Comparison of Product Sustainability of Conventional and Low-Carbon Apples in Korea

Round 1

Reviewer 1 Report

Dear Authors,

I really enjoyed reading your study.

It is well designed and very well presented; it merits publication.

The only point that could be improved is this: could you please in lines 283-293 include the "cost" of a tone of CO2? and how much money in CO2 taxes would be saved for China if your suggestions were followed?

Thank you.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

1^st Reviewer

1. Title & Abstracts

Title: The title is representative of the article

Abstract: Quite good and concise. There is the statement, the aim the methodologies and the results, as well as the suggestion to improve GHGs based on the results

General comment: The author must add the significance of the work in comparison with existing research done

Please note that I revised the abstract before reading the whole manuscript. Additional comments on the abstract after reading the manuscript, if any, can be found at the end of this revision (Additional suggestions)

 

Introduction:

Line 33-34 : “ Agriculture….human use”. Her you must add a reference.

Line 54 : LOHAS; explain the acronym

Line 64-65: Not clear meaning in relation to “climate”.

General comment: Very general and narrative, mainly referring the framework of sustainability adoption by the country, without presenting the state of the art about conventional and low-input production systems (some statistics, other case studies). It seems to me like a review type article not a research article. Also, quite short.

 

Material and Methods:

2.1 Research Subject selection: Good justification of apple as subject of the study

2.2. Environmental Assessment: It needs reforming.

Initially, ISO based LCA follow specific steps that is not mentioned here. 1) Goal and scope, 2) Inventory analysis 3) Impact Assessment 4) Interpretation. In order to say that your LCA study is ISO-based you should follow close this structure. It seems to me that you are not following ISO based LCA methodology

Also, you refer Water footprint and Carbon footprint in line 84 without saying if this will be used in the study, thus being an irrelevant information.

Basic information that constitute the LCA methodology are missing, like:

1. What type of study it is? Is it “Gradle to Grave”?
2. Why using a mass-based FU (Line 87)?
3. Primary data are referred. Secondary data did you use? Which sources did you use? Did you use them as they were without adapting them in local situation?
4. What about the emissions during supply chain of all inputs (not only emissions during pear growing)?
5. The production stages that was included and excluded from system boundary (e.g. nursery process and planting)
6. Carbon dioxide uptake considered?
7. Human labor?
8. What about time boundary? It is referred that only one-year data are used. If only one productive year is considered, a significant underestimation of the environmental effects of the fruit production is occurring! It is a major limitation of the study.
9. What modelling approach did you used?
10. Data quality is mentioned without referred where it was based (reference)
11. Which method of Impact assessment did you use?
12. What about direct and indirect emissions’ calculation using equations based on Guidelines like IPCC etc.
13. In figure of system boundary, you include waste treatment that nowhere else is mentioned

 

Also consider the points below:

Line 85-87: “To benchmark… analyzes” Need to re-write, not clear meaning.

Line 88-89: “Figure1…steps”. Need to re-write, not clear meaning.

 

2.3 Cost analysis of apples

Line 108-109: Not clear what “respectively” mean. Clarify which corresponds to where

 

Results and Discussion

Line 124-126: Correct “This amount” into These amounts are..”. Please clarify if the yield of 2173 kg /10a accounts for conventional or for low-carbon. Also mention on the table caption inputs unit per area

Table 1 is presenting the inputs only. You should add also the outputs e.g   1 ton of apple  ?

Line131: “…greenhouse cultivation rate..” correct into “…greenhouse gas emissions cultivation rate..”

Line 131-133: “ On the contrary…. farming” the meaning is not clear.

Table 1 Can you explain why liquid fertiliser, eco fertilizers, Potassium and magnesium sulfate are higher for low carbon cultivation?

Line 137: Not clear meaning (hoe the table 1 show that GaBi LCA software was used?)

Line 158: Define cumulative sum of CO2.

Line 159: If consider GHGs the unit will be CO2 eq

Line 163: Not clear meaning

Line 168-169: Explain in brackets why low-carbon  uses excessive aoole pare cover

Line 170-172: Explain the outcome and also find if similar results are published  

Line 183: “ On the contrary” defines opposition Is this what you mean? If not it should be changed.

Line 185: “Therefore” should be changed with other word

Line 185-186: In term of land use … was analyzed to be 21 times…” of what? Not clear meaning

Line 187-190: More to be explained, too generic and controversial

Line 190: define direct and indirect water.

204-207: Clarify better

Line 215:  Add a reference about WF

Line 218: Cange the “worse: with higher

In Table 6 the last column is missing

Line 234: check the reference (I suppose is wrong)

Line 235-239: Not clear the meaning

Linw 243: Is 1.99 correct?

246-248: Please explain more. Especially line 248 is the meaning correct? The actual yield of low carbon was 3 times higher from conventional?

Table 7: check the table; Maintenance ratio

Lines 263-265: Please explain more

Line 281: “ which was reduced..” correct to “ which will be reduced…”

Line 282-283: Not clear

 

Genera Comment: Many points in this section are not comprehensive; they need to be written clearer giving more details. No references on similar published research is included. Results of environmental analysis are merely presented not following the structure of a common presentation of an LCA study. The economic analysis is quite well presented, although it has also points that needs to be more explained.

Also, you should Check numbering of Figures and Tables, there are flaws.

 

Conclusion

Line 307: The reference of “.. preventing future infectious diseases, such as COVID-19” is not relevant with the paper. Likewise line 318-319,

General comment.

The conclusion supports the subject of the article, but also they are too narrative

NOVELTY, LIMITATION AND ADDITIONAL SUGGESTION

The novelty of the paper is not mentioned 

Main limitation in the paper concern the LCA methodology they claim that have used. I suggest authors to reform the part of environmental assessment in order to be compliant with an ISO based methodology. Otherwise they should change it with the statement like “ A LCA approach was used only considering one year data to evaluate the difference…”

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

1^st Reviewer -2^nd Review

1. Title & Abstracts

Abstract: You must mention the one year data evaluation of the compared systems

 

Introduction:

General comment: Still very general and narrative. Not quite compatible with the title as you changed it now. You should refer other similar studies that compare sustainability.

 

Material and Methods:

2.2. Environmental Assessment:

Initially, it is clear that you followed a LCA approach based on ISO standards regarding specific elements like FU, system boundary, impact assessment.

Still some points need to be justified. In general, all the questions here were made in order to help you make the material and methods part more complete. The answers should be included in the manuscript not only in author response document.

1. Why using a mass-based FU (Line 88)? You answered in the response table: “We think area(ha) based FU is affected by climate condition.” What do you mean? is not very clear. If you search in literature you will find the answer why agricultural LCA use mainly mass based FU!
2. Primary and secondary data: In line 98-100 you added that primary data were less that five years. How many years? This is also opposite to previous version where you said that only one-year data you used!
3. What about the emissions during supply chain of all inputs (not only emissions during pear growing)? You answered in author response but you should also mention in the manuscript.
4. Line 90-92 : Since you evaluate LCA of a perennial cultivation you should justify why you exclude some parts of the production stages from system boundary like, nursery process and planting, or why you only consider one production year into evaluation! You must highlight that you consider only one year and justify it also. Additionally, in figure 1 you include wastewater treatment that in 142-144 you mention that are excluded and in the response table you say: “See revised figure 1”. I think the figure is not revised
5. Carbon dioxide uptake considered? In line 94 of manuscript you refer that you exclude CO2 uptake assuming that the two types of farms of cultivation were the same (concerning what? Because if they are the same why you compared them?) and in the response table you refer that “ This manuscript don’t consider CO2 uptake because CO2 uptake is outside of the scope of Korea low-carbon certification.” What this means? In LCA you should consider all the substances flows and not exclude a part of a flow because it does not suit to the study. CO2 uptake is not considered to LCA studies due to another reason that you will find if you look into literature!
6. Human labor? In line 96 of manuscript you refer that you exclude human labor and in your response table you say “In general, LCA don’t consider human labor.” Of course this is not the right approach. You should justify why in most LCAs human labor is not included, based again on literature!
7. What about time boundary? In author response you answered: “In general, Time boundary of primary data is one year in accordance with ISO 14044. The reason for collecting data for one year is to eliminate the seasonal effect”. I believe you have misunderstood what ISO recommends. I would like to indicate where this is referred. Ideally for one year crops the average of 3-4 year of data provide a good quality of data. Databases of secondary data are developed in a similar way. Regarding perennial crops like fruit crops, the whole life cycle ideally should be considered from nursery and planting of seedlings to the end of tree life. However, little studies performed such analysis. Most studies evaluate more that one year the environmental impact in order to have more accurate data.
8. What modelling approach did you used? The answer should be included in the manuscript
9. Direct and indirect emissions’ calculation (based on which guidelines) should be mentioned in the manuscript
10. Line 117-118 : It should be deleted since nowhere else in the manuscript water footprint is analyzed. Likewise for CF

 

Results and Discussion

Line 142-144: You refer “emissions and 142 wastes generated during the cultivation process were excluded from the scope of data collection in 143 this study because they are not managed by farmers.” What do you mean by that? How did you perform the Impact assessment without including the emissions from the use phase of inputs? This is a methodology flaw.

Line 147-148: it is not clear what you are saying. You assumed the yield from the two methods is the same, meaning that the data collected are not corresponded to that amount of yield?

Line155: “thus” is the correct word? The meaning is not clear

Line 161: How did you use these data set? Did you adjust to Korean conditions?

Line 163-164: A data quality analysis should be performed

Line 183: Not only CO2 is responsible for climate change, but other GHGs.You should take into account the other emissions and make the graph again having as unit CO2 eq

Line 197-198: Why paper cover cause higher NMVOC? Explain. Also do you mean by apple paper cover, the fruit bagging technique? If yes you should make it more clear that it is a technique.

231-232: Explain why toxic effect of in low-carbon farming was higher

252: In Table 6 the last column is missing (not referring to last row as you say in author response)

Table 7: check the table; Maintenance ratio. Not revised in my document

General Comment: The section needs to be corrected again in some points. Some methodological flaws need to be considered. Many points in this section are not comprehensive; No references on similar published research is included. The economic analysis is quite well presented.

Also, you should not start a sentence with “And” or with amount (number).

Conclusion

The conclusion supports the subject of the article, but also, they are too narrative

NOVELTY, LIMITATION AND ADDITIONAL SUGGESTION

I noticed some methodological inconsistencies that need to be changed. E.g. exclusion of emissions in the use phase could be the reason for non-precise results. I suggest authors to revise the environmental part of the manuscript.

 

Author Response

Please find the attached file

Author Response File: Author Response.pdf