Evaluation of Phosphate-Solubilizing Bacteria (PSB) on Phosphorus Availability in Agricultural Soils and the Growth of Wheat (Triticum aestivum L.)
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsEven it is a very simple experiment, the work is worthy and better presentation and analysis are encouraged. The main objections and suggestions are the following:
-The use of PSB can hardly be considered as an organic fertilization strategy
-The introduction is a little superficial and reiterative
-More information on the analytical methods should be given, particularly the P availability test
-On the contrary, the rest of the Material and Methods section should be simplified and condensed. There is a lot of non-essential detail (see 2.8, for instance)
-Why inoculation rates are not indicated as absolute populations instead of percentages of the original inoculum?
-Given the small size of the plants and low number of treatments, a much bigger experiment (more replicates, more plants) could have been used
-Section 3.1 is far too long and detailed
-Data sorted according results instead of according treatment (0->15%) is very unusual. All results, using the treatment as main variable, should be presented in a single table for each sampling date.
-Results are quite hard to understand. For instance, in day 29 15% I gives much less height and leaf area than the control but more than twice biomass weight.
-Results in fresh and dry form are not consistent, suggesting and effect of the treatments on the water absorption of the plant, that is not discussed.
-Many results are commented on the text as positive without existing statistical differences (see Table 11, for instance)
-The correlation analysis Soil P/treatments is far too simple
Author Response
REVIEWER 1:
Even it is a very simple experiment, the work is worthy and better presentation and analysis are encouraged. The main objections and suggestions are the following:
- The use of PSB can hardly be considered as an organic fertilization strategy
Answer: We appreciate your observation and fully understand the importance of accurately classifying the use of PSB. In the context of our research, PSB are not organic fertilizers per se, but rather biological agents that enhance phosphorus availability in the soil by solubilizing insoluble phosphates. This mechanism reduces reliance on chemical fertilizers, thereby promoting more sustainable agricultural practices. Consequently, we have revised the wording in the introduction and improved the title in accordance with the suggested observation. Additionally, these corrections have been applied throughout the entire document.
- The introduction is a little superficial and reiterative
Answer: We have reviewed, restructured, and enhanced the introduction to minimize redundancies, delve deeper into the theoretical and practical context of using PSB, and emphasize their relevance as an alternative for promoting sustainable agricultural practices.
- More information on the analytical methods should be given, particularly the P availability test
Answer: We have expanded the description of the analytical methods used for parameter measurement, incorporating it into the corresponding section.
- On the contrary, the rest of the Material and Methods section should be simplified and condensed. There is a lot of non-essential detail (see 2.8, for instance)
Answer: We have revised the Materials and Methods section to simplify it and focus on the most relevant aspects, condensing sections that contained non-essential details while retaining only the information necessary to replicate the study.
- Why inoculation rates are not indicated as absolute populations instead of percentages of the original inoculum?
Answer: In this study, inoculation rates were expressed as percentages of the original inoculum due to their practicality and consistency in preparing treatments. This approach standardizes the applied volume regardless of slight variations in inoculum concentration, ensuring the reproducibility of results. Furthermore, since the percentages were calculated from an inoculum previously adjusted to 1 on the McFarland scale, the initial bacterial densities were ensured to be equivalent across treatments.
- Given the small size of the plants and low number of treatments, a much bigger experiment (more replicates, more plants) could have been used
Answer: We acknowledge that a higher number of replicates and plants could enhance the statistical robustness of the study and allow for more detailed analyses. However, the experimental conditions were constrained by logistical factors, including available space and allocated resources for cultivating and analyzing wheat under controlled conditions. Despite these limitations, the experimental design was carefully structured to ensure the representativeness of treatments and enable meaningful comparisons. In future research, we plan to increase the number of replicates and treatments, which will allow for a more precise evaluation of the impact of PSB under a broader range of conditions and scales.
- Section 3.1 is far too long and detailed
Answer: We have reviewed and refined Section 3.1 to focus on the key aspects of PSB isolation and identification, removing secondary operational details to enhance clarity and conciseness.
- Data sorted according results instead of according treatment (0->15%) is very unusual. All results, using the treatment as main variable, should be presented in a single table for each sampling date.
Answer: We have reorganized the data to present it according to treatment levels (0%, 5%, 10%, 15%) as the primary variable for each sampling date.
- Results are quite hard to understand. For instance, in day 29 15% I gives much less height and leaf area than the control but more than twice biomass weight.
Answer: We have revised the manuscript to include a more detailed explanation of these results in the discussion, highlighting potential reasons for these discrepancies and linking them to the mechanisms of action of the bacterial inoculum.
- Results in fresh and dry form are not consistent, suggesting and effect of the treatments on the water absorption of the plant, that is not discussed.
Answer: In the discussion section, we have included an analysis linking these results to the plants' water retention capacity and the potential physiological implications of treatments with different BSP doses.
- Many results are commented on the text as positive without existing statistical differences (see Table 11, for instance)
Answer: We have carefully reviewed the data and found a statistically significant difference (p < 0.0255) between the treatments, particularly when comparing the 10% inoculum treatment with the others. Therefore, the text has been adjusted to more accurately reflect the statistical results and avoid ambiguous interpretations.
- The correlation analysis Soil P/treatments is far too simple
Answer: We have expanded this section by incorporating a more detailed discussion of the results obtained. In addition to the Spearman correlation coefficient, an ANOVA was conducted to assess significant differences in phosphorus availability between treatments, followed by a post hoc Tukey test to identify which treatments showed significant differences.
Reviewer 2 Report
Comments and Suggestions for Authors1)Table 1: How did you measure pH? Please specify the standard used.
2)Table 1: The analysis of available phosphorus (P) indicates a value of 33.67 ± 0.1. Please round the numbers correctly after the decimal point.
3)Tables 6 to 12: Find the relationship between the PSB inoculum dose and the average fresh biomass of roots (g), as well as the average diameter of stems (mm).
4)Redo the conclusion based on the observations from question 3.
Author Response
REVIEWER 2:
1) Table 1: How did you measure pH? Please specify the standard use
Answer: We have added details about the procedure for measuring soil pH, including the standard used. This information is now incorporated into the relevant section of the manuscript.
2) Table 1: The analysis of available phosphorus (P) indicates a value of 33.67 ± 0.1. Please round the numbers correctly after the decimal point.
Answer: In this case, we have decided to maintain two decimal places in the reported value (33.67 ± 0.1), as they reflect the precision of the analytical method used, ensuring consistent results.
3) Tables 6 to 12: Find the relationship between the PSB inoculum dose and the average fresh biomass of roots (g), as well as the average diameter of stems (mm).
Answer: We have reviewed the relationships between the PSB inoculation dose and the parameters of fresh root biomass and average stem diameter.
4) Redo the conclusion based on the observations from question 3.
Answer: The conclusion has been rewritten based on the previous observation.
Reviewer 3 Report
Comments and Suggestions for Authors1. the reference 10, 16 and 33, what the style is ? paper, book or other?
2. in conclusion, the data needs contrasted with CK, and show out the rate and significant or not.
3. in the results, all the data has not compared indication, the changed rate was missing and needed get back for a better understanding.
4. in table 20, the significant analysis in the pearson correlation was so needed.
5. the figure 7, can you give a picture in front, with a clean and clear plant as figure 6.
6. the mean data, how many repeats, and the SD or SE, should show in the table.
7. in table 14, the leaf area in 15% and No, 7.97 compared with 12.14, was not significant ? please confirm.
8. in figure 4, the data has the repeats or not, the analysis need insert.
9. the whole paper needs simplied and focus on the main idea.
Comments on the Quality of English Languageneeds improved
Author Response
REVIEWER 3:
- the reference 10, 16 and 33, what the style is? paper, book or other?
Answer:We appreciate your observation and have reviewed the mentioned references to ensure they are properly categorized. Below, we specify the source type for each one:
- Reference 10: Technical report
- Reference 16: Technical report
- Reference 33: Thesis
In the revised manuscript, we have adjusted the format of these references to comply with the citation guidelines set by the journal.
- in conclusion, the data needs contrasted with CK, and show out the rate and significant or no
Answer: The conclusion has been revised to include the rate of change, as requested by the reviewer.
- in the results, all the data has not compared indication, the changed rate was missing and needed get back for a better understanding.
Answer: The rate of change has been added to the results for better comparison.
- in table 20, the significant analysis in the pearson correlation was so neede
Answer: We have reviewed this point and calculated the significance (p) values associated with each correlation coefficient. The results have been added to the table to clarify which relationships are statistically significant (p < 0.05) and which are not.
- the figure 7, can you give a picture in front, with a clean and clear plant as figure
Answer: Unfortunately, we do not have a higher resolution image due to limitations in the conditions under which the experiment was conducted. However, we believe that the current image is representative and serves its purpose.
- the mean data, how many repeats, and the SD or SE, should show in the table.
Answer: The average values presented in the results include three independent replicates for each treatment. The corresponding standard error (SE) for each average is shown in the table as: value ± SE.
- in table 14, the leaf area in 15% and No, 7.97 compared with 12.14, was not significant? please confirm.
Answer: After reviewing the data and statistical analysis, we confirm that Fisher's LSD test assigns the same letter to the leaf area values of the 15% treatment (7.97 cm²) and the control treatment (12.14 cm²). This indicates that the means are not significantly different (p > 0.05). We have adjusted the text to reflect this lack of significance and to avoid incorrect interpretations in the manuscript.
- in figure 4, the data has the repeats or not, the analysis need insert.
Answer: We have decided to remove Figure 4 to simplify the manuscript, as the data it presents is already described earlier in Figure 3.
- the whole paper needs simplied and focus on the main idea.
Answer: We have reviewed and restructured the entire manuscript to achieve greater clarity and focus.
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsThe article, even if still far too long, has been very much improved and the questions adecuately addressed.
The tables are disarrayed.
Author Response
The tables have been reorganized to show the work in a more direct way, highlighting the research objectives.
Reviewer 2 Report
Comments and Suggestions for Authorsit's a good work
Author Response
Thank you for your comments, dear reviewer.
Reviewer 3 Report
Comments and Suggestions for Authors1. the final conclusion needs make at the end of abstract;
2. "significant differences" means increase or decrease, should clear;
3. table 6, improved for a better vision;
4. in the results, all data should tell us increase or decrease significantly or not, please improved.
5. the conclusion needs combined all the obvious results, and then give us mainly conclusion about the whole research.
Author Response
- The final conclusion has been added at the end of the abstract.
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In the manuscript, "significant differences" refer to the results of the statistical tests applied, particularly Fisher's LSD test, which identifies specific significant differences between treatments and the control.
To clarify whether these differences represent increases or decreases, we calculated the rate of change for each parameter relative to the control. This additional analysis is included in the results and provides a clear understanding of the direction and magnitude of change for each treatment. For example, the optimal dose of 10% PSB resulted in significant increases in plant height (40.29%), leaf area (44.23%), and biomass parameters (800%-1200%) compared to the control.
- Table 6 and Table 5 show a compilation of the Fisher tests applied to each parameter in the evaluation of the growth and development of wheat seedlings by different doses of BSP inoculum and without inoculum. In the first column, the different doses are shown. In the following columns, the parameters evaluated in the growth of wheat seedlings are shown, as well as their respective means ± standard error. The letters below each mean ± SE indicate the significant differences between each dose. For example, in plant height, it is observed that the 5% and 10% doses have the same letter, which indicates that they are not significantly different. On the contrary, when each dose has a different letter, it means that they have significant differences.
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The Fisher's LSD test was applied to identify specific significant differences between the treatments (inoculum doses) and the control. While this test highlights differences within groups, it does not inherently describe whether a parameter increases or decreases significantly.
To address this, we calculated the rate of change relative to the control for each parameter after determining the optimal dose, which was 10% PSB. These rates of change, presented in the results section, clearly indicate whether each parameter increased or decreased compared to the control, providing a comprehensive understanding of the treatment effects.
- The conclusion has been reworked with the comments made by the reviewer.
