Spatiotemporal Root-Trait Plasticity Underpins Almond Yield Stability and Enhanced Water and Nitrogen Use Efficiency Under Prolonged Fertigation Reduction
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsPlease brief the title of the manuscript, which should be more interesting for readership ‘’Horizontal, vertical, and temporal root-trait responsiveness underpin sustained almond yield during four seasons of irrigation and/or nitrogen reductions.
Spatiotemporal Root Trait Alterations Drive Almond Yield Stability Under Prolonged Water and Nitrogen Deficits
‘’Horizontal, vertical, and temporal root-trait responsiveness support almond yield stability under prolonged water and nitrogen deficits
Please write units as ha-1 and kg ha-1 . Check whole paper. (15 ML/ha/season water and 300 kg/ha/sea-14 son nitrogen) to −W−N (10.5 ML/ha/season water and 160 kg/ha/season nitrogen; 30% re-15 duction of irrigation and 46% reduction of nitrogen). kg nitrogen/ha/season
At the end of the introduction, better clarify the hypothesis; do not repeat treatments here. With a hypothesis, write the objective of the study. We tested the hypothesis with a four-year 101 f ield experiment involving four treatments (i.e., commercial standard practice, 30% 102 reduction in irrigation, 46% reduction in nitrogen application, and a combination of the 103 two), where the treatment-induced adjustments of root trait and tree water use in a 104 commercial production environment were compared.
2.1. Experimental site, plant materials and treatments in the commercial orchard.
In this heading, remove the literature review. Just shortly define the study site, plant materials and soil and environmental conditions.
Soil coring. Change to soil samplings.
Brief the introduction section. First and second paragraphs are too long.
Please improve Figure 1. Figure 2. Figure 3 by bolder lines or may redraw the figure in professional software. I just suggested. If possible, do it.
The conclusion section is missing. Please add it. Short conclusion focusing best treatments and recommendations.
’’ Further improve this paragraph by reading the paper ‘’What should we do for water security? A technical review on more yield per water drop’’ However, it is unclear how resilient the various crop types are in 41 modifying the root system to adapt to the distribution of water and/or nutrients, though 42 clearly, however, this will depend on the delivery system, e.g., full or partial ground cover 43 water application, e.g., through sprays or drip lines, and nutrient application by broadcast 44 or fertigation procedures [1]. To better understand tree crop resilience and how it may be 45 affected by changes in orchard management practices, e.g., changes in irrigation or 46 fertilizer application strategies, it is imperative to have the best possible understanding of 47 the key characteristics of the root system
Comments on the Quality of English LanguageImprove
Author Response
Dear madam/sir,
Thank you for recognising our work on its scientific integrity and the quality of the work and writing. And thank you for kindly helping us improving the manuscript with your suggestions. We have fully revised the manuscript corresponding to your suggestions one by one as follows. Besides, we also produced new Figures 2-4 each is in high resolution TIFF format besides wider arrows. For the main figures (2-4) we have also removed the parameters on total ‘root length’ and ‘root area’, and supplied the original Figures with all pamaters in the current Supplementary Figures S1-S3. We also added the Supplementary Table S1 supplying the data set of all traits, and added the statistics subsection as ‘4.4. Statistical analyses’. We added the Conclusions section and the Supplementary Materials section. We shortened the first few paragraphs in the Introduction, extended the key parts in the Results section and Discussions section, and added new literatures accordingly.
Please feel free to let us know if you have any questions and/or more suggestions. We sincerely acknowledge your time and effort.
Thank you.
Shuangxi Zhou and all authors
Comment 1:
Please brief the title of the manuscript, which should be more interesting for readership ‘’Horizontal, vertical, and temporal root-trait responsiveness underpin sustained almond yield during four seasons of irrigation and/or nitrogen reductions.
Spatiotemporal Root Trait Alterations Drive Almond Yield Stability Under Prolonged Water and Nitrogen Deficits
‘’Horizontal, vertical, and temporal root-trait responsiveness support almond yield stability under prolonged water and nitrogen deficits
Response 1: Thanks, and we fully agree. Now the title is ‘Spatiotemporal Root-trait Plasticity Underpins Almond Yield Stability Under Prolonged Water and Nitrogen Reductions’.
Comment 2
Please write units as ha-1 and kg ha-1 . Check whole paper. (15 ML/ha/season water and 300 kg/ha/sea-14 son nitrogen) to −W−N (10.5 ML/ha/season water and 160 kg/ha/season nitrogen; 30% re-15 duction of irrigation and 46% reduction of nitrogen). kg nitrogen/ha/season
Response 2: Thanks, and we have revised all of them.
Comment 3
At the end of the introduction, better clarify the hypothesis; do not repeat treatments here. With a hypothesis, write the objective of the study. We tested the hypothesis with a four-year 101 f ield experiment involving four treatments (i.e., commercial standard practice, 30% 102 reduction in irrigation, 46% reduction in nitrogen application, and a combination of the 103 two), where the treatment-induced adjustments of root trait and tree water use in a 104 commercial production environment were compared.
Response 3: Thanks, and we fully agree. We have revised this paragraph accordingly.
Comment 4
2.1. Experimental site, plant materials and treatments in the commercial orchard.
In this heading, remove the literature review. Just shortly define the study site, plant materials and soil and environmental conditions.
Response 4: Thanks, and we have deleted accordingly.
Comment 5
Soil coring. Change to soil samplings.
Response 5: Thanks, and we have revised all of them.
Comment 6
Brief the introduction section. First and second paragraphs are too long.
Response 6: Thanks, and we have shortened them accordingly and re-structured the section.
Comment 7
Please improve Figure 1. Figure 2. Figure 3 by bolder lines or may redraw the figure in professional software. I just suggested. If possible, do it.
Response 7: Thanks, we re-produced new Figures 2-4 each is in high resolution TIFF format with less parameters besides wider arrows. For the main figures (2-4) we have also removed the parameters on total ‘root length’ and ‘root area’, and supplied the original Figures with all pamaters in the current Supplementary Figures S1-S3.
Comment 8
The conclusion section is missing. Please add it. Short conclusion focusing best treatments and recommendations.
Response 8: Thanks, and we have added the conclusion section as the final section.
Comment 9
’’ Further improve this paragraph by reading the paper ‘’What should we do for water security? A technical review on more yield per water drop’’ However, it is unclear how resilient the various crop types are in 41 modifying the root system to adapt to the distribution of water and/or nutrients, though 42 clearly, however, this will depend on the delivery system, e.g., full or partial ground cover 43 water application, e.g., through sprays or drip lines, and nutrient application by broadcast 44 or fertigation procedures [1]. To better understand tree crop resilience and how it may be 45 affected by changes in orchard management practices, e.g., changes in irrigation or 46 fertilizer application strategies, it is imperative to have the best possible understanding of 47 the key characteristics of the root system
Response 9: Thanks, combining your previous comment with this one we have fully deleted this paragraph.
Comment 10
Comments on the Quality of English Language
Improve
Response 10: Thanks, and we have revised the whole manuscript accordingly.
Author Response File: 
Author Response.docx
Reviewer 2 Report
Comments and Suggestions for AuthorsDear Authors!
You have done a great experimental work over several years. The manuscript is relevant and presented in a well-structured manner. The manuscript is scientifically sound and the experimental design is appropriate to test the hypothesis. The manuscript’s results are reproducible based on the methods section. The data are interpreted appropriately and consistently throughout the manuscript. The conclusions are consistent with the evidence and arguments presented.
My comments and recommendations:
I understand that it is a brief report which has a narrow topic, but it is not clear. The Figures are not easy to interpret and understand. You should add tables or figures with real data, probably into the text or Supplementary Section. The arrows pointing to the same parameter should be painted in a separate color.
You should include details regarding the statistical analysis in Methods and Results section.
The cited references are relevant, they do not include an excessive number of self-citations, but they are mostly old publications (out of the last 5 years). If possible, change them to newer ones.
Author Response
Dear madam/sir,
Thank you for recognizing our work on its scientific integrity and the quality of the work and writing. And thank you for kindly helping us improving the manuscript with your suggestions. We have fully revised the manuscript corresponding to your suggestions one by one. Besides, we also produced new Figures 2-4 each is in high resolution TIFF format besides wider arrows. Modifying/grouping traits’ text by color is challenging for the limited space with so many traits. For the main figures (2-4) we have thus removed the parameters on total ‘root length’ and ‘root area’, and supplied the original Figures with all pamaters in the current Supplementary Figures S1-S3. We also added the Supplementary Table S1 supplying the data set of all traits, and added the statistics subsection as ‘4.4. Statistical analyses’. We added the Conclusions section and the Supplementary Materials section. We shortened the first few paragraphs in the Introduction, extended the key parts in the Results section and Discussions section, and added new literatures accordingly.
Please feel free to let us know if you have any questions and/or more suggestions. We sincerely acknowledge your time and effort.
Thank you.
Shuangxi Zhou and all authors
Author Response File: Author Response.docx
Reviewer 3 Report
Comments and Suggestions for AuthorsDear Authors,
Suggestions for correction are in the attached file.
Kind regards,
Comments for author File: 
Comments.pdf
Author Response
Dear madam/sir,
Thank you for your kind help in improving the manuscript. We have fully revised the manuscript corresponding to your suggestions one by one as follows. Besides, we produced new Figures 2-4, Supplementary Figures S1-S3 and Supplementary Table S1 supplying the data set of all traits. We shortened the first few paragraphs in the Introduction, extended the key parts in the Results section and Discussions section, and added new literatures accordingly. We added the Conclusions section and the Supplementary Materials section. We also deleted 1 literature and added 8 new literatures accordingly across the manuscript.
Please feel free to let us know if you have any questions and/or more suggestions. We sincerely acknowledge your time and effort.
Thank you.
Shuangxi Zhou and all authors
Comment 1: You should point out how the increase in biomass in areas further from the drip line or at greater depths, as evidenced by the PCA, represents the resilience of the almond tree's root system, directly linking vertical and horizontal plasticity to the resource acquisition strategy.
Response 1: Thanks, and we fully agree. Now this key point is clarified in the Abstract section.
Comment 2: In the Introduction, when presenting the hypothesis and the four-year experimental design, the rationale for the temporal (interannual) study of total root production should be reinforced, as this is a critical factor for understanding resilience and for optimizing irrigation and fertilization strategies.
Response 2: Thanks, and we fully agree. Now this key point is clarified in the last paragraph of the Introduction section.
Comment 3: You may have noticed that the use of average scale values ​​and the difficulty in maintaining reliable data during the peak of the day led to "some underestimations" and "more variation than expected." Therefore, it is important to include a justification for the sufficiency of using only one sensor per plot to capture the variability of canopy and water use among trees, especially since the differences between treatments were not statistically significant.
Response 3: Thanks for pointing this out. One sensor was installed for each of the 24 plots (n = 6; 4 treatments; in total 24 sensors). Now this key information is clarified in the '4.3. Sap flow meter installation and observation' section.
Comment 4: Subsection 3.2 (PCA Analysis of Root Traits) details the year-by-year adjustments to root traits (2017, 2018, and 2019), listing the treatments that led to increased biomass, diameter, SRA, and SRL at specific depths and distances. You should include a temporal synthesis after the description of the 2019 results that consolidates the overall change in root allocation pattern over the four treatment years, rather than leaving this integration for the Discussion. For example, highlight whether plasticity (such as the increasing impact of the +W−N treatment) resulted in more consistent resource allocation at specific depths or in zones further from the drip line over time.
Response 4: Thanks, and we fully agree. Now this key point is clarified in subsection 2.3.
Comment 5: Figures 2, 3, and 4 (PCA Analysis) are extremely dense, containing multiple vectors for Biomass, Diameter, SRL, and SRA, categorized by distance (dripline, off-mound, mid-row) and depth (D1, D2, D3). The PCA figure captions should be simplified or supplemented to improve visual and interpretative accessibility. Although the categories D1, D2, D3 and the treatments (T1-T4) are defined in the text and captions, clarity would be enhanced if the figure captions included a concise list of the acronyms for root traces (SRA, SRL) and spatial/depth categories (D1, D2, D3) directly in the graph or in their immediate description, helping the reader decipher the complexity of the vectors without having to consult the Materials and Methods text every time.
Response 5: Thanks, and we fully agree. Now this key point is expanded as the final paragraph of the Results section.
Comment 6: It is important to more explicitly connect the fact that the percentage reduction in water use by the plant was less than the percentage reduction in irrigation applied (indicating improved irrigation use efficiency) with the spatial and morphological adjustments of the roots observed in the PCA. This connection reinforces the idea that root plasticity is the underlying mechanism that allows the plant to maintain water demand and, consequently, yield.
Response 6: Thanks, and we fully agree. Now this key point is clarified in subsection 3.2.
Comment 7: Before introducing suggestions for future studies (such as comparing different Prunus genotypes or using digital technologies), the conclusion should ensure that the authors emphasize that the vertical, horizontal, and temporal dynamics detailed in this study establish an essential baseline of resilience for one of the most common combinations in Australia, and that this is the critical starting point for future comparisons.
Response 7: Thanks, and we fully agree. Now this key point is clarified in subsection 3.2.
Author Response File: Author Response.docx
