Environmental Impacts of Rice Intensification Using High-Yielding Varieties: Evidence from Mazandaran, Iran

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

It is important to understand how to obtain consistency of objectives and conclusions from each of the findings and data. The content of this manuscript seems somewhat different from the nature of this journal.

Comments on the Quality of English Language

I don't have any commnents on quality of English.

Author Response

Reviewer#1

Dear Reviewer

Thank you for reading this submission and for delivering suggestions for improvement. Please find below a description of the way how your requests for revisions were addressed.

 

It is important to understand how to obtain consistency of objectives and conclusions from each of the findings and data.

The conclusions section was revised to link better to study objectives.

Lines 791-831: “This study compares the life cycle environmental impacts of the cultivation of traditional rice varieties vs. high-yielding rice varieties on a per yield and per area basis, to show the potential contribution of variety selection to sustainable rice intensification. The case study is a specialised rice producing region in northern Iran (Qaemshahr, Mazandaran Province). Based on a comparative Life Cycle Assessment of real-world paddy farming, the study quantifies area- and yield-scaled impacts, analyses hotspots and highlights trade offs.

Findings show that HRV (Shiroodi, Neda) could significantly reduce critical environmental impacts per t paddy yield, compared to TRV (Tarom Hashemi), such as global warming potential (-28%), ozone formation, human health, and terrestrial ecosystems, (-29%), fossil resource scarcity (-26%). However, the trend is reverted when area-scaled impacts are considered, e.g., global warming potential (+13%), terrestrial acidification (+47%), marine eutrophication (+59%), fossil resource scarcity (+15%) per ha. This trade-off might be unavoidable to meet the greater demand for production inputs of HRV to achieve higher yields. HYV increased pesticide use per ha and per t, with no agronomic reason behind that, with greater toxicity impacts.

Hotspot analysis points to human and ecosystem toxicity, freshwater eutrophication, terrestrial acidification, and fossil resource scarcity as the most alarming impacts of paddy production. Those impacts are generated through the consumption of pesticides, nitrogen fertilizers, and electricity for water pumping. Under current management conditions, replacing TRV with HRV can exacerbate those impacts at the territorial level.

Taken together, research findings call for an urgent improvement of farming practices and especially crop protection patterns. Encouraging a shift to HRV is not enough to enable a transition to sustainable food production. Education and advisory services should be boosted to promote a wide adoption of variety-specific best management practices, as well as awareness about optimal pesticide use, thereby avoiding heuristics. The design of future agro-environmental policies should carefully consider the trade-offs between area-scaled and yield-scaled impacts to find the best balance between the need for sustainable food security and local environmental impacts. Special attention should be paid to environmental hotspots that have the potential to exponentially increase the risks for human and ecosystem health in the future.

The lessons learnt from this study should be helpful in further research about rice intensification. However, some study limitations should be considered, such as the small sample size and the lack of a counterfactual. Extending the study to a broader set of farms would enable the identification of cause-effect relationships between input data and impact assessment results. A counterfactual analysis would help to understand the extent to which study findings depend on the specific characteristics of the surveyed farms, e.g., by comparing the same group of farms before and after adopting high-yield varieties. Linking the environmental assessment with the analysis of farm household variables may improve the understanding of the impact of demographic and social factors on farm management. Given the significant impact of pesticides, more qualitative research is needed about pesticide use, especially to understand the barriers and drivers to adopting sustainable pest and weed control methods.”

 

The content of this manuscript seems somewhat different from the nature of this journal.

The revised introduction, including the reference to SDGs links more directly to the aims and scope of the journal Sustainability, as well a subject areas (e.g. System analysis methods, including life cycle assessment and management, …):

Lines 43-51: “Understanding how to improve the sustainability and food security outcomes of staple crop production within planetary boundaries is paramount [1,2]. This is a global challenge especially hotspot regions, severely affected by climate change and the overexploitation of natural resources, and in developing countries characterised by high population growth rates [3]. The urgency of addressing these challenges is reflected by United Nations’ Sustainable Development Goals, i.e. goals 2 (zero hunger), 3 (good health and well-being), 6 (clean water and sanitation), 12 (responsible production and consumption), 13 (climate action), 14 (life below water), 15 (life on land) [4].”

Lines 72-75: “Against that background, this study aims to compare the life cycle environmental impacts of the cultivation of TRV vs. HRV on a per yield and per area basis, by providing evidence from real-world paddy farming in Iran. The research method is life cycle assessment (LCA; ISO 14040:2006, 14044:2006).”

Reviewer 2 Report

Comments and Suggestions for Authors

1.Relevant frontier reviews in the research background can be quoted appropriately to indicate or predict the future research direction.

2.The unit expression of the full text of the article can be unified, and "per year" or "/"can be used uniformly.

3.In the discussion part, please cite the achievements in the last five years as much as possible to explain and prove. If there are any articles in the top journals, please quote them as much as possible.

 

Comments on the Quality of English Language

Attention should be paid to academic rigor in English expression

Author Response

Reviewer#2

Dear Reviewer

Thank you for your suggestions to improve the manuscript. Please find below point-by-point replies to your comments.

 

1.Relevant frontier reviews in the research background can be quoted appropriately to indicate or predict the future research direction.

In the revised introduction, the following frontier reviews were cited:

[1] Campbell, B.M.; Beare, D.J.; Bennett, E.M.; Hall-Spencer, J.M.; Ingram, J.S.I.; Jaramillo, F.; Ortiz, R.; Ramankutty, N.; Sayer, J.A.; Shindell, D. Agriculture Production as a Major Driver of the Earth System Exceeding Planetary Boundaries. Ecology and Society 2017, 22, art8, doi:10.5751/ES-09595-220408.

[2] Richardson, K.; Steffen, W.; Lucht, W.; Bendtsen, J.; Cornell, S.E.; Donges, J.F.; Drüke, M.; Fetzer, I.; Bala, G.; Von Bloh, W.; et al. Earth beyond Six of Nine Planetary Boundaries. Sci. Adv. 2023, 9, eadh2458, doi:10.1126/sciadv.adh2458.

[3] Gerten, D.; Heck, V.; Jägermeyr, J.; Bodirsky, B.L.; Fetzer, I.; Jalava, M.; Kummu, M.; Lucht, W.; Rockström, J.; Schaphoff, S.; et al. Feeding Ten Billion People Is Possible within Four Terrestrial Planetary Boundaries. Nat Sustain 2020, 3, 200–208, doi:10.1038/s41893-019-0465-1.

[58] Mendonça, L.A.; Loomis, J.J.; Limont, M.; Bartz, M.L.C.; Rauen, W.B. Elements of the Water - Food - Environment Nexus for Integrated Sustainability Analysis. Science of The Total Environment 2023, 905, 166866, doi:10.1016/j.scitotenv.2023.166866.

Lines 43-51: “Understanding how to improve the sustainability and food security outcomes of staple crop production within planetary boundaries is paramount [1,2]. This is a global challenge especially hotspot regions, severely affected by climate change and the overexploitation of natural resources, and in developing countries characterised by high population growth rates [3].”

Lines 159-165: “Research findings feed into the science-policy-practice dialogue to foster the diffusion of sustainable intensification, by supporting the creation of synergies between scientific evidence, the design of targeted policy instruments and the conscious adoption of farming practices on the ground [58]. This would contribute to the creation of the socio-economic conditions for enabling crop management changes at the territorial level, towards agricultural resilience and local population’s wellbeing [3,59].”

 

2.The unit expression of the full text of the article can be unified, and "per year" or "/"can be used uniformly.

The ms was double checked for units of measure’s uniformity and “per year” was replaced with “/year”.

 

3.In the discussion part, please cite the achievements in the last five years as much as possible to explain and prove. If there are any articles in the top journals, please quote them as much as possible.

In the discussion section, we tried to expand the reference to the most recent research achievements. 22 out of 38 references cited in the discussion and (new) recommendations section were published after 2019, most of which in top ranked journals. The following references were added during this review round:

 

Bakhshandeh, E.; Jamali, M.; Emadi, M.; Francaviglia, R. Greenhouse Gas Emissions and Financial Analysis of Rice Paddy Production Scenarios in Northern Iran. Agricultural Water Management 2022, 272, 107863, doi:10.1016/j.agwat.2022.107863.

 

Fan, J.; Liu, C.; Xie, J.; Han, L.; Zhang, C.; Guo, D.; Niu, J.; Jin, H.; McConkey, B.G. Life Cycle Assessment on Agricultural Production: A Mini Review on Methodology, Application, and Challenges. International Journal of Environmental Research and Public Health 2022, 19, 9817, doi:10.3390/ijerph19169817.

 

Jamali, M.; Bakhshandeh, E.; Emadi, M. Effects of Water Source and Technology on Energy Use and Environmental Impacts of Rice Production in Northern Iran. Water Resources Research 2022, 58, e2021WR031546, doi:10.1029/2021WR031546.

 

Islam Bhuiyan, M.S.; Rahman, A.; Kim, G.W.; Das, S.; Kim, P.J. Eco-Friendly Yield-Scaled Global Warming Potential Assists to Determine the Right Rate of Nitrogen in Rice System: A Systematic Literature Review. Environmental Pollution 2021, 271, 116386, doi:10.1016/j.envpol.2020.116386.

 

Wang, H.; Zhang, Y.; Zhang, Y.; McDaniel, M.D.; Sun, L.; Su, W.; Fan, X.; Liu, S.; Xiao, X. Water-Saving Irrigation Is a ‘Win-Win’ Management Strategy in Rice Paddies – With Both Reduced Greenhouse Gas Emissions and Enhanced Water Use Efficiency. Agricultural Water Management 2020, 228, 105889, doi:10.1016/j.agwat.2019.105889.

Reviewer 3 Report

Comments and Suggestions for Authors

Thank you for considering me to review the manuscript titled “Impacts of rice intensification through high-yielding varieties. Evidence from Mazandaran, Iran”. The manuscript is well-written and well-structured and could be accepted after revisions.

Suggestions:

English language editing is necessary throughout the manuscript to rectify grammatical errors and shorten lengthy sentences.

The title needs to be improved to "Impacts of Rice Intensification Using High-Yielding Varieties: Evidence from Mazandaran, Iran".

The study importance should be highlighted at the beginning of the abstract. Also, please improve the abstract to be more descriptive by providing additional more details on collected data and emphasizing the obtained results.

Keywords, more relevant keywords should be added and should be ordered alphabetically

The introduction needs to be improved and organized. The knowledge gap and hypothesis need to be elucidated more thoroughly, the objectives should be extended and clarified.

Please provide the specific abbreviation used in Figure 4 and its corresponding complete name in the figure title.

The used units should be revised and unified throughout the manuscript.

The discussion needs to be improved and include recent literature with clarification of ambiguous statements.

 

It is vital to follow the journal style guide for uniformity and accuracy. Review and standardize the reference section according to journal style guidelines. 

Comments for author File: Comments.pdf

Comments on the Quality of English Language

Moderate editing of English language required

Author Response

Reviewer#3

Dear Reviewer

Thank you very much for the detailed comments. Please find below point-by-point replies to all your suggestions. Please note that we considered the more detailed version of your suggestions, available as a pdf attachment of your peer review report. We did not provide the revised text here for the sake of readability of this letter.

 

1. Ensure thorough English language editing throughout the manuscript to rectify

grammatical errors and shorten lengthy sentences.

English language was double checked, readability improved (especially with respect to long sentences) and mistakes corrected throughout the ms text.

 

2. Improve and organize the introduction by elaborating on the knowledge gap, hypothesis,

and extending and clarifying the objectives.

The introduction was reorganised to improve the logical flow of information, to provide a better specification of study objectives, to highlight research gaps, and to show how this research advance knowledge.

 

3. Clarify how the environmental impact differs between traditional and high-yielding

varieties when considering both area-based and yield-based results.

Statistically significant differences are calculated for the two variety groups for both functional units and major differences highlighted and presented in the ms text.

 

4. Clearly distinguish between the cultivation practices of traditional and high-yielding

varieties, emphasizing key environmental implications and potential trade-offs.

Cultivation practices are briefly presented in the ms and relevant literature quoted. Farm survey highlighted that farming practice did not differ between the two variety groups. This finding was discussed and related recommendations provided.

 

5. Provide more details about the case study area, including longitude, latitude, soil analysis,

and meteorological data, to enhance the contextual understanding.

An improved description for the case study area is available from section 2.1, including a map as well.

 

6. Elaborate on cultivation practices, including inputs such as seeds, fertilizers, pesticides,

energy use, water consumption, and machinery usage for a comprehensive assessment.

Cultivation practices are briefly presented in the ms and relevant literature quoted. Survey data about the actual consumption of production inputs are provided in table 1 and statistically analysed in section 3.1 on a per area and per yield basis for the two variety groups.

 

7. Utilize appropriate impact assessment methods to quantify and evaluate direct and

indirect environmental impacts associated with each rice cultivation method.

8. Provide more clarification on relevant environmental impact categories, including

greenhouse gas emissions, land use, water use, and energy consumption.

An improved description of impact assessment methods is available from section 2.2.3 and the relevant literature is quoted for reader reference, including modelling parameters and details.

 

9. Clarify the characteristics and traits of high-yielding varieties contributing to their

increased yield per unit area, emphasizing features like disease resistance, pest resistance,

or shorter growing periods.

Key characteristics of the analysed rice cultivars are provided.

 

10. Explore factors contributing to the overall increase in environmental impacts per hectare

despite reduced impacts per ton of paddy yield. Discuss potential trade-offs associated

with intensified agricultural practices.

Hotspot analysis shows the contribution to impacts of life cycle stages and unit processes. The trade-offs associated with the adoption of high-yielding varieties are discussed.

 

11. Break down the analysis by impact categories e.g., greenhouse gas emissions, land use,

water use to provide specific observations for each category.

Major impact categories and hotspots are discussed, to focus on how to deliver meaningful recommendations on priority objectives for ensuring food security while considering environmental outcomes.

 

12. Sensitivity analyses could be employed to assess the influence of key parameters or

uncertainties on the results for a more robust analysis.

A sensitivity analysis is added in the methods section (2.2.4) and in the results section (3.4), by changing the cultural perspective in the impact assessment method, which includes offering a wider range of time horizons (see also the explanation in section 2.3).

 

13. Enhance recommendations for sustainable rice cultivation practices based on the obtained results, considering environmental trade-offs.

Practice recommendations with wider applicability beyond the case study level are delivered in the new section 5 (5.2).

 

14. Highlight any nuances or specific conditions in Mazandaran, Iran, that might influence

overall impact patterns.

An improved description of impact assessment methods is available from section 2.2.3 and the relevant literature is quoted for reader reference, including modelling parameters and details.

 

15. Revise and unify the units used throughout the manuscript for consistency.

The ms and tables was double checked for units of measure’s uniformity.

 

16. Specify the abbreviation used in Figure 4 and provide its corresponding complete name

in the figure title.

A better specification of acronyms was added to table 3. Acronym explanation was added to the caption of figures/tables when needed, as footnotes are not allowed by the journal.

Example of caption: “GWP= Global warming potential; OD= Ozone depletion; IR= Ionizing radiation; OF-hh= Photochemical oxidant formation: human health; PM= Fine particulate matter formation (PM); OF-te= Photochemical oxidant formation: terrestrial ecosystems (OF-te); AC= Terrestrial acidification (AC); FE= Freshwater eutrophication; ME= Marine eutrophication; TET= Terrestrial ecotoxicity; FET= Freshwater ecotoxicity; MET= Marine ecotoxicity (MET); HCT= Human toxicity: cancer (HCT); HnCT= Human toxicity: non-cancer (HnCT); LU= Land use; MRS= Mineral resource scarcity; Fossil resource scarcity (FRS)”

 

17. Consider regional variations in impact patterns and discuss how local conditions, climate,

and management practices may influence the observed results.

An improved description of impact assessment methods is available from section 2.2.3 and the relevant literature is quoted for reader reference, including modelling parameters and details.

 

18. Discuss whether the observed increase in overall impact per hectare is a temporary effect during a transition period or a long-term consequence of high-yielding varieties adoption.

A sensitivity analysis is added in the methods section (2.2.4) and in the results section (3.4), by changing the cultural perspective in the impact assessment method, which includes offering a wider range of time horizons (see also the explanation in section 2.3).

 

19. Discuss potential policy implications for sustainable agriculture, considering the

identified trade-offs, and propose mitigation strategies or best management practices.

20. Propose mitigation strategies to minimize the negative environmental impacts associated

with the observed increase in overall impact per hectare.

21. Provide practical recommendations for sustainable rice cultivation practices based on the

obtained resultds.

Practice and policy recommendations with wider applicability beyond the case study level are delivered in the new section 5 (respectively, 5.2 and 5.3).

 

22. The journal name should be abbreviated according to MDPI style. Review and

standardize the reference section according to the journal style guidelines for uniformity

and accuracy.

The official journal style for the reference manager software (Zotero) was used and journal styles were adjusted manually when needed.

Reviewer 4 Report

Comments and Suggestions for Authors

Dear authors and editor,

This paper is writing up in a professional scientific way. it will be accepted after minor revision.

1. Please improve, make the summary more descriptive by providing additional details about the data collected and emphasizing the results obtained

2.Initially, you select 150 farmers but utilize 49. it is suggest to elaborate the process on which you select just 49 answers.

3.The table 1 is not clear to reader - add min and max values, where only mean value is showed

4. Table 3.add footnotes and describe aberrations GWP, OD,PM...etc

5.The discussion needs to be improved and include recent literature

 

Best regards

Author Response

Reviewer#4

Dear Reviewer

Thank you for your comments. We addressed all of them. Please find below point-by point replies.

 

1. Please improve, make the summary more descriptive by providing additional details about the data collected and emphasizing the results obtained

The abstract was completely revised. More information about data is given and outstanding results are presented with a clearer link with research objectives and implications.

New abstract: “This article aims to show the potential contribution of high-yielding rice varieties to achieve sustainable intensification in paddy farming, by focusing on a developing country. A comparative life cycle assessment of traditional vs. high-yielding varieties is carried out by comparing area-based and yield-based results. Primary data are collected through farm survey (49 farms in the Mazandaran province, Iran; spring 2018). Results highlight that high-yielding varieties can reduce yield-scaled impacts. However, area-scaled impacts are subject to increase for most impact categories. Statistically significant trade-offs involve global warming potential (+13% per ha and -28% per t in high-yielding varieties) and fossil resource depletion (+15% per ha and -26% per t in high-yielding varieties). Pesticide management is the most alarming practice. High-yielding varieties increase pesticide consumption and related toxicity impacts both per t and per ha. This study is a new contribution to the literature by improving and broadening the mainstream productivity perspective of current life cycle assessment research about crop varieties. The lessons learnt from this study suggest that the trade-offs between yield-scaled and area-scaled impacts should be carefully considered by decision makers and policy makers, especially in developing countries that, like Iran, are affected by overexploitation of natural resources. Targeted policy and the development of farmer education and advisory services are needed to create the enabling conditions for farm management changes, including conscious use of production inputs while avoiding heuristics.”

 

2.Initially, you select 150 farmers but utilize 49. it is suggest to elaborate the process on which you select just 49 answers.

More details were provided about the data collection process, to explain how we got to the final sample size.

Lines 280-289: “The survey involved three stages, i.e. questionnaire design by the research team, face-to-face questionnaire administration, and review. Agricultural Jihad’s officers were involved in the survey by taking care of questionnaire administration and supporting their review. The theoretical sample size was identified through the Morgan table [77]. The questionnaires were administered to 150 rice farm households in 4 districts (Khadamat, Koohsaran, Nowkandehkah, Aliabad-e-Tajan) of Qaemshahr. The response rate was 45% (68 farm households). Review meetings with respondents were then organized to cover information gaps and to correct mistakes. Just about 70% respondents participated in the review round, which led to final set of 49 complete questionnaires for analysis, with overall response rate of 33%”

 

3.The table 1 is not clear to reader - add min and max values, where only mean value is showed

Table 1 was revised to add min/max values

Table 1. Overview of the farm sample (49 observations). Summary statistics of yearly data. Source: Authors' elaboration.

Materials/resources	Mean	Min	Max	Notes
Area (ha/farm/year)	1.35	0.2	10	Utilized agricultural area for paddy production
Seed (kg/farm/year)	71.7	13	400	Traditional rice variety = 37 farms High-yielding rice varieties = 12 farms
Water (m3/farm/year)	16,895	2,500	150,000	Pumped water
Electricity (kWh/farm/year)	4,416	654	39,205
Machinery operation (h/farm/year)	20.2	2	200
Diesel (L/farm/year)	287	30	1,750	Diesel mass per unit volume = 0.84 kg/L
Nitrogen fertilizers, chemical (kg/farm/year)	159	9.22	1,383	Urea, Ammonium Sulphate, 15-15-15 NPK, Simple Super Phosphate, Potassium Sulphate
Phosphorous fertilizers, chemical (kg/farm/year)	33.9	0	315
Potassium fertilizers, chemical (kg/farm/year)	75.9	0	826
Poultry manure (kg/farm/year)	9.80	0	200
Polyethylene (kg/farm/year)	1.86	0	17	Packaging (seed, fertilizers, and pesticides); manufacturing: extrusion (bags), injection molding (bottles)
Transport distance (km/farm/year)	37.90	13	171
Insecticides, active ingredients (kg/farm/year)	4.8	0	40	Diazinon 78%, Carboxin 25%, Thiram 25%, Fipronil 6%, Fenitrothion 17%
Fungicides, active ingredients (kg/farm/year)	3.37	0	9.3	Tricyclazole 35%, Propiconazole 31%, Tebuconazole 31%, Trifloxystrobin 31%, Iprodione 9%
Herbicides, active ingredients (kg/farm/year)	0.32	0	1.9	Butachlor 77%, Benzofuran methyl 64%, Oxadiazon 11%, Pretilachlor 7%, 2,4-DB 7%
Paddy rice, marketable  (t/farm/year)	7.53	0.686	78.4	Production loss: 2.14%
Producer price (US$/farm/year)	1,517	191	14,833	1US$ = 185,000 Iranian rial (2018)

 

 

4. Table 3.add footnotes and describe aberrations GWP, OD,PM...etc

A better specification of acronyms was added to table 3. Acronym explanation was added to the caption of figures/tables when needed, as footnotes are not allowed by the journal.

Table 3. Midpoint impact categories used in this study (ReCiPe 2016). Source: Authors’ elaboration, based on [89].

Characterized impact categories (abbreviation)	Unit of measure
Global warming potential (GWP)	kg CO2-eq
Ozone depletion (OD)	kg CFC11-eq
Ionizing radiation (IR)	kBq Co-60-eq
Photochemical oxidant formation: human health (OF-hh)	kg NOx-eq
Fine particulate matter formation (PM)	kg PM2.5-eq
Photochemical oxidant formation: terrestrial ecosystems (OF-te)	kg NOx-eq
Terrestrial acidification (AC)	kg SO2-eq
Freshwater eutrophication (FE)	kg P-eq
Marine eutrophication (ME)	kg N-eq
Terrestrial ecotoxicity (TET)	kg 1,4-DCB
Freshwater ecotoxicity (FET)	kg 1,4-DCB
Marine ecotoxicity (MET)	kg 1,4-DCB
Human toxicity: cancer (HCT)	kg 1,4-DCB
Human toxicity: non-cancer (HnCT)	kg 1,4-DCB
Land use (LU)	m2 x yr annual cropland-eq
Mineral resource scarcity (MRS)	kg Cu-eq
Fossil resource scarcity (FRS)	kg oil-eq

 

Example of caption: “GWP= Global warming potential; OD= Ozone depletion; IR= Ionizing radiation; OF-hh= Photochemical oxidant formation: human health; PM= Fine particulate matter formation (PM); OF-te= Photochemical oxidant formation: terrestrial ecosystems (OF-te); AC= Terrestrial acidification (AC); FE= Freshwater eutrophication; ME= Marine eutrophication; TET= Terrestrial ecotoxicity; FET= Freshwater ecotoxicity; MET= Marine ecotoxicity (MET); HCT= Human toxicity: cancer (HCT); HnCT= Human toxicity: non-cancer (HnCT); LU= Land use; MRS= Mineral resource scarcity; Fossil resource scarcity (FRS)”

 

5.The discussion needs to be improved and include recent literature

The discussion section was improved to focus more on our achievements and their implications (not reported here for the sake of synthesis). Recent references were added as well. 22 out of 38 references cited in the discussion and (new) recommendations section were published after 2019, most of which in top ranked journals. The following references were added during this review round:

 

Bakhshandeh, E.; Jamali, M.; Emadi, M.; Francaviglia, R. Greenhouse Gas Emissions and Financial Analysis of Rice Paddy Production Scenarios in Northern Iran. Agricultural Water Management 2022, 272, 107863, doi:10.1016/j.agwat.2022.107863.

 

Fan, J.; Liu, C.; Xie, J.; Han, L.; Zhang, C.; Guo, D.; Niu, J.; Jin, H.; McConkey, B.G. Life Cycle Assessment on Agricultural Production: A Mini Review on Methodology, Application, and Challenges. International Journal of Environmental Research and Public Health 2022, 19, 9817, doi:10.3390/ijerph19169817.

 

Jamali, M.; Bakhshandeh, E.; Emadi, M. Effects of Water Source and Technology on Energy Use and Environmental Impacts of Rice Production in Northern Iran. Water Resources Research 2022, 58, e2021WR031546, doi:10.1029/2021WR031546.

 

Islam Bhuiyan, M.S.; Rahman, A.; Kim, G.W.; Das, S.; Kim, P.J. Eco-Friendly Yield-Scaled Global Warming Potential Assists to Determine the Right Rate of Nitrogen in Rice System: A Systematic Literature Review. Environmental Pollution 2021, 271, 116386, doi:10.1016/j.envpol.2020.116386.

 

Wang, H.; Zhang, Y.; Zhang, Y.; McDaniel, M.D.; Sun, L.; Su, W.; Fan, X.; Liu, S.; Xiao, X. Water-Saving Irrigation Is a ‘Win-Win’ Management Strategy in Rice Paddies – With Both Reduced Greenhouse Gas Emissions and Enhanced Water Use Efficiency. Agricultural Water Management 2020, 228, 105889, doi:10.1016/j.agwat.2019.105889.

 

It is vital to follow the journal style guide for uniformity and accuracy. Review and standardize the reference section according to journal style guidelines.

The official journal style for the reference manager software (Zotero) was used and journal styles were adjusted manually when needed.

 

Reviewer 5 Report

Comments and Suggestions for Authors

 

Dear Authors.

Article describes the important issue of ensuring of sustainability in rice production. The choice of LCA is proper for such article’s topic and purpose, literature overview is sufficient. Anyway, major corrections and improvements should be done.

1. Consider to change the article’s title. Impact of rice intensification...The question is: impact on what? Add necessary words

2. In table 1:

a) change the unit for yield, and recalculate- if necessary  t=> t/ha

b) add min and max. values, where only mean value is showed.

c) add the exact explanation of fertilizer’s usage unit as well as other materials, is “kg” per ha or per total farm are (total usage in farm)?

3. L.13. soil, instead „soi”

4. Lack of data about Animal manure usage, while in table  2 corrections and calculations for it are shown.

5. L.50. Where is Annex 2? Discussion of the results from Annex 2 should be done in this article.

6. L.150=> change description to Figure 3.

7. Lack of wider discussion of the results.

8. Lack of descriptions (footnotes) of shortcomings under figure, in line L.100 as well as tables: GWP, OD  PM AC, FE, ME, TET, FET, MET LU FRS (besides table 3).

9. In conclusions, mainly findings from research also  should be highlighted.

 Besides that, article is suitable for Sustainability journal.

Author Response

Reviewer#5

Dear Reviewer

Thank you for the useful comments. We addressed all of them to improve the quality of the ms. Please find below our replies.

 

1. Consider to change the article’s title. Impact of rice intensification...The question is: impact on what? Add necessary words

Article title was changed as follows: “Environmental impacts of rice intensification using high-yielding varieties: evidence from Mazandaran, Iran”

 

2. In table 1:

 

1. change the unit for yield, and recalculate- if necessaryt=> t/ha
2. add min and max. values, where only mean value is showed.
3. add the exact explanation of fertilizer’s usage unit as well as other materials, is “kg” per ha or per total farm are (total usage in farm)?

 

Table 1 and its caption were revised to better specify the units of measure and to add min max values

Table 1. Overview of the farm sample (49 observations). Summary statistics of yearly data. Source: Authors' elaboration.

Materials/resources	Mean	Min	Max	Notes
Area (ha/farm/year)	1.35	0.2	10	Utilized agricultural area for paddy production
Seed (kg/farm/year)	71.7	13	400	Traditional rice variety = 37 farms High-yielding rice varieties = 12 farms
Water (m3/farm/year)	16,895	2,500	150,000	Pumped water
Electricity (kWh/farm/year)	4,416	654	39,205
Machinery operation (h/farm/year)	20.2	2	200
Diesel (L/farm/year)	287	30	1,750	Diesel mass per unit volume = 0.84 kg/L
Nitrogen fertilizers, chemical (kg/farm/year)	159	9.22	1,383	Urea, Ammonium Sulphate, 15-15-15 NPK, Simple Super Phosphate, Potassium Sulphate
Phosphorous fertilizers, chemical (kg/farm/year)	33.9	0	315
Potassium fertilizers, chemical (kg/farm/year)	75.9	0	826
Poultry manure (kg/farm/year)	9.80	0	200
Polyethylene (kg/farm/year)	1.86	0	17	Packaging (seed, fertilizers, and pesticides); manufacturing: extrusion (bags), injection molding (bottles)
Transport distance (km/farm/year)	37.90	13	171
Insecticides, active ingredients (kg/farm/year)	4.8	0	40	Diazinon 78%, Carboxin 25%, Thiram 25%, Fipronil 6%, Fenitrothion 17%
Fungicides, active ingredients (kg/farm/year)	3.37	0	9.3	Tricyclazole 35%, Propiconazole 31%, Tebuconazole 31%, Trifloxystrobin 31%, Iprodione 9%
Herbicides, active ingredients (kg/farm/year)	0.32	0	1.9	Butachlor 77%, Benzofuran methyl 64%, Oxadiazon 11%, Pretilachlor 7%, 2,4-DB 7%
Paddy rice, marketable  (t/farm/year)	7.53	0.686	78.4	Production loss: 2.14%
Producer price (US$/farm/year)	1,517	191	14,833	1US$ = 185,000 Iranian rial (2018)

 

3. L.13. soil, instead „soi”

The typo was corrected

 

4. Lack of data about Animal manure usage, while in table 2 corrections and calculations for it are shown.

A line about animal manure was added to table 1. Information about related transportation was added to the main ms text.

Line 319-320: “Poultry manure is self-produced, then no transport is considered.”

The manure variable was not subject to statistical analysis, being used by just three farms.

 

5. L.50. Where is Annex 2? Discussion of the results from Annex 2 should be done in this article.

Thank you for spotting that mistake. Tabled results of the literature review, alongside a concise review method, are presented in the Appendix (not shown here for the sake of synthesis).

 

6. L.150=> change description to Figure 3.

The typo was corrected

 

8. Lack of descriptions (footnotes) of shortcomings under figure, in line L.100 as well as tables: GWP, OD PM AC, FE, ME, TET, FET, MET LU FRS (besides table 3).

Acronym explanation was added to the caption of figures/tables when needed, as footnotes are not allowed by the journal.

Example of caption: “GWP= Global warming potential; OD= Ozone depletion; IR= Ionizing radiation; OF-hh= Photochemical oxidant formation: human health; PM= Fine particulate matter formation (PM); OF-te= Photochemical oxidant formation: terrestrial ecosystems (OF-te); AC= Terrestrial acidification (AC); FE= Freshwater eutrophication; ME= Marine eutrophication; TET= Terrestrial ecotoxicity; FET= Freshwater ecotoxicity; MET= Marine ecotoxicity (MET); HCT= Human toxicity: cancer (HCT); HnCT= Human toxicity: non-cancer (HnCT); LU= Land use; MRS= Mineral resource scarcity; Fossil resource scarcity (FRS)”

 

7. Lack of wider discussion of the results.

The entire discussion section was deeply revised to create a better connection with research objectives and to expand on research implications and recommendations for research, practice and policy (not shown here for the sake of synthesis).

 

9. In conclusions, mainly findings from research also should be highlighted.

The conclusions section was heavily revised. The new conclusions section focuses on the take home messages for the reader and begins with a summary of key research findings.

Lines 791-831: “This study compares the life cycle environmental impacts of the cultivation of traditional rice varieties vs. high-yielding rice varieties on a per yield and per area basis, to show the potential contribution of variety selection to sustainable rice intensification. The case study is a specialised rice producing region in northern Iran (Qaemshahr, Mazandaran Province). Based on a comparative Life Cycle Assessment of real-world paddy farming, the study quantifies area- and yield-scaled impacts, analyses hotspots and highlights trade offs.

Findings show that HRV (Shiroodi, Neda) could significantly reduce critical environmental impacts per t paddy yield, compared to TRV (Tarom Hashemi), such as global warming potential (-28%), ozone formation, human health, and terrestrial ecosystems, (-29%), fossil resource scarcity (-26%). However, the trend is reverted when area-scaled impacts are considered, e.g., global warming potential (+13%), terrestrial acidification (+47%), marine eutrophication (+59%), fossil resource scarcity (+15%) per ha. This trade-off might be unavoidable to meet the greater demand for production inputs of HRV to achieve higher yields. HYV increased pesticide use per ha and per t, with no agronomic reason behind that, with greater toxicity impacts.

Hotspot analysis points to human and ecosystem toxicity, freshwater eutrophication, terrestrial acidification, and fossil resource scarcity as the most alarming impacts of paddy production. Those impacts are generated through the consumption of pesticides, nitrogen fertilizers, and electricity for water pumping. Under current management conditions, replacing TRV with HRV can exacerbate those impacts at the territorial level.

Taken together, research findings call for an urgent improvement of farming practices and especially crop protection patterns. Encouraging a shift to HRV is not enough to enable a transition to sustainable food production. Education and advisory services should be boosted to promote a wide adoption of variety-specific best management practices, as well as awareness about optimal pesticide use, thereby avoiding heuristics. The design of future agro-environmental policies should carefully consider the trade-offs between area-scaled and yield-scaled impacts to find the best balance between the need for sustainable food security and local environmental impacts. Special attention should be paid to environmental hotspots that have the potential to exponentially increase the risks for human and ecosystem health in the future.

The lessons learnt from this study should be helpful in further research about rice intensification. However, some study limitations should be considered, such as the small sample size and the lack of a counterfactual. Extending the study to a broader set of farms would enable the identification of cause-effect relationships between input data and impact assessment results. A counterfactual analysis would help to understand the extent to which study findings depend on the specific characteristics of the surveyed farms, e.g., by comparing the same group of farms before and after adopting high-yield varieties. Linking the environmental assessment with the analysis of farm household variables may improve the understanding of the impact of demographic and social factors on farm management. Given the significant impact of pesticides, more qualitative research is needed about pesticide use, especially to understand the barriers and drivers to adopting sustainable pest and weed control methods.”