Effect of Peat-Perlite Substrate Compaction in Hiko V265 Trays on the Growth of Fagus sylvatica L. Seedlings

Round 1

Reviewer 1 Report

The manuscript by Pajak et al., has been reviewed. The manuscript shows the importance of peat-perlite concentrations on the growth of European beech a native species o central and west Europe. The manuscript is of high relevance to horticultural issues. I found this manuscript suitable for publication subject to the following changes. 

The abstract needs to be re-written. Highlight the importance and the problem statement in first lines. What is the take home message?Should be mentioned in last lines

Introduction: While the introduction is well written and the story describes the content logically, there is a strong need to  write the objectives and hypothesis precisely. What is different in this study which has not been done in previous ones?

Line 78, remove T.

There is a strong need to split the whole M&M section into subheadings.

Details on the treatment plan and variants prepared is crucial and should be given in detail.

From all the results, please mention which variant performed well on which results. Follow this trend for all the results.

Table 2, Why there is only statistical analysis for SH only? Please provide analysis for other parameters too. Check table 3 too.

Please mention all the variants in all figure and table footnotes.

I suggest writing the conclusion as a single paragraph and not as bullets. Highlight limitations of the study and future implications.

Author Response

We are grateful to the Reviewer for the insightful comments which enabled us to improve the paper. We agree with the remarks and we have modified the paper accordingly. Below is the summary of changes made in response to each comment.

1. Comment: The abstract needs to be re-written. Highlight the importance and the problem statement in first lines. What is the take home message? Should be mentioned in last lines

Response: We thoroughly rewrote the abstract. We outlined the problem statement in the first lines and gave the take home message in the last lines.  

“The growth of seedlings depends on many factors: the availability of light, water and minerals as well as the type and physical properties of the substrate, including its density. The effect of different levels of compaction of the peat - perlite substrate on the growth of European beech (Fagus sylvatica L.) seedlings in container nursery has not been investigated so far. In presented research nine variants of peat–perlite substrate compaction (in 3 replications), with the actual bulk density ranging between 0.196 and 0.317 g·cm^–3, were prepared in Hiko V265 nursery trays. European beech seeds were sown in the trays, and a seedling was grown in the production field. After the cultivation period, selected parameters have been measured. The results revealed that substrate in a wide range of compaction (dry bulk density: 0.078–0.127 g·cm^–3) had an impact on the height of seedlings, root dry matter, and the mean length of coarse roots and fine roots. The best shoot-to-root ratio and sturdiness quotient were observed in the seedlings growing on the substrate with the lowest compaction. Based on the results compaction at the level of 0.196 g·cm^–3 is recommended for the cultivation of European beech in Hiko V265 nursery trays.” 

2. Comment: : Introduction: While the introduction is well written and the story describes the content logically, there is a strong need to write the objectives and hypothesis precisely. What is different in this study which has not been done in previous ones?

Response: We wrote the hypothesis precisely in the introduction (page 2) and we have added information on how our incidence differs from others.

“The research on the impact of compaction most often concerns agriculture and there is scarcely any research on the peat substrate compaction (especially in such a wide range of compactions) in container nurseries. The density level used in container nurseries is chosen based on intuition and experience of forest nursery employees. The same level of compaction is most often used for each species grown at one nursery. For specific species, there is insufficient research on whether very high or very low densities affect the growth of the species and what is the optimal compaction of the perlite-peat substrate.

In the present study, the following hypothesis was tested for European beech (Fagus sylvatica L.) seedlings grown in Hiko V265 containers: there is an optimum peat-perlit compaction at which the grown seedlings will have the desirable growth parameters (al-lometric) for good adaptation on the crop, i.e., the value of the S/R should equal to or be below 2 (S/R≤2:1) and the SQ should be below 6.5 (SQ≤6.5).”

3. Comment: Line 78, remove T.

Response: We removed T.

4. Comment: There is a strong need to split the whole M&M section into subheadings.

Response: We split the whole M&M section into 4 subheadings (Levels of compaction, Plant growth, Laboratory analysis, Statistical analysis).

5. Comment: Details on the treatment plan and variants prepared is crucial and should be given in detail. 

Response: We have added more details about the production of the seedling (fertilization, protection, weeding) and in addition we have added a reference (Szabla, K.; Pabian, R. Szkółkarstwo Kontenerowe: Nowe Technologie i Techniki w Szkółkarstwie Leśnym; Centrum Informacji Lasów Państwowych: Warszawa, 2009; ISBN 978-83-89744-80-7.) in which the entire production process in the considered container nursery is described in great detail.

6. Comment: From all the results, please mention which variant performed well on which results. Follow this trend for all the results.

Response: Often there is no single variant achieving the best parameters. The results section includes information on which group of variants performs best on which results. This information is included only for statistically significant results (as multiple reviewers suggested to omit the results that are not statistically significant).

7. Comment: Table 2, Why there is only statistical analysis for SH only? Please provide analysis for other parameters too. Check table 3 too.

Response: We have added the statistical analysis in both tables.

8. Comment: Please mention all the variants in all figure and table footnotes.

Response: Under each figure, we added information which variant corresponds to which value of the dry bulk density (Values of dry bulk density (in g·cm–3) for each variant: V1=0.078, V2=0.085, V3=0.091, V4=0.097, V5=0.103, V6=0.109, V7=0.115, V8=0.121, V9=0.127).

9. Comment: I suggest writing the conclusion as a single paragraph and not as bullets. Highlight limitations of the study and future implications.

We wrote the conclusions as a single paragraph and added a promising direction for future research that is very related to the limitations of the study.

Added to conclusion:

“The obtained results of the study indicate that a low level of peat-perlite substrate compaction is recommended for breeding European beech seedlings in nursery trays in Hiko V265. Since the highest level of substrate compaction applied in the study did not cause inhibition of seedling growth, additional research using another kind and size of nursery trays is needed to verify whether the substrate compaction at bulk densities above 0.317 g·cm–3  limits the growth responses of European beech seedlings.”

The details about the limitations of the study are given in section 4.

Reviewer 2 Report

Attached herewith is the manuscript with remarks 

Comments for author File: Comments.pdf

Author Response

We are grateful to the Reviewer for the insightful comments which enabled us to improve the paper. We agree with the remarks and we have modified the paper accordingly. We made the language corrections as requested. Below is the summary of changes made in response to the other comments.

1. Comment: Experiment factors and their distribution is unclear

Response: We thoroughly rewrote the abstract. We outlined the problem statement in the first lines and gave the take home message in the last lines.

“The growth of seedlings depends on many factors: the availability of light, water and minerals as well as the type and physical properties of the substrate, including its density. The effect of different levels of compaction of the peat - perlite substrate on the growth of European beech (Fagus sylvatica L.) seedlings in container nursery has not been investigated so far. In presented research nine variants of peat–perlite substrate compaction (in 3 replications), with the actual bulk density ranging between 0.196 and 0.317 g·cm^–3, were prepared in Hiko V265 nursery trays. European beech seeds were sown in the trays, and a seedling was grown in the production field. After the cultivation period, selected parameters have been measured. The results revealed that substrate in a wide range of compaction (dry bulk density: 0.078–0.127 g·cm^–3) had an impact on the height of seedlings, root dry matter, and the mean length of coarse roots and fine roots. The best shoot-to-root ratio and sturdiness quotient were observed in the seedlings growing on the substrate with the lowest compaction. Based on the results compaction at the level of 0.196 g·cm^–3 is recommended for the cultivation of European beech in Hiko V265 nursery trays.” 

2. Comment: keywords are very complicated, its need to rewrite again, try to used single words

Response: We agree with this comment and we changed some of the keywords to simpler phrases, if possible: seedling root traits to root traits, stem-to-root ratio to root shoot ratio

3. “Therefore, it can be assumed that the SQ value of beech seedlings bred in trays should not exceed 6.5. The S/R value determines the balance between the area of transpiration and the area of water absorption. For seedlings growing in soil, the S/R value should not exceed 3:1, while for seedlings growing in trays, it should be 2:1” (Comment: rewriting again)

Response: We rewrote the paragraph about SQ and S/R values and improved its clarity and style.

“In ground nurseries, for 1^st class seedlings, the value of SQ is 6.3, and for 2^nd class seedlings, it is 6.7. In the absence of recommended values of SQ for container nurseries, for the purpose of this experiment we set SQ to be at most 6.5. For seedlings growing in soil, the S/R value should not exceed 3:1, while for seedlings growing in trays, it should be 2:1”

4. “The cells in the tray taper down and are equipped with vertical guides for the root system. A total of 9 variants with different levels of peat–perlite substrate compaction were prepared. The minimum bulk density (V1 variant) was achieved by filling a single cell with uncompacted substrate  of 60% humidity, which was subsequently poured out and weighed.” (Comment: Consider rewriting this sentences)

Response: To facilitate the understanding of this part, we rewrote the explanation of the process of preparing the samples.

”The minimum bulk density (V1 variant) was achieved by filling by hand a single cell with un-compacted, loose substrate of 60% humidity, which was subsequently poured out and weighed. The procedure was repeated 3 times, and after averaging for V1 variant, a substrate with a weight of 52.0 ± 0.2 g was obtained. The substrate in variant with maximum compaction (V9) was compacted using a wooden stamp until the cell in the tray is completely filled, next the substrate were poured out of the cell and weighed. The procedure was repeated 3 times and the average weighty of the three samples was calculated. A variant with maximum compaction (V9) with a weight of 84.0 ± 0.3 g was obtained. For variants V2–V8, the substrate mass was calculated by equally dividing the mass of extreme compaction variants ((84.0 g – 52.0 g) : 8 = 4)  and an increase in weight in subsequent variants by 4 g (Table 1). Next, for each variant, the substrate was filled in 3 trays (replications), by pouring the calculated substrate mass to a cell, weighed on the analytical scale with an accuracy of ±0.1 g. Each cell of the tray was filled by hand.”

5. Comment : The experiment date was in 2015, but the submission is in 2022. The difference is approximately six years, which Should the author be cleared its cause.

Response: Cultivation procedure of seedlings in container nurseries has not changed since the experiment has been conducted. The time gap between the experiment and the submission is due to the agreement with the funding organization.

6. Comment : Table 2). The highest leaf surface area was noted in the 2 extreme substrate compaction variants (V1 and V9), but the values did not statistically significantly differ from that of the remaining variants (Table 2).

            Response: In Tables 2 and 3 we have added the statistical analysis.

7. “However, high variability of results was not observed for the mean values of compaction. The highest value of determination coefficient (76%) was obtained for the leaf dry weight, a lower value for stem dry weight (54%), and the lowest for root dry weight (43%) (Fig. 2). For roots, the value of R2 reached approximately 50% for parts (a) and (b) (Fig. 3). The most pronounced influence of compaction was noted for part (c) of root, with as much as 80% of dry weight variability explained by the change in substrate compaction. (Comment: unclear, rewriting again)

Response: The confusion was probably due to an incorrect word (mean). We changed it (mean to medium) and the meaning of the paragraph should be clearer now. 

8. 76% - from point 7 (Comment: What is the best variant, and what is the lowest)

Response: The aim of this part was to highlight which features (dry mass of which part of seedlings) were the most influenced by the bulk density. The best/worst variant is discussed above in the text and in Table 3.

9. “Considering the ratio of SH to RCD, the best SQ was attained by seedlings from V1 variant (7.82), whereas the least favorable result was observed for V6 variant (10.35). V1 variant showed significant differences from the remaining results (Fig. 4)”. (Comment: Is the high SQ value good or bad the author should be mention that in the introduction.)

Response: In the introduction, we added the information about the meaning of the SQ values and the relation to seedling quality.

“The adaptive potential of seedlings is characterized by synthetic indicators [9,42–45], namely seedling sturdiness quotient (SQ) and stem-to-root ratio (S/R). SQ is a measure of seedling stability in the culture (resistance to wind and drought), with smaller values of SQ corresponding to more sturdy seedlings. According to Roller [46], the value of SQ depends on the species and type of nursery tray used for breeding.”

10. The contribution of seedlings with the best SQ and S/R coefficients decreased with increasing substrate compaction, while the contribution of seedlings that did not meet the qualitative requirements was over 50% when the dry bulk density was above 0.091 g·cm^–3 (V3) (Fig. 6). (Comment: please this section requires more clarification)

Response: We clarified the paragraph about percentage of seedlings with admissible values of SQ and S/R .

“The percentage of seedlings with admissible values of SQ and S/R (i.e., not exceeding the maximum defined for this experiment) decreased with increasing substrate compaction. When the dry bulk density was above 0.091 g·cm^–3 (V3) (Fig. 6), the percentage of seedlings with admissible values dropped below 50%.”

11. Comment: tomato is so far from your study plant

Response: We shortened our discussion slightly and focused only on closely relevant existing research. In particular, we removed the less related part of the discussion on the influence of soil compaction on tomato.

12. Comment: “should the highest value take (a) letter, do you have another explanation.,” “This variant is the highest value, why b letter used” , “here used letter it's really confused me, I think your data need revision.”

We reviewed the statistical analysis in these cases and could not find any error. The letters a-f are only group labels and do not indicate highest/lowest values of the considered parameters. The groups indicate which variants of substrate compaction result in similar values of the considered parameters.

13. Comment: if the values have not reached to significant effect why do you mention the highest and lowest values.

Response: We changed the description of the results and did not emphasize which variants are the best if they were not statistically significant.

Reviewer 3 Report

Although the abstract reports the main results, I think it should be better edited to highlight the importance of this study and the potential applications. 

The purpose of the study, I refer to the final part of the introduction, should be rewritten by better clarifying the aims of the work done.

Line 78: delete "T" at the beginning of the sentence
Lines 79-81: it would be appropriate to indicate the reasons or give bibliographic references to justify the use of these % peat and perlite.

156-161: if the parameters studied do not differ statistically there is no point in indicating which treatments had a higher RCD.

172-175: same as above

In general, the data presented in tables 4 and 5 have a large variability as indicated by SD. I suggest rechecking the statistical analysis.

The discussion can be shortened and more focused on the results obtained.

Author Response

We are grateful to the Reviewer for the insightful comments which enabled us to improve the paper. We agree with the remarks and we have modified the paper accordingly. Below is the summary of changes made in response to each comment.

1. Comment: Although the abstract reports the main results, I think it should be better edited to highlight the importance of this study and the potential applications

Response: We thoroughly rewrote the abstract. We outlined the problem statement in the first lines and pointed out the practical implications of the study at the end of the abstract.

“The growth of seedlings depends on many factors: the availability of light, water and minerals as well as the type and physical properties of the substrate, including its density. The effect of different levels of compaction of the peat - perlite substrate on the growth of European beech (Fagus sylvatica L.) seedlings in container nursery has not been investigated so far. In presented research nine variants of peat–perlite substrate compaction (in 3 replications), with the actual bulk density ranging between 0.196 and 0.317 g·cm^–3, were prepared in Hiko V265 nursery trays. European beech seeds were sown in the trays, and a seedling was grown in the production field. After the cultivation period, selected parameters have been measured. The results revealed that substrate in a wide range of compaction (dry bulk density: 0.078–0.127 g·cm^–3) had an impact on the height of seedlings, root dry matter, and the mean length of coarse roots and fine roots. The best shoot-to-root ratio and sturdiness quotient were observed in the seedlings growing on the substrate with the lowest compaction. Based on the results compaction at the level of 0.196 g·cm^–3 is recommended for the cultivation of European beech in Hiko V265 nursery trays.” 

2. Comment: The purpose of the study, I refer to the final part of the introduction, should be rewritten by better clarifying the aims of the work done.

Response: We wrote the hypothesis precisely in the introduction (page 2) and we have added information on how our incidence differs from others.

“The research on the impact of compaction most often concerns agriculture and there is scarcely any research on the peat substrate compaction (especially in such a wide range of compactions) in container nurseries. The density level used in container nurseries is chosen based on intuition and experience of forest nursery employees. The same level of compaction is most often used for each species grown at one nursery. For specific species, there is insufficient research on whether very high or very low densities affect the growth of the species and what is the optimal compaction of the perlite-peat substrate.

In the present study, the following hypothesis was tested for European beech (Fagus sylvatica L.) seedlings grown in Hiko V265 containers: there is an optimum peat-perlit compaction at which the grown seedlings will have the desirable growth parameters (al-lometric) for good adaptation on the crop, i.e., the value of the S/R should equal to or be below 2 (S/R≤2:1) and the SQ should be below 6.5 (SQ≤6.5).”

3. Comment: Line 78: delete "T" at the beginning of the sentence

Response: We removed T.

4. Comment: Lines 79-81: it would be appropriate to indicate the reasons or give bibliographic references to justify the use of these % peat and perlite.

Response: We added information on the composition of the substrate:

“The proportion of perlite to peat is selected individually by substrate producers for each batch of the substrate in accordance with the guidelines (Szabla, K.; Pabian, R. Szkółkarstwo Kontenerowe: Nowe Technologie i Techniki w Szkółkarstwie Leśnym; Centrum Informacji Lasów Państwowych: Warszawa, 2009; ISBN 978-83-89744-80-7).”

5. Comment: 156-161: if the parameters studied do not differ statistically there is no point in indicating which treatments had a higher RCD. And 127-125 lines.

Response: We changed the description of the results and did not emphasize which variants are the best if they were not statistically significant.

6. Comment: In general, the data presented in tables 4 and 5 have a large variability as indicated by SD. I suggest rechecking the statistical analysis.

Response: We checked the statistics and confirmed a large variation in these results.

7. Comment: The discussion can be shortened and more focused on the results obtained.

Response: We shortened our discussion. In particular, we removed the less relevant part of the discussion on the influence of soil compaction on tomato (as suggested by other reviewers).

Reviewer 4 Report

Dear Authors, Your contribution has a valuable scientific output and a broad practical basis. Some additional explanations and corrections should be useful. The details are presented herewith below. Line 78 Excess "T". Lines 94-97 Similarly, a variant with maximum compaction (V9) with a weight of 84.0 ± 0.3 g was obtained. The substrate in this variant was compacted by whipping it with a wooden stamp until the cell in the tray is completely filled. For variants V2–V8, the substrate mass was calculated by equally dividing the mass of extreme compaction variants Maybe omit "whipping it"? The explanation is vague. It is impossible to understand a procedure of the variants V2–V8 preparation. The substrate density is extremely low. Please add references on this subject to the text. Table 1 Please explain why the actual bulk density is two times greater than the dry bulk density. It should be useful to assess a porosity of substrate. Line 115 Foliar Floralesad fertilizer and Florasin K 500 contain a great amount of N, K, less P. A dosage used in the experiment is rather high. Accounting the sprinkling irrigation of 904 mm, small substrate layer, and high substrate porosity, a greater part of fertilizer was leached. Please discuss our point of view. Lines 120-121 Throughout the vegetative season, the conductivity of the aqueous fertilizer solution was maintained at approximately 600 µS∙cm–1 Please explain how did you manage to do this. Table 2, Figure 1 A variability of data is high, most data are statistically insignificant. Lines 249-250 About 42% of root length variability was explained by the change in substrate compaction. This figure is not reliable. Lines 273-275 Similarly, Tracy et al. noted an increase in the growth of Solanum lycopersicum L. in clay-loam soils at a bulk density of 1.6 g•cm–3 and an optimum growth of plants in clay sand at 1.3 g•cm–3 Against these figures, you applied a ten times lower density of substrate. In this case, the data on the growth of plants in experiments of other authors to assess your own data should be suitable. Line 298-301 The present study revealed that increasing substrate compaction did not have an inhibiting effect on the dry weight of beech seedlings. A contrasting result was obtained in the study of Pan and Bassuk [28], in which the total dry weight of A. altissima Mill. Swingle seedlings was approximately 50% lower in variants with high compaction. Your highly variable data do not provide a general assessment of this kind. What substrate compaction was registered in the experiment of Pan and Bassuk? Line 317 r = 0.668 This level of correlation is not high. Lines 363-365 The obtained results of the study indicate that a low level of peat-perlite substrate compaction is required for breeding European beech seedlings in nursery trays. Accounting the data presented, this conclusion is not obvious. We propose authors to discuss following point of view: A precipitation and irrigation norm in experiment comprises of 78+904=982 mm. This level of water supply is capable to leach most applied fertilizers from substrate. Unfortunately, you did not present needed data. 

To avoid an excessive substrate humidification, we developed a Biogeosystem Technique (BGT*) methodology. You can assess new possibilities of soil humidification: DOI: 10.13187/bgt.2017.1.39;  https://doi.org/10.1021/acsomega.0c02448; https://doi.org/10.3389/fphy.2020.618320; https://doi.org/10.3389/fphy.2020.616385 It is especially emphasized that information about BGT* does not oblige to cite it.

Author Response

We are grateful to the Reviewer for the insightful comments and for pointing out additional references which enabled us to improve the paper. We agree with the remarks and we have modified the paper accordingly. Below is the summary of changes made in response to each comment.

1. Comment: Line 78 Excess "T".

Response:We removed T.

2. Comment: Lines 94-97 Similarly, a variant with maximum compaction (V9) with a weight of 84.0 ± 0.3 g was obtained. The substrate in this variant was compacted by whipping it with a wooden stamp until the cell in the tray is completely filled. For variants V2–V8, the substrate mass was calculated by equally dividing the mass of extreme compaction variants Maybe omit "whipping it"? The explanation is vague. It is impossible to understand a procedure of the variants V2–V8 preparation. The substrate density is extremely low. Please add references on this subject to the text.

Response: To facilitate the understanding of this part, we rewrote the explanation of the process of preparing the samples.

 ”The minimum bulk density (V1 variant) was achieved by filling by hand a single cell with un-compacted, loose substrate of 60% humidity, which was subsequently poured out and weighed. The procedure was repeated 3 times, and after averaging for V1 variant, a substrate with a weight of 52.0 ± 0.2 g was obtained. The substrate in variant with maximum compaction (V9) was compacted using a wooden stamp until the cell in the tray is completely filled, next the substrate were poured out of the cell and weighed. The procedure was repeated 3 times and the average weighty of the three samples was calculated. A variant with maximum compaction (V9) with a weight of 84.0 ± 0.3 g was obtained. For variants V2–V8, the substrate mass was calculated by equally dividing the mass of extreme compaction variants ((84.0 g – 52.0 g) : 8 = 4)  and an increase in weight in subsequent variants by 4 g (Table 1). Next, for each variant, the substrate was filled in 3 trays (replications), by pouring the calculated substrate mass to a cell, weighed on the analytical scale with an accuracy of ±0.1 g. Each cell of the tray was filled by hand.”

3. Comment: Table 1 Please explain why the actual bulk density is two times greater than the dry bulk density. It should be useful to assess a porosity of substrate. 

Response: We added the porosity values to Table 1 for each variant and information on the dry bulk density value resulting from the 60% moisture content of the actual bulk density of peat substrate.

4. Comment: Line 115 Foliar Floralesad fertilizer and Florasin K 500 contain a great amount of N, K, less P. A dosage used in the experiment is rather high. Accounting the sprinkling irrigation of 904 mm, small substrate layer, and high substrate porosity, a greater part of fertilizer was leached. Please discuss our point of view.

Response: We added the fertilization doses (Fertilization was carried out along with irrigation, 15x Floralesad in total (5x in the tent, 10x in the production field + 1x Florasin K with foliar fertilizers) and additional details on the seedling treatment and in addition we have added a reference (Szabla, K.; Pabian, R. Szkółkarstwo Kontenerowe: Nowe Technologie i Techniki w Szkółkarstwie Leśnym; Centrum Informacji Lasów Państwowych: Warszawa, 2009; ISBN 978-83-89744-80-7) in which the entire production process in the considered container nursery is described in great detail.

5. Comment: Lines 120-121 Throughout the vegetative season, the conductivity of the aqueous fertilizer solution was maintained at approximately 600 µS∙cm–1 Please explain how did you manage to do this. 

Response:  We added description of the method of measuring conductivity

“After the fertilizer had been poured into the fertilizer distribution on irrigation ramp, the conductivity test was made by hand tester on a sample.”

6. Comment: Table 2, Figure 1 A variability of data is high, most data are statistically insignificant. 

Response: In Tables 2 and 3 we have added the statistical analysis.

7. Comment: Lines 249-250 About 42% of root length variability was explained by the change in substrate compaction. This figure is not reliable.

Response: We corrected the mistake, the correct R2 is 0,1963

8. Comment: Lines 273-275 Similarly, Tracy et al. noted an increase in the growth of Solanum lycopersicum L. in clay-loam soils at a bulk density of 1.6 g•cm–3 and an optimum growth of plants in clay sand at 1.3 g•cm–3 Against these figures, you applied a ten times lower density of substrate. In this case, the data on the growth of plants in experiments of other authors to assess your own data should be suitable. 

Response: We shortened our discussion slightly and focused only on closely relevant existing research. In particular, we removed the less related part of the discussion on the influence of soil compaction on tomato.

9. Comment: Line 298-301 The present study revealed that increasing substrate compaction did not have an inhibiting effect on the dry weight of beech seedlings. A contrasting result was obtained in the study of Pan and Bassuk [28], in which the total dry weight of A. altissima Mill. Swingle seedlings was approximately 50% lower in variants with high compaction. Your highly variable data do not provide a general assessment of this kind. What substrate compaction was registered in the experiment of Pan and Bassuk?

Response: We have added information about compaction and type of substrate in the experiment of Pan and Bassuk

“The present study revealed that increasing substrate compaction did not have an inhibiting effect on the dry weight of beech seedlings. A contrasting result was obtained in the study of Pan and Bassuk at compaction 1.67g/cm³ and 1.88g/cm³ for mason sand and 1.30g/cm³ and 1.64g/cm³ sandy loam [31], in which the total dry weight of A. altissima Mill. Swingle seedlings was approximately 50% lower in variants with high compaction. Compared to the tested soils types peat is more difficult to compaction.“

10. Comment: Line 317 r = 0.668 This level of correlation is not high.

Response: The value of r Pearson coefficient of 0.668 can be seen as a sufficient level of correlation (according to Guilford's Classification). We agree that there are various interpretations of value r therefore we do not claim that the level of correlation is high but only that it is statistically significant.

11. Comment: Lines 363-365 The obtained results of the study indicate that a low level of peat-perlite substrate compaction is required for breeding European beech seedlings in nursery trays. Accounting the data presented, this conclusion is not obvious. We propose authors to discuss following point of view: A precipitation and irrigation norm in experiment comprises of 78+904=982 mm. This level of water supply is capable to leach most applied fertilizers from substrate. Unfortunately, you did not present needed data. 

Response: We added some discussion about the content of elements and compaction of the substrate in combination with the method of fertilization. 

“At the beginning of the experiment, the substrate used was sterile and contained no elements. Due to the small volume of the substrate in each cell tray, no soil fertilizers are used, because it could quickly be leached of the substrate. However, the elements appear in the substrate during cultivation from the foliar fertilizer. Differences in the physical properties (e.g. bulk density) of the substrate may have an impact on the amount of the elements retained in the substrate. 

Round 2

Reviewer 1 Report

The authors have done a good job in revision. 

Reviewer 2 Report

Thank you for revising the manuscript 

Reviewer 3 Report

The paper can be accepted for publication in the revised form