Vermiliquer (Vermicompost Leachate) as a Complete Liquid Fertilizer for Hydroponically-Grown Pak Choi (Brassica chinensis L.) in the Tropics
Round 1
Reviewer 1 Report
Some of the cited sources are not appropriate or has no relevance at all. The paper described the product as liquid that drains out of the vermibeds after watering, but the sources cited to support the statement in the manuscript described a product that was extracted in a different manner and hence has no relevance.
The Studies (or experiments) are inadequately described i.e. treatments, number of treatments, number of replications, how the treatments were administered, etc. Additionally, the number of treatments and replications are two few to warrant a meaningful statistical comparisons, analysis and conclusions. Some clues of these missing details can be found in tables presented.
It seems that vermiliquers was obtained as soon as watering of vermibeds commenced (after earthworm inoculations), in which case, the raw materials are not well processed yet by earthworms and therefore would have very minimal contents in terms if nutrients, humic acids or hormones. Maturity of the product is described inadequately. This would further mean that vermiliquer extracted later would have a completely different of biochemical properties due to the state of decomposition of the raw material as vermicomposting progresses.
Author Response
Reviewer1
Some of the cited sources are not appropriate or has no relevance at all. The paper described the product as liquid that drains out of the vermibeds after watering, but the sources cited to support the statement in the manuscript described a product that was extracted in a different manner and hence has no relevance.
Our response: We disagree, the only difference between our method and others cited is that we recycled the vermiliquer from the tank to the vermibeds and cyclically back again, whereas studies for example by Garcia-Gomez et al (2008) and Gutierrez-Miceli et al. (2008) simply collected vermiliquer over 8 week vermicomposting periods, similar to ours. The nutrient content of our vermiliquer and others cited is very similar. Therefore, the cited sources are very relevant
We have removed two references to compost tea, and disease suppression (Haggag et al., 2007, Scheuerell and Mahaffee, 2006), which are only marginally relevant to the introduction to our study.
The Studies (or experiments) are inadequately described i.e. treatments, number of treatments, number of replications, how the treatments were administered, etc. Additionally, the number of treatments and replications are two few to warrant a meaningful statistical comparisons, analysis and conclusions. Some clues of these missing details can be found in tables presented.
Our response: for brevity, all the details on number of treatments and replications and plot size are included in lines 186-191 and Table 2. We have now added detail on number of replications and plot sizes to the text in section 2.5. Experimental Designs in the revised Word version, lines 183-234. We disagree that ‘the number of treatment and replications are too few to warrant a meaningful comparison, analysis and conclusions’. We subjected all data to ANOVAs and as seen in the Tables and Figures, meaningful differences were forthcoming, and we use these to support our discussion and conclusions.
It seems that vermiliquers was obtained as soon as watering of vermibeds commenced (after earthworm inoculations), in which case, the raw materials are not well processed yet by earthworms and therefore would have very minimal contents in terms if nutrients, humic acids or hormones. Maturity of the product is described inadequately. This would further mean that vermiliquer extracted later would have a completely different of biochemical properties due to the state of decomposition of the raw material as vermicomposting progresses
Our response: we disagree, the duration of processing of raw materials by earthworms was eight to ten weeks, as indicated in Lines 138-139 in the initial pdf submission, and lines 132-133 in the revised Word version, and the chemical compositions are presented for most of the Studies in Table 1. This uniform timing allowed for some consistency in chemical composition between each trial. With a living system it is impossible to obtain exactly similar concentrations of nutrients in each Study. Since the reviewer missed this crucial piece of information, we have included it in the revised Word abstract, lines 16, which reads: “based entirely on pH buffered vermiliquer, collected after 8-10 weeks of vermicomposting, was”
Author Response File: 
Author Response.docx
Reviewer 2 Report
Dear corresponding author, Dr. Midmore
I reviewed a manuscript entitled “Vermiliquer (vermicompost leachate) as a complete liquid fertilizer for hydroponically-grown pak choi (Brassica chinensis L.) in the tropics” submitted to “Horticulturae” as an Article by E. V. Churilova and D. J. Midmore. This paper studied use of vermiliquer as a liquid fertilizer on hydroponic cultivation of Pak Choi and finally pH control of the vermiliquer by nitric acid was identified as effective buffering agent. To lead this conclusion, authors conducted 8 independent experiments for 2 years in total.
In other words, only study III was sufficient to lead this conclusion. Other experiments and obtained data are not effectively presented to lead conclusion, rather, they are partly redundant or very fragmental. I do not understand necessity of all the figures presented in the manuscript in terms of both logical relevance and quality of presentation. In addition, following conclusion “For certified organic production with vermiliquer alternative acids will be required” seems to deny significance of all the experiments you shown. If I were you, at least, following basic manners should be considered to try submission in the future:
Significant digits
(for example, Table 2, 3 and Figure 4)
SI unit
(for example, mS/cm -> dS/m)
Delete horizontal ruled lines in figure
(for example, Figure 1, 2, 3, 5, 6, 7, 8)
Delete vertical ruled lines in table
(for example, Table 4)
Add academic name for vegetable plants such as potato (line 60), bitter melon (line 60), Chinese cabbage(line 63) and so on.
By the way, Line 515-516: You said that addition of 1 L of 10% HNO3 to 100 L vermiliquer results in 22 mg N/L. Is this correct?
Author Response
I reviewed a manuscript entitled “Vermiliquer (vermicompost leachate) as a complete liquid fertilizer for hydroponically-grown pak choi (Brassica chinensis L.) in the tropics” submitted to “Horticulturae” as an Article by E. V. Churilova and D. J. Midmore. This paper studied use of vermiliquer as a liquid fertilizer on hydroponic cultivation of Pak Choi and finally pH control of the vermiliquer by nitric acid was identified as effective buffering agent. To lead this conclusion, authors conducted 8 independent experiments for 2 years in total.
Our response: yes we did show that nitric acid is an effective buffering agent, but our eight Studies did much more than just that, and our Abstract and Conclusions indicate so. As we say in the original abstract, we also show that (a) direct linkage of hydroponics to vermiculture is not successful, (b) dilution of the vermiliquer to 50% resulted in a less than proportional reduction in yield, (c) that growth of pak choi did not differ between different sources of vermiliquer, and that (d) with vermiliquer nutrient supply, under less favourable (hotter) conditions pot culture is superior to NFT.
In other words, only study III was sufficient to lead this conclusion. Other experiments and obtained data are not effectively presented to lead conclusion, rather, they are partly redundant or very fragmental. I do not understand necessity of all the figures presented in the manuscript in terms of both logical relevance and quality of presentation. In addition, following conclusion “For certified organic production with vermiliquer alternative acids will be required” seems to deny significance of all the experiments you shown. If I were you, at least, following basic manners should be considered to try submission in the future:
Our response: each Study investigated a different factor that relates to the use of vermiliquer for hydroponics, and these were spelt out in lines 193-205 of the original pdf submission [now lines 190-192 and 217-234 in the revised Word submission. Results of each are presented separately in the Results section, with reference to Figures and Tables illustrating the various treatment effects.
The fact that our studies used nitric acid as a buffer negates the certification of the system for organic production is a fact, and anyway certified organic production does not allow for hydroponics [something that will need to be changed in the future], so we have now explicitly indicated that in lines 736-737 in the revised Word version.
Significant digits
(for example, Table 2, 3 and Figure 4)
Or response: data in Table 1 are mean values, correct to 1 g. We weighed to 1 g on our balance and feel that presentation as such is justified. In Table 2 these are the data as submitted by the CSB laboratory mentioned in Lines 169/170 in the original submission and mentioned in Table 3. We are willing to reduce the number of significant digits if requested. We cannot see any issue with significant digits in Figure 4.
SI unit
(for example, mS/cm -> dS/m)
Our response: we appreciate the pointing out that Figure 6 uses mS/cm, and this is now changed in the revised version, all other instances use dS/m.
Delete horizontal ruled lines in figure
(for example, Figure 1, 2, 3, 5, 6, 7, 8)
Our response: this is now changed in the revised version.
Delete vertical ruled lines in table
(for example, Table 4)
Our response: this is now changed in the revised version.
Add academic name for vegetable plants such as potato (line 60), bitter melon (line 60), Chinese cabbage(line 63) and so on.
Our response: this is now changed in the revised version, for all plant species mentioned.
By the way, Line 515-516: You said that addition of 1 L of 10% HNO3 to 100 L vermiliquer results in 22 mg N/L. Is this correct?
Our response: Yes the reviewer is correct in that 22 mg/L is not correct, in fact it should be 222 mg/L and this is now changed in the revised Word version, line 546.
Author Response File: Author Response.docx
Reviewer 3 Report
Tin the affirmation: "The importance of adjusting the pH of vermiliquer downwards in order for it to be used as a liquid hydroponic fertiliser, giving fresh yields comparable to an inorganic nutrient source, has been demonstrated" should be mentionated that only for pak choi cultivation.
letters for statistical significance in tables could be in normal size. Also include leyend "median with different letters was different statistical significance (p<0.05).
Author Response
Reviewer 3.
Tin the affirmation: "The importance of adjusting the pH of vermiliquer downwards in order for it to be used as a liquid hydroponic fertiliser, giving fresh yields comparable to an inorganic nutrient source, has been demonstrated" should be mentionated that only for pak choi cultivation.
This is now changed in the revised version, lines 730-732.
letters for statistical significance in tables could be in normal size.
We have now changed the size of the letter for MRT in all the Tables in the revised version
Also include leyend "median with different letters was different statistical significance (p<0.05).
Our data are means in the Tables, i.e., the ‘average’ where we add up all the values and then divide by the number of values, not ‘median’ for ‘median is the "middle" value in the list of values.
Author Response File: Author Response.docx
Round 2
Reviewer 2 Report
English writings are sometimes redundant and difficult to understand.
Quality of figures is still low, but this is totally due to authors. However, at least, explanation on y axis should be set with figure title in Figure 6. Add explanations of plots and vertical bars in Figures 2, 5, 7 and 8.
Figure 4 shows regression line with same slope value (-0.329) but green and red lines seem to have different slope. Please check.
Author Response
English writings are sometimes redundant and difficult to understand.
Response: We have read through and cannot identify where the English language is difficult to understand. We have however, clarified in simple instances the text [e.g., line 55-56, 58, 150, 246].
Quality of figures is still low, but this is totally due to authors. However, at least, explanation on y axis should be set with figure title in Figure 6. Add explanations of plots and vertical bars in Figures 2, 5, 7 and 8.
Response: We have endeavoured to improve the Figures, with the full set of treatment captions included in Figure 6 [the control caption was previously hidden from view]; we have included detail in the y-axis captions in Figures 6 and 7 and indicated that the vertical bars represent the SD of the mean in the appropriate Figure captions.
Figure 4 shows regression line with same slope value (-0.329) but green and red lines seem to have different slope. Please check.
Response: We undertook a statistical comparison of regression slopes and intercepts [more detail included in Section 2.7] and the analysis indicated that the slopes were common for both regressions, but the intercepts differed. This result is included in Figure 4 caption and the text, the latter emphasising that over the range 23 to 34 oC at a given temperature the control contained more dissolved oxygen than the vermiliquer.
