Optimizing Peat and Wood Fiber Blends: Impacts of Liming and Fertilization on Growth of Petunia (Petunia x hybrida Vilm.) and Basil (Ocimum basilicum L.)
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsSummary
The manuscript is well written. The methods are detailed but lack a thorough description of the plant material used. The results are clear and well presented, but the authors must provide figures of higher quality. The conclusions are schematic and precise, aligning well with the aim of the work.
Title
Please, insert the scientific name of the species employed for the trial
Abstract
The abstract is very concise and precise, thoroughly stating the aim of your work. I suggest adding one or two lines at the beginning as a "background" to highlight the relevance of your work in a modern context. Additionally, it would be beneficial to represent the units of measure without the ratio symbol, e.g., g L-1 (in the entire manuscript).
Introduction
The introduction adequately conveys the aim of the work. However, it would be beneficial to add references related to the different Basil and Petunia species, focusing on their various chemotypes and suitable crop selection for different purposes. Here are some works that I highly recommend citing in your valuable manuscript: (https://doi.org/10.3390/agronomy14010224; https://doi.org/10.1590/1678-4685-GMB-2022-0114)
Materials and Methods
The experimental conditions are well described. However, I recommend adding a new subsection named "Plant Material," detailing the genotypes used. You should specify the origin, the provider, the growing technique, and the phenological phase corresponding to the start of the trial, among other details.
Results
Results are clearly presented. Nevertheless, Figures must be replaced with Pictures having higher quality.
Discussion
The authors thoroughly discussed the reasons behind the results, supporting their arguments with adequate bibliographical references.
Author Response
Dear Reviewer 1:
Thank you for your positive feedback and insightful comments which helped to improve our manuscript.
Summary
The manuscript is well written. The methods are detailed but lack a thorough description of the plant material used. The results are clear and well presented, but the authors must provide figures of higher quality. The conclusions are schematic and precise, aligning well with the aim of the work.
Thank you for this comment. We incorporated your suggestions into the new version of the manuscript.
Title
Please, insert the scientific name of the species employed for the trial
Scientific names are included in the title.
Abstract
The abstract is very concise and precise, thoroughly stating the aim of your work. I suggest adding one or two lines at the beginning as a "background" to highlight the relevance of your work in a modern context. Additionally, it would be beneficial to represent the units of measure without the ratio symbol, e.g., g L-1 (in the entire manuscript).
Thank you for this comment. Background information is added and units are changed accordingly.
Introduction
The introduction adequately conveys the aim of the work. However, it would be beneficial to add references related to the different Basil and Petunia species, focusing on their various chemotypes and suitable crop selection for different purposes. Here are some works that I highly recommend citing in your valuable manuscript: (https://doi.org/10.3390/agronomy14010224; https://doi.org/10.1590/1678-4685-GMB-2022-0114)
Thank you for your suggestions, however we think that introducing these references would only marginally improve this manuscript. While the suggested publications show the description physiological and morphological characteristics of various cultivars, they do not show how different cultivars react to different growing conditions, especially growing media.
However, we expanded the introduction section to justify the selection of these two species as model plants for our research citing: Nelson, P.; Greenhouse operation and management. 7th ed. 2012.
Materials and Methods
The experimental conditions are well described. However, I recommend adding a new subsection named "Plant Material," detailing the genotypes used. You should specify the origin, the provider, the growing technique, and the phenological phase corresponding to the start of the trial, among other details.
Thank you for your suggestion, however we think that including a section about plant material will not improve the readability of the manuscript, as this work is focused more on growing conditions. Details about genotypes of petunia and basil plants are already provided in Materials and Methods section. Growing technique and phenological stages are also presented. However, the origin of the seeds was added into the manuscript together with more details about phenological stage of the plants at the end of experiment.
Results
Results are clearly presented. Nevertheless, Figures must be replaced with Pictures having higher quality.
The resolution of the figures is now improved.
Discussion
The authors thoroughly discussed the reasons behind the results, supporting their arguments with adequate bibliographical references.
Thank you for your comment.
Reviewer 2 Report
Comments and Suggestions for AuthorsThis work is important because it promotes the search for sustainable and eco-friendly substrates, as they come from waste material. Horticulture urgently requires this type of substrates to reduce the excessive use of products that promote the aridity of ecosystems. From my point of view, the work is generally good, but I consider that the authors should revise and perhaps include some data, as I kindly indicate below.
Introduction
- It is suggested that the authors indicate why they used two very different cultures (petunia and basil) in their study, what was the purpose of choosing them, and why in the second experiment they used only petunia.
- In their first hypothesis, the authors mention: "(i) wood fiber and peat blends provide comparable root zone conditions to peat substrates", but they do not show any data or results evaluated on the root or anything about it.
Materials and Methods
- It is recommended that the authors submit physicochemical data on the substrates used.
Results
- Lines 204-205. Why do the authors put a conclusion there?
- It would be good if the authors could present data on petunia flowering.
Discussion
- Lines 295-302. It would be advisable for the authors to include citations in this section of the discussion and to mention data, if available, for the crops they tested.
- Lines 311-314. The idea of the discussion is not clear, is it in relation to the work of other authors?
Figures
- Each figure should indicate the type of statistical analysis, means employed, significance of bars, etc.
- Figures 4 and 5. It is suggested to change "g/plant" to "g plant-1".
- Figures 3, 5, 6 and in the other necessary ones: It is suggested to change "g/l" to "g l-1".
- The same is recommended for the other units mentioned, e.g., under "Multimix/L" change to "Multimix L-1".
- In Figure 7, what does "pH pt" mean? Identify it in the figure caption.
- The captions and abbreviations in Figure 8, subfigures A-F are too small. It is advised to increase the font size.
Author Response
Dear Reviewer 2:
Thank you for your positive feedback and insightful comments which helped to improve our manuscript.
Introduction
-It is suggested that the authors indicate why they used two very different cultures (petunia and basil) in their study, what was the purpose of choosing them, and why in the second experiment they used only petunia.
-In their first hypothesis, the authors mention: "(i) wood fiber and peat blends provide comparable root zone conditions to peat substrates", but they do not show any data or results evaluated on the root or anything about it.
Thank you for your comment. We added the sentence describing the reason why we choose petunia and basil as a model species.
The choice of using only petunia in the second experiment was due to the space and workforce limitations.
We apologize for the confusion. “Root zone” is now exchanged with “growing conditions” the hypothesis to be more concise and better represent the results of this study.
Materials and Methods
-It is recommended that the authors submit physicochemical data on the substrates used.
Thank you for your suggestion. However, at the time when the experiment was conducted, we were not able to analyze the physicochemical properties of substrates and therefore data is not available.
Results
-Lines 204-205. Why do the authors put a conclusion there?
Thank you that you pick this unfortunate use of the word “concluded”. We changed “concluded” to “observed”.
-It would be good if the authors could present data on petunia flowering.
Unfortunately, data on petunia flowering date was not recorded, because highly unified flowering observed across the treatments.
Discussion
-Lines 295-302. It would be advisable for the authors to include citations in this section of the discussion and to mention data, if available, for the crops they tested.
Thank you for this suggestion. We included the following references in this section and highlighted the similarities between our and Jackson’s work:
Jackson, B.E., R.D. Wright, and N. Gruda, Container medium pH in a pine tree substrate amended with peatmoss and dolomitic limestone affects plant growth. HortScience, 2009. 44(7): p. 1983-1987.
Nelson, P.; Greenhouse operation and management. 7th ed. 2012.
-Lines 311-314. The idea of the discussion is not clear, is it in relation to the work of other authors?
This section was reorganized to make it clearer and more concise.
Figures
-Each figure should indicate the type of statistical analysis, means employed, significance of bars, etc.
Thank you for this suggestion. The following text was added to each figure caption where applicable and contains now necessary information about employed statistical parameters: “Black dots represent means; bars represent 95% CI of the mean. Means are different (p<0.05) when CI are not overlapping.”
-Figures 4 and 5. It is suggested to change "g/plant" to "g plant-1".
Figures are changed.
-Figures 3, 5, 6 and in the other necessary ones: It is suggested to change "g/l" to "g l-1".
Figures are changed.
-The same is recommended for the other units mentioned, e.g., under "Multimix/L" change to "Multimix L-1".
Units are changed.
-In Figure 7, what does "pH pt" mean? Identify it in the figure caption.
pH pt is clarified in the figure caption.
-The captions and abbreviations in Figure 8, subfigures A-F are too small. It is advised to increase the font size.
The resolution of Figure 8, and the other figures as well, is now improved.
Reviewer 3 Report
Comments and Suggestions for AuthorsThis article examines the effects of different material ratios in soilless culture substrates on plant growth. Overall, while the experiment tested numerous treatment combinations and compared two plant species, the scientific conclusions and their practical significance remain unclear.
A key issue is that although the authors pointed out the key role of substrate pH on plant growth (in the Introduction and Discussion), there are problems with the method of determining substrate pH in the experiment. First, the pH determination methods in Experiments 1 and 2 are different. The un-standardized extraction methods make it difficult to discuss the experimental results together. Second, the substrate pH in Experiment 1 was determined by the pour-through method after ("during" in the manuscript, not clear what it refers to) the plant culture was terminated. This determination method does not reflect the chemical environment of the rhizosphere during plant growth. In Experiment 2, the authors mentioned that the higher pH of the high-wood fiber treatments was caused by the organic acids generated during the wood treatment being leached out by irrigation water. This explanation is not convincing because of the lack of relevant data (such as the pH of the leaching water in the initial stage of the experiment).
Another key issue is that the experimental period was short (about 5 weeks), and the long-term changes in the substrate were not considered. Usually, soilless culture substrates are recycled for many crop cycles, and the degradation of organic matter in them can affect their physiochemical properties and nutrient availability over time. Therefore, their sustainability remains to be explored. Thus, the claim in the article suggesting wood fiber/peat blends as sustainable horticultural substrates (L339-340) is inaccurate without addressing the limitations of this short-term study.
In addition, the experimental design is not clearly explained regarding the necessity of treatment combinations to verify the experimental hypothesis. For example, why were petunia and basil chosen for the experiment? Additionally, given that "The liming requirement depends on the initial pH of the substrate, the desired target pH, and the buffering capacity of the substrate material" (L35-36), details on how lime application rates were calculated and determined are absent.
Author Response
Dear Reviewer 3:
Thank you for your positive feedback and insightful comments which helped to improve our manuscript.
This article examines the effects of different material ratios in soilless culture substrates on plant growth. Overall, while the experiment tested numerous treatment combinations and compared two plant species, the scientific conclusions and their practical significance remain unclear.
A key issue is that although the authors pointed out the key role of substrate pH on plant growth (in the Introduction and Discussion), there are problems with the method of determining substrate pH in the experiment. First, the pH determination methods in Experiments 1 and 2 are different. The un-standardized extraction methods make it difficult to discuss the experimental results together. Second, the substrate pH in Experiment 1 was determined by the pour-through method after ("during" in the manuscript, not clear what it refers to) the plant culture was terminated. This determination method does not reflect the chemical environment of the rhizosphere during plant growth.
Thank you for the comment. We apologize for the confusion. The methodology of pour through method was the same in both experiments and was based on Wright, R.D., The pour-through nutrient extraction procedure. HortScience, 1986. 21(2): p. 227-229. Therefore, description of the method was changed to be more concise.
In Experiment 2, the authors mentioned that the higher pH of the high-wood fiber treatments was caused by the organic acids generated during the wood treatment being leached out by irrigation water. This explanation is not convincing because of the lack of relevant data (such as the pH of the leaching water in the initial stage of the experiment).
Thank you for this comment. We adapted the text accordingly and added the reference shedding light on the possible explanation of the discussed phenomenon.
Another key issue is that the experimental period was short (about 5 weeks), and the long-term changes in the substrate were not considered. Usually, soilless culture substrates are recycled for many crop cycles, and the degradation of organic matter in them can affect their physiochemical properties and nutrient availability over time. Therefore, their sustainability remains to be explored. Thus, the claim in the article suggesting wood fiber/peat blends as sustainable horticultural substrates (L339-340) is inaccurate without addressing the limitations of this short-term study.
Thank you. We incorporated your comment as a part of the discussion.
In addition, the experimental design is not clearly explained regarding the necessity of treatment combinations to verify the experimental hypothesis. For example, why were petunia and basil chosen for the experiment? Additionally, given that "The liming requirement depends on the initial pH of the substrate, the desired target pH, and the buffering capacity of the substrate material" (L35-36), details on how lime application rates were calculated and determined are absent.
Thank you for your comment. The choice of the species was also highlighted by another reviewer and this issue is clarified in the text. The liming application doses were gradually upgraded and downgraded from the commercial standard which is 4g of lime per liter of substrate. This is now clarified in the text.
Reviewer 4 Report
Comments and Suggestions for AuthorsDear Authors,
Your manuscript seems to me very interesting, mainly because it can have a strong practical impact. I have only some minor remarks, which should improve the quality of your manuscript:
Introduction
It is very well written and easy to read. The number of cited sources here and in discussion is relatively low, but after my meaning sufficient.
Materials and methods
I have only one comment - line 82: mention only the size of the pots (10 cm) is not sufficient. It is not sure if 10 cm is the width or length or depth. You should even mention the volume of pots and the volume (or weight) of added substrates per pot.
Results:
Generally: I recommend highlight more the significancy of your results in the text. It means to describe further, among which exact treatments the significancy was found. The statement, e.g., "significant statistical differences were observed for plant height, weight and diameter" is not sufficient. You should specify, among which treatments and which parameters you found the difference.
Figure 1C - The plant diameters around 25 cm seems to me too big. Please specify in the methodology, how the diameter was measured.
Figure 4A, 4B: you should add into the figure regression equation with regression coefficient R2 as well as correlation (maybe Pearson) coefficient r to show the strength of the relationship.
Figure 8F: the same - you should add into the figure regression equation with regression coefficient R2.
Figure 9B: Here is the linear equation, but the correlation and regression coefficients are missing.
It would be interesting to compare all data you have from press and pour-through method form both experiments and in case of good correlation r>0.900, you can suggest the linear equation for the recalculation of press results to pour-through and vice versa. It can be even one of the conclusions of your manuscript.
Discussion
It seems that wood fiber shows some negative effect on plant growth. It is partially explained in discussion. Furthermore, I assume that wood fiber is containing some growth inhibitors, e.g., phenolic acids. You can consider this and other possible reasons in discussion to make it more complete.
Lines 318-320: You are writing about "steam-explosion" of wood fiber. Can you please describe this process further for not well-informed reader?
After considering my suggestions I will be glad to recommend publish your manuscript in Horticulture journal.
Yours sincerely
Reviewer
Author Response
Dear Reviewer 4:
Thank you for your positive feedback and insightful comments which helped to improve our manuscript.
Materials and methods
I have only one comment - line 82: mention only the size of the pots (10 cm) is not sufficient. It is not sure if 10 cm is the width or length or depth. You should even mention the volume of pots and the volume (or weight) of added substrates per pot.
Thank you for your comment. We added dimensions and volume of the pots in the Materials and methods section.
Results:
Generally: I recommend highlight more the significancy of your results in the text. It means to describe further, among which exact treatments the significancy was found. The statement, e.g., "significant statistical differences were observed for plant height, weight and diameter" is not sufficient. You should specify, among which treatments and which parameters you found the difference.
Thank you for this comment. We have not focused much on highlighting the significance because of rather high variability in the plant material. However, the idea of application of confidence intervals as an indicator of statistical significance can, in our opinion, give clearer overview of the results. Rather than focusing on finding p-values, which are lower than 5%, we looked more into describing the trends in the data. Nevertheless, the differences between treatments were in general significant and classical analysis of variance are provided in the supplementary tables.
Figure 1C - The plant diameters around 25 cm seems to me too big. Please specify in the methodology, how the diameter was measured.
Thank you for picking this up. We specified the methodology of measurement in the Materials and Methods section.
Figure 4A, 4B: you should add into the figure regression equation with regression coefficient R2 as well as correlation (maybe Pearson) coefficient r to show the strength of the relationship.
Thank you for this suggestion. Both regression equation and Pearson correlation coefficients are added to the figure/figure caption.
Figure 8F: the same - you should add into the figure regression equation with regression coefficient R2.
Thank you for this suggestion. Both regression equation and Pearson correlation coefficients are added to the figure/figure caption.
Figure 9B: Here is the linear equation, but the correlation and regression coefficients are missing.
Thank you for this suggestion. Both regression equation and Pearson correlation coefficients are added to the figure/figure caption.
It would be interesting to compare all data you have from press and pour-through method form both experiments and in case of good correlation r>0.900, you can suggest the linear equation for the recalculation of press results to pour-through and vice versa. It can be even one of the conclusions of your manuscript.
Unfortunately, Experiment 1 did not include press method, therefore, this comparison is not possible.
Round 2
Reviewer 3 Report
Comments and Suggestions for AuthorsThank you for addressing part of my concern regarding the pH determination methods. However, my primary concern about the timing of the pH measurement in Experiment 1 remains unresolved. Measuring pH after the termination of plant culture may not accurately reflect the rhizosphere environment during plant growth, which is critical for interpreting the results. Please clarify or provide additional justification for this methodology.
Author Response
Comment: "Thank you for addressing part of my concern regarding the pH determination methods. However, my primary concern about the timing of the pH measurement in Experiment 1 remains unresolved. Measuring pH after the termination of plant culture may not accurately reflect the rhizosphere environment during plant growth, which is critical for interpreting the results. Please clarify or provide additional justification for this methodology."
Authors response: Dear Reviewer. Thank you for your comment. Indeed, the statement in the Materials and Methods can be misleading. The pH measurements were conducted on pots with living plants during the last day of experiment. The termination of the plants was done right after the measurements. We changed the previous description of the experiment:
"Measurements were conducted during the last day of experiment before termination of the plants. Each pot was extracted one hour after irrigation using the pour-through method using 100 ml of water and leach-ate was tested immediately after collection"
We hope that with this amendments the manuscript will now be aceptable for publication.
Sincerely yours
Author Response File: 
Author Response.pdf
