Biochar and Vermicompost Amendments Affect Substrate Properties and Plant Growth of Basil and Tomato
Round 1
Reviewer 1 Report
This manuscript deals with the effect of biochar and vermicompost on basil and tomato plant at nursery condition. Overall evaluation: This article needs to minor modifications, detailed below.
Comments
In this study, the treatments are mainly compared based on above ground biomass, shoot system, how about root system, have the authors measured root dry weight? To compare the robustness and biomass distribution equilibrium in the seedlings, the quality index of Dickson could be a good option to calculate, see Eskandari et al. 2019. Hydrochar-amended substrates for production of containerized pine tree seedlings under different fertilization regimes. Agronomy 9: 350. That would be great if the authors can provide the nutrient concentrations of the peat, biochar and vermicompost used in the study. Results show that seedlings in BC:VC mixes have similar or higher growth index than commercial substrate, however which biochar rate or VC rate is recommended as there is a big range in mixes , BC (20%, 40%, 60%, or 80%), VC (5%, 10%, 15%, or 20%).
Author Response
Point 1: In this study, the treatments are mainly compared based on above ground biomass, shoot system, how about root system, have the authors measured root dry weight? To compare the robustness and biomass distribution equilibrium in the seedlings, the quality index of Dickson could be a good option to calculate, see Eskandari et al. 2019. Hydrochar-amended substrates for production of containerized pine tree seedlings under different fertilization regimes. Agronomy 9: 350.
Response 1: Yes, we have measured root dry weight and it was shown in Fig 7 (b) and 8 (c). We have carefully checked the manuscript by Eskandari et al. 2019. Quality index of Dickson (QID) is one of the most comprehensive indices evaluating seedling quality, but our research evaluated the plant not seedling growth. And, unfortunately, we could not calculate the QID now since the stem diameter was not measured during our research.
Point 2: That would be great if the authors can provide the nutrient concentrations of the peat, biochar and vermicompost used in the study.
Response 2: The nutrient concentration (N, P, K, Ca, Mg, S, B, Ca, Cu, Fe, Mn, Na and Zn) of the commercial substrate, biochar and vermicompost are added and shown in Table 1 (Line 180).
Point 3: Results show that seedlings in BC:VC mixes have similar or higher growth index than commercial substrate, however which biochar rate or VC rate is recommended as there is a big range in mixes, BC (20%, 40%, 60%, or 80%), VC (5%, 10%, 15%, or 20%).
Response 3: All the BC and VC mixes in this research were recommended. If considering the cost, 80BC:5VC was the cheapest and the most recommended, which was concluded in Line 468-472.
Reviewer 2 Report
The paper deals with the potential of the mixed substrates of hardwood Biochar (BC) and Vermicompost (VC) as replacements for commercial peat-based container substrate. The manuscript presents the results on the physical and chemical properties of the BC and VC and the results on the impact of the different mixtures on grown basil and tomato plants compared to a peat-based commercial substrate.
That object as well as additional investigationis of value in the today's scientific literature. The basic idea and the approach of the subject are interesting, while moreover the economical perspective, as presented in the manuscript, support the effort to more investigation in that approach.
Therefore I suggest to be published after some revision needed according the following comments.
Title: The title should be revised including the names of crops.
Abstract: This part should be revised. Authors should add some data on this section. Also, the authors should change that names of treatments including the percentage of commercial substrate (e.g. 20:5:75). The latter changes should be made also in the main text and figures.
Introduction: This section is well written.
Line 45: “And BC could fix” should be changed as “ Moreover, BC could fix”.
Material and methods: This section is well written.
Lines 132-134: On the x axis of Figure 2 the percentage of commercial substrate on the seventeen substrates should be included and then the legend of the figure should be revised accordingly.
Statistical analysis: In this section authors reported that compared the sixteen treatment with the control. Authors should compare all the treatments and these results should be presented in figures.
Results and discussion:
Authors should add data about N, P, K content in substrates if these are available.
The treatments names in the text and figures should be changed including the percentage of commercial substrate (previous comment).
Figure 7. Instead of total dry weight of roots and shoot authors should be presented data about shoot to root ratio of basil plants.
Figure 8. Authors present data about the flowers+fruits dry weight. Information about the maturity stage of the fruits should be added. Probably the harvested fruits are not mature and was very small. It is better, authors should present information about flowers numbers, fruit number, and fruit yield per plant. Also, Instead of total dry weight of roots, shoot, flowers and fruits, authors should be presented data about shoot to root ratio of tomato plants.
In figures 7 and 8 it is not obvious if the presented values are per plant.
Figure 4: Y axis should start at pH 4. Thus, the differences between treatments should be more obvious.
Figure 5: Y axis should start at SPAD reading 20. Thus, the differences between treatments should be more obvious.
References
Authors should correct the references following the instructions for authors (e.g. the Journal names should be abbreviated)
Author Response
Point 1: Title: The title should be revised including the names of crops.
Response 1: The title has been revised.
Point 2: Abstract: This part should be revised. Authors should add some data on this section. Also, the authors should change that names of treatments including the percentage of commercial substrate (e.g. 20:5:75). The latter changes should be made also in the main text and figures.
Response 2: We have added more data on the Abstract Section and changed all the names of treatments as requested in the main text and figures.
Point 3: Introduction: This section is well written.
Line 75: “And BC could fix” should be changed as “Moreover, BC could fix”
Response 3: This sentence has been revised in Line 75.
Point 4: Material and methods: This section is well written.
Lines 177-179: On the x axis of Figure 2 the percentage of commercial substrate on the seventeen substrates should be included and then the legend of the figure should be revised accordingly.
Response 4: All the figures and legends have been revised.
Point 5: Statistical analysis: In this section authors reported that compared the sixteen treatment with the control. Authors should compare all the treatments and these results should be presented in figures.
Response 5: We have changed our statistical analysis to Tukey’s HSD tests to compare all the treatments. And all the results and figures are revised based on the new statistical analysis.
Point 6: Results and discussion:
Authors should add data about N, P, K content in substrates if these are available.
Response 6: The nutrient concentration (N, P, K, Ca, Mg, S, B, Ca, Cu, Fe, Mn, Na and Zn) of the commercial substrate, biochar and vermicompost are added and shown in Table 1 (Line 180).
Point 7: The treatments names in the text and figures should be changed including the percentage of commercial substrate (previous comment).
Response 7: The treatments names in the text and figures were all changed including the percentage of commercial substrate.
Point 8: Figure 7. Instead of total dry weight of roots and shoot authors should be presented data about shoot to root ratio of basil plants.
Response 8: This research is intended to test the whole plant growth to decide whether the mixed hardwood biochar and vermicompost mixes could be used as replacements for a commercial peat-based container substrate to grow plant. Shoot to root ratio is generally used in research conducted in drought environment, which we think may be not necessary in this study.
Point 9: Figure 8. Authors present data about the flowers+fruits dry weight. Information about the maturity stage of the fruits should be added. Probably the harvested fruits are not mature and was very small.
Response 9: The tomato fruit was not mature when harvesting. In this study, tomato and basil plants were used as model plants. Tomato plants are considered as “heavy feeder”, requiring medium to high fertility and basil is sensitive to high fertility. We aimed to test the vegetative growth of these two plants with different optimal growing conditions to decide whether the biochar and vermicompost mixes could be used as replacements for a commercial peat-based container substrate to grow plants. The aim of this study is not for fruit production. Also, once the plants go into the reproductive growth stage, a lot of nutrients of the plants would be taken for fruit growth and affect the whole plant mass, which is beyond the scope of the objective of testing the potential of using biochar in container to grow plants in this study.
Point 10: It is better, authors should present information about flowers numbers, fruit number, and fruit yield per plant. Also, instead of total dry weight of roots, shoot, flowers and fruits, authors should be presented data about shoot to root ratio of tomato plants.
Response 10: As mentioned above, this research is intended to test the whole plant growth to decide whether the mixed hardwood biochar and vermicompost mixes could be used as replacements for a commercial peat-based container substrate to grow plant. The aim is not for fruit production. Therefore, we did not count flower numbers, fruit numbers and fruit yield. And shoot to root ratio is generally used in research conducted in drought environment, which we think may be not necessary in this study.
Point 11: In figures 7 and 8 it is not obvious if the presented values are per plant.
Response 11: The presented values are actually per plant. I have corrected the way of writing to avoid misunderstanding.
Point 12: Figure 4: Y axis should start at pH 4. Thus, the differences between treatments should be more obvious.
Figure 5: Y axis should start at SPAD reading 20. Thus, the differences between treatments should be more obvious.
Response 12: We have changed the Y axis of the figures to start at pH 4 at Fig 4 and SPAD 20 at figure 5. And the differences between the treatments were decided based on the statistical analysis.
Point 13: References:
Authors should correct the references following the instructions for authors (e.g. the Journal names should be abbreviated)
Response 13: I have significantly corrected all the references.
