: The sentence was re-written as “Invariably, the water dynamics: stem water potential (y stem), stomata conductance (gs), and sap flow were also negatively affected when trees received foliar and soil (2×) treatment as compared with the others in the soil-plant-atmosphere continuum.”
Line 45: “(references)” This word seems to indicate that one of the authors felt the just need to include some reference. It hasn't been done, but it needs to be.
Response 4: Reference included at the end of the sentence. “Many of these symptoms have been associated with reduced nutrient concentrations in HLB-affected trees [2].”
Line 53-54: Format change (line spacing)
Response 5: Format changed.
Lines 56-58: “ …the decline in FRLD, …. is severely disrupted” (???). Authors should review this sentence.
Response 6: Meanwhile, following the infection of citrus trees with CLas, FRLD decline, water and nutrient uptake, xylem sap flow, and phloem movement is severely disrupted [12,13].
Lines 58-60: “Agriculture consumes more than 70% of freshwater withdrawals and …; this has been associated with the decline in surface water, water quality”. Authors should review this sentence.
Response 7: Agriculture consumes more than 70% of freshwater withdrawals and 90% of consumptive water use; this results in a decline in surface water flow, groundwater depletion, water quality, and triggers eutrophication worldwide [14,15].
Lines 121-127: The experimental design is unclearly described. I did not understand which micronutrients were actually applied in each treatment and when they were applied. I think the authors, knowing what they did, underestimated the fact that readers need to understand the authors' code. This is even more evident in lines
Response 8: The sentence was improved as “Each experimental unit of the three N rates received either control, foliar only, foliar and soil-applied and foliar and soil-applied (2×) micronutrient treatments.”
415-416, where the authors assume that the reader knows what "leaf 1×" and "soil-applied 1× (2×)" mean, without even writing what was applied. The conclusions should be clear in themselves, without the reader having to look for the Material and Methods.
Response 9: We edited the following sentence as: “The information in the current study suggested N rate 224 kg ha-1 year-1 and foliar (9 kg ha-1 year-1 each of Mn and Zn nutrients)only, and soil-applied (9 kg ha-1 year-1 each of Mn and Zn nutrients) showed positive impacts on root growth and nutrient availability in the soil.”
Line 447: Eliminate “Review article”
Response: “Review article” deleted
Line 450: Eliminate “Comparative”
Response: “Comparative” deleted
With regards,
On behalf of the authors
Author Response File: Author Response.pdf
Reviewer 2 Report
The abstract has too many methodological details that can not be easily understand, I suggest to be simplified.
In the hypothesis number 2, "timely application of essential nutrients to minimize nutrient leaching and the effect of soil inmovilization in response to soil chemical reactions", I can understand that you can build a hypothesis to minimize the effect of nutrient leaching, but the effect of soil inmovilization in a sandy soil, is hard to believe. Also, in the results and conclusion there is no reference to soil inmobilization. In this second hypothesis you should include: in citrus trees affected by HLB.
In general, the results are associated to soil measurements of the applied treatments. So in the conclusiones, the final phrase "The study could have also shown a significant impact on young established groves as these nutrients contribute to and promote vegetative growth on the trees", since you did not measure any vegetative growth, this sentence must be omited.
Did HLB symptoms diminished in some treatments? I mean foliar or fruit symptoms, are well documented in the introduction, buy without mention in the results (figures or tables).
In Figure 5 there is no explanation about numbers: 1, 2, 3 and 4.
In the references, in some of them, there is no information about the journal, volume and pages. You should comlete according to instructions to the authors of this journal.
Author Response
Reviewer suggestion
Dear reviewer,
Thank you for your comments and suggestion regarding the content of the manuscript. All comments and suggestions are addressed in the manuscript.
The abstract has too many methodological details that can not be easily understand, I suggest to be simplified.
Response: Based on you and the suggestion from the other reviewers, the abstract was edited in its most simplified version.
In the hypothesis number 2, "timely application of essential nutrients to minimize nutrient leaching and the effect of soil inmobilization in response to soil chemical reactions", I can understand that you can build a hypothesis to minimize the effect of nutrient leaching, but the effect of soil inmovilization in a sandy soil, is hard to believe. Also, in the results and conclusion there is no reference to soil inmobilization. In this second hypothesis you should include: in citrus trees affected by HLB.
Response 1: the sentences in the introduction and conclusion part have been edited as suggested.
In general, the results are associated to soil measurements of the applied treatments. So in the conclusiones, the final phrase "The study could have also shown a significant impact on young established groves as these nutrients contribute to and promote vegetative growth on the trees", since you did not measure any vegetative growth, this sentence must be omited.
Response 2: The sentence has been improved based on our findings and suggests the possible future prospective focus of a study. The study could have also shown a significant impact on young established citrus groves as these nutrients contribute to promoting the establishment of FRLD and boost the availability of soil nutrients with emphasis on the root-zone soil acidity.
Did HLB symptoms diminished in some treatments? I mean foliar or fruit symptoms, are well documented in the introduction, but without mention in the results (figures or tables).
Response 3: Trees under foliar and foliar and soil applied micronutrients (table 2 and figure 4) had significant water use efficiency (Taable 3 and Figure 6 and 7) and available soil nutrients as compared to the untreated trees. The details are included in the result and discussion part of each section.
In Figure 5 there is no explanation about numbers: 1, 2, 3 and 4.
Response 4: Explanation of each treatment now has been included: “Treatments: closed circles (control), open circles foliar only, closed triangles foliar and soil-applied, and open triangles foliar and soil-applied (2×), (treatment had 9 kg ha-1 year-1 of Mn and Zn each and 2.2 kg ha-1 year-1 of B).”
In the references, in some of them, there is no information about the journal, volume and pages. You should comlete according to instructions to the authors of this journal.
Response 5: All References are edited as suggested throughout the list of references.
With regards,
On behalf of the authors
Author Response File: Author Response.pdf
Reviewer 3 Report
Sir
The reviewed paper has been attached herewith and paper need revision.
The concept of the paper is very good. The lot of quality data have been generated by the authors, which need appreciations. The paper will be very useful for other researcher. The presentation of the paper need to be improved to improve the quality of the paper. Number of the queries have been raised in the paper to improve the quality of paper.
Regards
Comments for author File: Comments.pdf
Author Response
Dear reviewer,
Thank you for your comments and suggestion regarding the content of the manuscript. All comments and suggestion are addressed in the manuscript.
Line 14-15: rewrite these lines in a simple way “Huanglongbing (HLB; citrus greening) is a disease that has no known control mechanism discovered thus far once citrus trees are infected with the phloem-limited, Gram-negative bacteria Candidatus Liberibacter asiaticus (CLas).
Response 1: Once a citrus tree is infected with the phloem-limited, Gram-negative bacteria Candidatus Liberibacter asiaticus (CLas), Huanglongbing (HLB; citrus greening) has no known control mechanism discovered thus far.
Line 23-26: rewrite these lines “assigned in a split-split plot design applied in three split applications annually. Micronutrients were applied to foliage and soil as follows, foliar only 1× (1×), foliar 1× and soil-applied 1× (2×), and foliar 1× and soil-applied 2× (3×) of (1× = 9 kg ha-1 year-1 of Mn and Zn each and 2.2 kg ha-1 year-1 of B).”
Response 2: the quantity is the same in both foliar, soil applied, and the soil is doubled in the third treatments. The statement is rewritten as follows: “… The micronutrients were applied to foliage and soil as follows: foliar only, foliar and soil-applied, and foliar and soil-applied (2×), (treatment had 9 kg ha-1 year-1 of Mn and Zn each along with 2.2 kg ha-1 year-1 of B).
Line 35: Add conclusion lines:
Response 3: Concluding remarks added as “Split application of nutrients had significant effect in FRLD growth, retaining soil applied nutrients within the active root zone, and improved water use efficiency.”
Line 45: use standard method
Response 4: edited as suggested. “… associated with reduced nutrient concentrations in HLB-affected trees [2].
Line 46-47: Rewrite these lines.
Response 5: The lines edited as “… disease control [3], because nutrients influence plant, … [4,5].”
Response 6: reference crop evapotranspiration (ETo) and crop coefficient (Kc)
Line 52: “… evapotranspiration (ETc) and crop coefficient (Kc)…”
Response 7: edited as “… reference crop evapotranspiration (ETo) and crop coefficient (Kc)…”
Line 79-86: “… to (1) determine if recurrent applications … “.
Response 8: reedited as “… to (1) determine applications of essential nutrients increase soil available N, Mn, Zn uptake and accumulation with an emphasis on the root-zone soil pH; (2) compare foliar only or the combination of foliar and soil-applied essential nutrients improve the soil nutrient availability and accumulation, and reduce leaching of these nutrients beyond the root zone; (3) evaluate foliar nutrient coupled with soil applications reduce the leaching of nutrient and improve water use efficiency in HLB-affected citrus trees beyond the root zone and the soil-plant-atmosphere continuum, respectively.
Line 93: “… weather station; (https://fawn.ifas.ufl.edu/data/reports) 93 located about 200 m from the study site.”
Response 9: This link is not a citation; it is just to indicate where the weather data were extrapolated.
Line 97: Merge the graphs (Figure 1A and B).
Response 10: The graph merged as suggested into (Figure 1).
Line 111: “… trees had a cycle threshold 110 value of 24.7 ± 0.19,…”
Response 11: edited as “…value of 24.7 ± 0.19 cycle threshold, “
Line 139: give ref in uniform way (standard way)
Response 12: The link is to show where a reader can get the app; a reference is also included at the end of the sentence “… (http://smartirrigationapps.org/) available on the mobile device operating systems: iOS and Android packages [6].”
Line 137: Method of organic matter determination is missing
Response 13: The study site soil characteristics is purely sand (98%). Therefore, it barely had organic matter content to consider in the current study.
Line 185: “… with foliar only (9), foliar 9 and soil 9 (18), and foliar 285 (9) and soil 18 (27) kg ha-1 year-1 Mn …”
Response 14: These are the corresponding portrayal of the micronutrient treatments: control, foliar only, foliar and soil-applied, and foliar and soil-applied (2×) micronutrient treatments.
Line 338-339: change in soil pH 6.1 to 5.2 by the addition of Sulphur. kindly check it. Yes Sulphur play imp role in declining soil pH. But it is very drastic change at all depth
Response 15: Yes, I agree on your claim that the elemental S plays significant role in dropping the soil pH. The Florida sandy soil has a soil pH around the neutral. What we found in the last 5 years study on sandy soils is that the top (0-15) cm was the most affected on the treated trees. The treated trees ranges from as low as 4-soil pH in some instances. Yet, we also found the bottom layers (15-30 and 30-45 cm) had been affected progressively through time too as compared with the trees under the control trees.
Line 442-547: Reference correction
Response 16: All reference edited as suggested in all cases.
Line 547-552: Figures are very confusing no need to give mean daily data. it can be replaced with standard weeks. Both figures can be be merged into one figure. Correct units, omit footnote
Response 17: Unit corrected and footnote deleted as suggested.
Line 592-593: What is a,b,c, and d and what is the role factor season and micro. Data replaced with standard weeks.
Response 18: The details are mentioned in the footnote of figure 5 as, Treatments: closed circles (control), open circles foliar only, closed triangles foliar and soil-applied, and open triangles foliar and soil-applied (2×), (treatment had 9 kg ha-1 year-1 of Mn and Zn each and 2.2 kg ha-1 year-1 of B). Bars are the mean seasonal fine root length density (n = 8 trees) ± SEM. Asterisks: *, **, and *** represent ANOVA significance level at p ≤ 0.05, 0.001, and < 0.0001, respectively.
Line 614-616: both predicted and observed values are missing from the graphs.
Response 19: the picture type was converted into a bitmap to clearly portray the predicted and observed values of each panel in figure 7.
With regards,
On behalf of the authors
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The authors were asked to do a global review of the project. It seems that what they did was correct some errors pointed out as example. A global review remains to be done.
Author Response
Dear reviewer,
Thank you for your professional comments and suggestions. I have addressed all the suggestion as per the recommendations. The results have also been updated as suggested.
With best,
on behalf of the authors
Reviewer 2 Report
Dear authors.
All the suggestions were aborded.
Best
Reviewer
Author Response
Dear reviewer,
Thank you for your invaluable comments and suggestions. I have addressed all the suggested as per the recommendation.
With best,
on behalf of the authors
Author Response File: 
Author Response.docx
Reviewer 3 Report
Paper is Revised and can be accepted.
Best of Luck
Author Response
Dear reviewer,
I have worked on the methodology section and added a table (Table 2) for clarification of the method and rate of application of each nutrient under the study.
With regards,
Atta,
on behalf of the authors
Author Response File: Author Response.docx
Round 3
Reviewer 1 Report
The authors continue not to change the article according to the recommendations. The quality of the article still does not correspond to the level that the journal must maintain. The description of the trial remains insufficient. The authors do not describe in what forms the nitrogen was applied. It is also not described whether phosphorus was applied and, if so, in what amount and how it was applied. The micronutrient treatments are written in a way that can have different interpretations. It is not clear whether the soil application is a complement to the foliar application or if the foliar application dose was divided in the 3rd treatment between foliar and soil applications. I think the best thing would be to make a table describing the application treatments and the amounts of applied fertilizers.
Comments for author File: Comments.pdf
Author Response
Hello reviewer,
I have added a table to depict the trial and how each of the nutrients was applied. I have also responded to all the suggestions point-by-point.
With regards,
Atta,
on behalf of the authors
Author Response File: Author Response.docx
