Growth Curve and Nutrient Accumulation in Lettuce for Seed Production Under Organic System

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

View letter

1. Line 20 "N accumulation of 1527.7 mg per plant at 800 kg ha-1 dose" contradicts Line 550 results section "N accumulation of 1743.1 mg per plant at 320 kg ha-1 dose". Verify data accuracy (e.g., confirm whether N accumulation at 800 kg ha-1 dose should be higher).
2. The sampling description contains logical inconsistencies. Line 91 states "except for transplanting day (0 DAT) when 120 seedlings were sampled, each sampling point was conducted with 3 replicates, 1 plant per mu", which is confusing as "1 plant per mu" appears unreasonable.
3. Table unit labeling is misaligned. In Line 96 Table 1, the unit "mg dm⁻³" for "P res" is not on the same line. Adjust table width and ensure proper allocation.
4. The fertilization timing in the methods section is unclear. Line 101 "each plant was fertilized with castor bean cake and potassium sulfate during planting" does not specify the timing (e.g., whether it was a one-time application at transplanting). Supplement with fertilization time points (e.g., "applied at transplanting") and frequency (e.g., "applied in stages") to enhance methodological reproducibility.
5. Statistical model formula contains symbol errors. In Line 160 "formula y=a/[1+e-k(x-xc)]", "xc" should be subscripted as "x₀".
6. Figure numbering in the results section is inconsistent. Line 187 cites Figure 3, while Line 201 cites Figure 2, but the main text starts with Figure 2, indicating numbering gaps. Adjust figure order to ensure cited numbers match actual figures.
7. Decimal precision is inconsistent across tables: Line 96 Table 1, Line 118 Table 2, and Line 126 Table 3. Standardize data precision.
8. Key information is missing in figure/table titles. Line 118 Table 2 "Dry matter accumulation" lacks phosphorus dose labeling, and Line 126 Table 3 omits cultivar names.
9. Insufficient literature linkage in the discussion. Line 428 "Nascimento[5] studied seed production in different lettuce genotypes" does not explain how its conclusions relate to this study (e.g., maturity period comparison).
10. Line 542 conclusions fail to report seed yield or quality data (e.g., thousand-seed weight, germination rate), mentioning only nutrient accumulation. Supplement with seed yield results (e.g., "seed yield increased by X% at 800 kg/ha dose") to enhance conclusion completeness.
11. Line 579 shows inconsistent author abbreviation in reference [9].

Comments for author File: Comments.pdf

Author Response

Editor

We reduced the number of self-citations (we removed 3 citations).

Revisor 1

1. The results presented are correct, i.e. the accumulation of N in the 800 kg ha^-1 dose of P₂O₅ (1527.7 mg per plant) was lower than the accumulation in the 320 kg ha^-1 dose of P₂O₅ (1743.1 mg per plant). Only for N accumulation the lowest dose resulted in higher accumulation than the highest dose. The results were reviewed and this information was confirmed, as the N content of the lowest dose was higher than that of the highest dose.
2. The text is correct. Without considering the day of transplanting (0 DAT), another 7 samples were taken with 3 plants in each sample, each plant being considered a repetition, totaling 21 plants sampled throughout the cycle. Care was taken to collect only normal plants. In our experience, for this type of work, 3 repetitions in each sample is enough, except on the day of transplanting when the plants are still very small and don't have enough dry mass to take samples (a minimum of 1g of dry matter to carry out the analysis). This was the same methodology used by other authors who evaluated lettuce for seed production.
3. It has been corrected as requested by the reviewer.
4. Minor changes have been made to the text to make it clear when fertilizing before planting and when top dressing were performed.
5. It has been corrected as requested by the reviewer.
6. It has been corrected as requested by the reviewer.
7. It has been corrected as requested by the reviewer.
8. We didn't make any changes because we couldn't understand what the reviewer meant by “Dry matter accumulation in Table 2” and “cultivar names” in Table 3.
9. It has been corrected as requested by the reviewer.
10. This work did not discuss the production and quality of the seeds produced. Several evaluations were made of production, germination, vigor, nutrient content and extraction in the seeds, including comparisons with an additional treatment with inorganic fertilizers. However, these results will be shown in another paper (there are 4 more extensive tables with results, which would make the paper too long). In addition, the aim of this work was to obtain and discuss the absorption of nutrients by the lettuce plant for seed producion in an organic system, assessing the plant's nutritional requirements at each stage throughout the cycle.
11. It has been corrected as requested by the reviewer.

Reviewer 2 Report

Comments and Suggestions for Authors

General comments:
The manuscript titled "Growth Curve and Nutrient Accumulation in Lettuce for Seed Production under Organic System" presents a well-designed study investigating the effects of phosphorus doses on nutrient dynamics and growth in lettuce cultivated for seed production under organic conditions. The research addresses a relevant gap in the literature, particularly concerning organic seed production systems. The methodology is robust, and the results are clearly presented. However, some aspects require clarification or improvement to enhance the manuscript's impact and readability.

Special comments：

1. Introduction

The introduction could better emphasize the specific hypotheses or research questions guiding the study. Highlight the practical implications of the study for organic lettuce seed producers.

 

2. Materials and Methods

Clarify the rationale for selecting the two phosphorus doses (320 and 800 kg ha⁻¹). Are these based on preliminary studies or literature?

 

Simplify the description of soil correction and fertilization protocols to avoid redundancy

 

Statistical Analysis: While the sigmoidal model is well-applied, additional statistical validation (e.g., ANOVA or post-hoc tests) would strengthen the comparison between phosphorus doses.

 

3. Results:

Provide p-values or confidence intervals for the sigmoidal model parameters to underscore their significance.

 

4. Discussion :

The manuscript should acknowledge potential limitations, such as the single-cultivar focus or the specific climatic conditions of the study site.

 

Expand on why the 320 kg ha⁻¹ dose resulted in higher nitrogen accumulation despite lower phosphorus input.

 

Comments on the Quality of English Language

Some sections, particularly the methods, are overly detailed and could be streamlined for better readability.

Author Response

Revisor 2

1. Introduction: It has been corrected as requested by the reviewer.

 

2. Materials and Methods

- As mentioned in the text, two doses were chosen, the first (320 kg ha^-1 of P₂O₅) is the dose recommended for lettuce production for leaf consumption in the official fertilization bulletin for the state of São Paulo, Brazil (Trani et al., 2022), and the second dose (800 kg ha^-1 of P₂O₅) was the best dose reported for seed production in previously published work (Kano, 2006; Kano et al., 2012).

- Description of soil correction and fertilization: It has been corrections as requested by the reviewer.

- Statistical Analysis: It has been corrected as requested by the reviewer.

 

3. Results

- p-values or confidence intervals: It has been corrected as requested by the reviewer.

 

4. Discussion

- “Potential limitations”: It has been corrected as requested by the reviewer.

- N accumulation: The results presented are correct, i.e. the accumulation of N in the 800 kg ha^-1 dose of P₂O₅ (1527.7 mg per plant) was lower than the accumulation in the 320 kg ha^-1 dose of P₂O₅ (1743.1 mg per plant). Only for N accumulation was the lowest dose higher than the highest dose. The results were reviewed and this information was confirmed, as the N content of the lowest dose was higher than that of the highest dose.

Reviewer 3 Report

Comments and Suggestions for Authors

Please see the attachment.

Comments for author File: Comments.pdf

Author Response

Revisor 3

- Regarding the importance of climate (temperature and photoperiod) we have added a paragraph in the “Discussion” of the results not in the “Introduction”, because we think that is better in the “Discussion”.

- Materials and Methods: It has been corrected as requested by the reviewer.

- Results: the paper already has a large number of figures (11 figures, some with 2 to 4 different graphs) and we felt that putting the data in a table would make the work too long and duplicate results. With the equations presented in the figures, it is possible for any reader to estimate the value of any data they want to see. This is why we prefer not to include new numerical tables in the results.

- Conclusion: If the research had been carried out in the conventional system, it would have been possible to make fertigation recommendations based on the results of the daily accumulation of nutrients. However, in the organic system, the fertilizers used are not ready to release nutrients, which makes it difficult to make a single recommendation. With the results obtained, the grower (or company) can make adjustments to the amount of nutrients and the times when they are applied. However, this recommendation will vary according to the source/ fertilizer used, climatic conditions and other factors. Fertilization recommendations in the organic system are not so easy to make. Research such as this can help producers and companies to improve nutritional management, but this work alone is not enough to make a valid recommendation for different situations.

 

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

View letter

1. Line 12 The content of the abstract can be more concise to avoid repetitive information. For example, the dosage information of phosphorus is mentioned twice, which is slightly redundant. It is recommended to highlight the research purpose, main results, and conclusions, while avoiding excessive descriptive details.
2. Line 27 The introduction can delve deeper into the importance of organic seed production and the current challenges faced. A more specific elaboration on the role of organic seeds in sustainable agriculture and the practical significance of the research is needed.
3. Line 171 The description of statistical analysis methods is overly simplistic. In addition to nonlinear regression, were analyses of variance (ANOVA) or other statistical tests conducted? Please specify the statistical methods used to compare differences between treatment groups, as well as the significance level (p-value).
4. Line 440 The discussion section can further explore the biological implications of the experimental results. For instance, why does high-phosphorus treatment perform better in the early growth stage? Why do different nutrients exhibit distinct accumulation patterns in various organs? These phenomena can be explained and speculated upon by integrating existing research findings.
5. Line 569 The conclusions need to be more cautious to avoid overgeneralization. Since the experiment was conducted under specific conditions, the conclusions should be limited to these contexts. It is advisable to emphasize the study's limitations and propose directions for future research.

Comments for author File: Comments.pdf

Author Response

Reviewer 1

1. Some changes have been made to the abstract and, above all, more information has been added with the main results and conclusions, as suggested and highlighted in red in the current text.
2. Some changes were made, highlighting the importance of researches about seed production in the organic system and the problems arising from the lack of seeds produced in this system in Brazil, as suggested and highlighted in red in the current text.
3. Some information has been added, as suggested and highlighted in red in the current text.
4. Some changes were made to the discussion, as suggested and highlighted in red in the current text.
5. Some changes have been made. However, so as not to make the conclusions too long, some of the added information has been included in the discussion section (highlighted in red in the current text).

 

 

 

The results presented are correct, i.e. the accumulation of N in the 800 kg ha^-1 dose of P₂O₅ (1527.7 mg per plant) was lower than the accumulation in the 320 kg ha^-1 dose of P₂O₅ (1743.1 mg per plant). Only for N accumulation the lowest dose resulted in higher accumulation than the highest dose. The results were reviewed and this information was confirmed, as the N content of the lowest dose was higher than that of the highest dose.

2. The text is correct. Without considering the day of transplanting (0 DAT), another 7 samples were taken with 3 plants in each sample, each plant being considered a repetition, totaling 21 plants sampled throughout the cycle. Care was taken to collect only normal plants. In our experience, for this type of work, 3 repetitions in each sample is enough, except on the day of transplanting when the plants are still very small and don't have enough dry mass to take samples (a minimum of 1g of dry matter to carry out the analysis). This was the same methodology used by other authors who evaluated lettuce for seed production.
3. It has been corrected as requested by the reviewer.
4. Minor changes have been made to the text to make it clear when fertilizing before planting and when top dressing were performed.
5. It has been corrected as requested by the reviewer.
6. It has been corrected as requested by the reviewer.
7. It has been corrected as requested by the reviewer.
8. We didn't make any changes because we couldn't understand what the reviewer meant by “Dry matter accumulation in Table 2” and “cultivar names” in Table 3.
9. It has been corrected as requested by the reviewer.
10. This work did not discuss the production and quality of the seeds produced. Several evaluations were made of production, germination, vigor, nutrient content and extraction in the seeds, including comparisons with an additional treatment with inorganic fertilizers. However, these results will be shown in another paper (there are 4 more extensive tables with results, which would make the paper too long). In addition, the aim of this work was to obtain and discuss the absorption of nutrients by the lettuce plant for seed producion in an organic system, assessing the plant's nutritional requirements at each stage throughout the cycle.
11. It has been corrected as requested by the reviewer.

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript has undergone revisions accordingly. In my opinion, it  is ready for acceptance.

Author Response

Reviewer 2

1. Introduction: It has been corrected as requested by the reviewer.

 

2. Materials and Methods

- As mentioned in the text, two doses were chosen, the first (320 kg ha^-1 of P₂O₅) is the dose recommended for lettuce production for leaf consumption in the official fertilization bulletin for the state of São Paulo, Brazil (Trani et al., 2022), and the second dose (800 kg ha^-1 of P₂O₅) was the best dose reported for seed production in previously published work (Kano, 2006; Kano et al., 2012).

- Description of soil correction and fertilization: It has been corrections as requested by the reviewer.

- Statistical Analysis: It has been corrected as requested by the reviewer.

 

3. Results

- p-values or confidence intervals: It has been corrected as requested by the reviewer.

 

4. Discussion

- “Potential limitations”: It has been corrected as requested by the reviewer.

- N accumulation: The results presented are correct, i.e. the accumulation of N in the 800 kg ha^-1 dose of P₂O₅ (1527.7 mg per plant) was lower than the accumulation in the 320 kg ha^-1 dose of P₂O₅ (1743.1 mg per plant). Only for N accumulation was the lowest dose higher than the highest dose. The results were reviewed and this information was confirmed, as the N content of the lowest dose was higher than that of the highest dose.

Reviewer 3 Report

Comments and Suggestions for Authors

Accept in present form.

Author Response

Reviewer 3

- Regarding the importance of climate (temperature and photoperiod) we have added a paragraph in the “Discussion” of the results not in the “Introduction”, because we think that is better in the “Discussion”.

- Materials and Methods: It has been corrected as requested by the reviewer.

- Results: the paper already has a large number of figures (11 figures, some with 2 to 4 different graphs) and we felt that putting the data in a table would make the work too long and duplicate results. With the equations presented in the figures, it is possible for any reader to estimate the value of any data they want to see. This is why we prefer not to include new numerical tables in the results.

- Conclusion: If the research had been carried out in the conventional system, it would have been possible to make fertigation recommendations based on the results of the daily accumulation of nutrients. However, in the organic system, the fertilizers used are not ready to release nutrients, which makes it difficult to make a single recommendation. With the results obtained, the grower (or company) can make adjustments to the amount of nutrients and the times when they are applied. However, this recommendation will vary according to the source/ fertilizer used, climatic conditions and other factors. Fertilization recommendations in the organic system are not so easy to make. Research such as this can help producers and companies to improve nutritional management, but this work alone is not enough to make a valid recommendation for different situations.