Fungicide Cost Reduction with Soybean Rust-Resistant Cultivars in Paraguay: A Supply and Demand Approach

Round 1

Reviewer 1 Report

The submitted manuscript is interesting and addresses extremely important and current issues. However, I suggest to make a few additions and corrections, which are listed below.

The Introduction chapter is quite general, I propose to expand it in order to better introduce potential readers to the described issue. The article lacks reference to the concept of sustainable development, and due to both the title and scope of the journal, it is advisable. This can be included in the Introduction, for example.

The Discussion chapter is rather an extension of the Results chapter. The Sustainability journal has an international scope, so it would be good to relate the research results to the results and reports of other researchers, including authors from other countries. Unfortunately, this chapter lacks a broader discussion of the research results obtained.

In my opinion, the Conclusions chapter should also be improved and supplemented. What research and utilitarian gaps are to be filled by the submitted manuscript? Who can benefit from the results of these studies, etc.?

Author Response

Response to Reviewer 1 Comments

Thank you very much for your thoughtful and constructive feedback regarding our manuscript. We have revised our manuscript accordingly. We provide a point-by-point response to the questions and comments below.

 

Point1:

The Introduction chapter is quite general, I propose to expand it in order to better introduce potential readers to the described issue. The article lacks reference to the concept of sustainable development, and due to both the title and scope of the journal, it is advisable. This can be included in the Introduction, for example.

• We added the explanations about environmental aspects in the Introduction section on page 2, lines 65-73. The discussion section also revised adding environmental risks with many references on page 12, lines 292-313.

In the Introduction section, we added as follows:

Fungicides are used by most farmers worldwide although their use can precipitate soil and water pollution and possibly alter the aquatic biota [14]. The risks of pesticides use have historically been focused on insecticides [15-17] and less so on fungicides [14, 18]. Because fungicides are generally lipophilic, they might absorb sediments as organic carbon and persist on the water surface [19, 20]. Despite the risks, no academic research has been conducted examining the potential risk of environmental pollution associated with the use of pesticides to address SBR in Paraguay. Most previous research has focused on the effectiveness of agricultural fungicides in maintaining crop yields [21, 22]. In the present study, the influence of SBR-resistant cultivar propagation on the environment, especially aquatic ecosystems, was evaluated in terms of fungicide use in Paraguay.

In the Discussion section, we added as follows:

Using pesticides has polluted the soil and aquatic ecosystems as well as decreased water quality in Paraguay [41]. However, most previous reports have analyzed insecticides [15-17] rather than fungicides [e.g. 14]. Because most fungicides are lipophilic and therefore highly mobile in the soil and water matrix as well as persistent in water, they have polluted the soil, decreased water quality and negatively affected organisms in aquatic environments globally [14]. While laboratory-based research has been conducted to investigate the risks to organisms, Ochoa-Acuña et al. [42] demonstrated that the SBR fungicides might affect microorganisms such as algae and zooplankton in the midwestern United States. In Table 7, the fungicides used for soybean cultivation in Paraguay and the organisms can be affected by them are listed. There have been reports that fungicides have polluted the environment of Paraguay, although, the fungicide groups that have been used in Paraguay should be detected in the environment. The most toxic fungicide used in Paraguay is tebuconazole, which inhibits the respiration and photosynthesis of plankton communities at a low concentration, 2 ug L⁻¹ [43]. Azoxystrobin also has negative effects at the lower concentration of 3.3 ug L⁻¹ and can trigger changes in zooplankton population composition [44]. Due to the fact that the half-lives of those fungicides are similar to other pesticides [14], the increasing application of such fungicides to address SBR will seriously influence Paraguay’s environment. Therefore, adopting SBR-resistant cultivars can lessen the negative influence of fungicides in addition to providing cost savings. Due to the lack of reports on environmental risk based on field surveys in Paraguay, additional research will be needed in the future.

 

Point2:

The Discussion chapter is rather an extension of the Results chapter. The Sustainability journal has an international scope, so it would be good to relate the research results to the results and reports of other researchers, including authors from other countries. Unfortunately, this chapter lacks a broader discussion of the research results obtained.

• We revised the discussion section according to the comments on page 11, lines 266-278 as follows:

What can be inferred from the fungicide reduction afforded by the introduction of these cultivars? There is a significant difference in not only the planted area according to country area but also in farm size has between Paraguay and Brazil. Approximately 72% of farmers’ cultivation areas are smaller than 50 ha in Paraguay [33], while only 7.1% of all farmers are peasants (i.e. have farms smaller than 10 ha) in the central western region, which included the highest-ranked producer state, Mato Grosso, Brazil, in 2008 [35]. The cost savings of SBR-resistant cultivar adoption for a 60.9% dissemination rate in the planted area can be estimated at 1.28 billion USD for all of Brazil in 2030 [6]. In spite of the huge amount of cost savings in Brazil, the benefit of the cost reduction might trigger  the development of an economic disparity between farmers, since typical soybean farm size is 1,300 ha in Mato Grosso, according to Osaki and Batalha [36]. If small farmers in Paraguay adopt SBR-resistant cultivates and thereby reduce their production costs, the cost savings benefits will extend to many farmers. From this perspective, spreading these cultivars has the potential to improve many farmers’ profits in Paraguay.

 

Point3:

In my opinion, the Conclusions chapter should also be improved and supplemented. What research and utilitarian gaps are to be filled by the submitted manuscript? Who can benefit from the results of these studies, etc.?

• We included the utilitarian gaps, beneficial for the results in the Conclusion section on page 13, lines 328-341.

In terms of the possible limitations of the present study, the following issues should be tackled. First, the actual yield data for SBR-resistant cultivars that are unclear might possibly alter our estimations. Second, other diseases such as charcoal rot should be considered due to their economic importance. To cope with such issues, the actual yield data for these cultivars and the effects of fungicides on charcoal rot should be considered in future research.

In addition to lessening farmers’ financial burden, adopting SBR-resistant cultivars might reduce environmental pollution to areas such as aquatic biota. However, research investigating the effects of fungicides on Paraguay’s environment has not yet been conducted. Further research is needed to demonstrate the reduction in the environmental load of SBR-resistant cultivars in situ. The present research demonstrated the cost savings afforded by the dissemination of SBR-resistant cultivars and estimated the resulting reduction in environmental pollution in Paraguay. The adoption of such cultivars is required to develop sustainable agriculture in Paraguay and establish a stable global market for soybeans.

 

Author Response File: Author Response.pdf

Reviewer 2 Report

It is an interesting manuscript. As the authors state (lines 54-59), the objective of the paper is to investigate the effect of soybean rust - resistant cultivars on the soybean market and cost reduction of soybean production in Paraguay. They also compare the chemical costs among other main soybean-producing countries and discuss the effect of introducing soybean rust – resistant cultivars.

- I suggest authors to make more coherent the aim of the study and better clear the research goals of the manuscript. They should also highlight the originality of the manuscript in combination with their contribution to the field.

- Apart from the impact of the adoption of the rust - resistant cultivars on the cost, the authors should report the environmental benefits of the adoption of the resistant cultivars as well as the market - related effects. For example, they should highlight the positive and negative effects on the soybean demand which are attributed to the product quality or/and genetic modification as well as to price specific issues.

- There is no a sufficient discussion of the results of the present research in comparison with the results of analogous previously published studies, e.g. Ishiwata, Y.I.; Furuya, J. Evaluating the Contribution of Soybean Rust- Resistant Cultivars to Soybean Production and the Soybean Market in Brazil: A Supply and Demand Model Analysis. Sustainability 2020, 12, 1422.

- The authors should substantially rework the conclusion section. They should give some generalizations and limitations of the study, while they should add also propositions for future research as well as implications for the market participants including farmers and for the public authorities.

- Because some grammatical mistakes there exist, a language editing should be conducted. The authors should also thing to replace the term “department” they use with another term e.g. district, area, region, place, county, etc...

- In addition to the above, the authors could enhance the value of the paper if they make it more friendly to the reader and the audience of the journal. For example, they could properly adapt the figures in order these to become more concise/comprehensive.

The authors should properly rework the manuscript taking into consideration the above noted comments.

Author Response

Response to Reviewer 2 Comments

Thank you very much for your thoughtful and constructive feedback regarding our manuscript. We have revised our manuscript accordingly. We provide a point-by-point response to the questions and comments below.

 

Point1:

- I suggest authors to make more coherent the aim of the study and better clear the research goals of the manuscript. They should also highlight the originality of the manuscript in combination with their contribution to the field.

Thank you very much for your thoughtful comments. According to your comment, we added more explanation and originally of the present study in the Introduction section on page 2, lines 62-82 with raising several questions to highlight the originality of this research and also for the Conclusion sections on page 13, lines 334-341.

In the Introduction section, we added as follows:

We also discussed the potential economic benefits for small farmers in Paraguay through a comparison with the Brazilian case.

Fungicides are used by most farmers worldwide although their use can precipitate soil and water pollution and possibly alter the aquatic biota [14]. The risks of pesticides use have historically been focused on insecticides [15-17] and less so on fungicides [14, 18]. Because fungicides are generally lipophilic, they might absorb sediments as organic carbon and persist on the water surface [19, 20]. Despite the risks, no academic research has been conducted examining the potential risk of environmental pollution associated with the use of pesticides to address SBR in Paraguay. Most previous research has focused on the effectiveness of agricultural fungicides in maintaining crop yields [21, 22]. In the present study, the influence of SBR-resistant cultivar propagation on the environment, especially aquatic ecosystems, was evaluated in terms of fungicide use in Paraguay.

In this study, we address the following five questions:

• How much damage does SBR impose on soybean production in Paraguay?
• To what extent can SBR-resistant cultivars alleviate the soybean production problems caused by SBR-related damage?
• How much cost savings are created by the use of SBR-resistant cultivars?
• Who will benefit from the adoption of SBR-resistant cultivars?
• What are the possible effects of SBR-resistant cultivar dissemination on Paraguay’s environment?

The limitations of this research also considered and discussed in the concluding remarks.

In the Conclusion section, we added as follows:

In addition to lessening farmers’ financial burden, adopting SBR-resistant cultivars might reduce environmental pollution to areas such as aquatic biota. However, research investigating the effects of fungicides on Paraguay’s environment has not yet been conducted. Further research is needed to demonstrate the reduction in the environmental load of SBR-resistant cultivars in situ. The present research demonstrated the cost savings afforded by the dissemination of SBR-resistant cultivars and estimated the resulting reduction in environmental pollution in Paraguay. The adoption of such cultivars is required to develop sustainable agriculture in Paraguay and establish a stable global market for soybeans.

 

Point2:

- Apart from the impact of the adoption of the rust - resistant cultivars on the cost, the authors should report the environmental benefits of the adoption of the resistant cultivars as well as the market - related effects. For example, they should highlight the positive and negative effects on the soybean demand which are attributed to the product quality or/and genetic modification as well as to price specific issues.

Thank you very much for the thoughtful comment. We included the effect of the environment in the last part of the Discussion section on page 12, lines 292-313 with Table 7.

Using pesticides has polluted the soil and aquatic ecosystems as well as decreased water quality in Paraguay [41]. However, most previous reports have analyzed insecticides [15-17] rather than fungicides [e.g. 14]. Because most fungicides are lipophilic and therefore highly mobile in the soil and water matrix as well as persistent in water, they have polluted the soil, decreased water quality and negatively affected organisms in aquatic environments globally [14]. While laboratory-based research has been conducted to investigate the risks to organisms, Ochoa-Acuña et al. [42] demonstrated that the SBR fungicides might affect microorganisms such as algae and zooplankton in the midwestern United States. In Table 7, the fungicides used for soybean cultivation in Paraguay and the organisms can be affected by them are listed. There have been reports that fungicides have polluted the environment of Paraguay, although, the fungicide groups that have been used in Paraguay should be detected in the environment. The most toxic fungicide used in Paraguay is tebuconazole, which inhibits the respiration and photosynthesis of plankton communities at a low concentration, 2 ug L⁻¹ [43]. Azoxystrobin also has negative effects at the lower concentration of 3.3 ug L⁻¹ and can trigger changes in zooplankton population composition [44]. Due to the fact that the half-lives of those fungicides are similar to other pesticides [14], the increasing application of such fungicides to address SBR will seriously influence Paraguay’s environment. Therefore, adopting SBR-resistant cultivars can lessen the negative influence of fungicides in addition to providing cost savings. Due to the lack of reports on environmental risk based on field surveys in Paraguay, additional research will be needed in the future.

 

Point3:

- There is no a sufficient discussion of the results of the present research in comparison with the results of analogous previously published studies, e.g. Ishiwata, Y.I.; Furuya, J. Evaluating the Contribution of Soybean Rust- Resistant Cultivars to Soybean Production and the Soybean Market in Brazil: A Supply and Demand Model Analysis. Sustainability 2020, 12, 1422.

We compared with our previous results about this issue in Brazil in the discussion section on page11, lines 266-278.

What can be inferred from the fungicide reduction afforded by the introduction of these cultivars? There is a significant difference in not only the planted area according to country area but also in farm size has between Paraguay and Brazil. Approximately 72% of farmers’ cultivation areas are smaller than 50 ha in Paraguay [33], while only 7.1% of all farmers are peasants (i.e. have farms smaller than 10 ha) in the central western region, which included the highest-ranked producer state, Mato Grosso, Brazil, in 2008 [35]. The cost savings of SBR-resistant cultivar adoption for a 60.9% dissemination rate in the planted area can be estimated at 1.28 billion USD for all of Brazil in 2030 [6]. In spite of the huge amount of cost savings in Brazil, the benefit of the cost reduction might trigger the development of an economic disparity between farmers, since typical soybean farm size is 1,300 ha in Mato Grosso, according to Osaki and Batalha [36]. If small farmers in Paraguay adopt SBR-resistant cultivates and thereby reduce their production costs, the cost savings benefits will extend to many farmers. From this perspective, spreading these cultivars has the potential to improve many farmers’ profits in Paraguay.

 

Point4:

- The authors should substantially rework the conclusion section. They should give some generalizations and limitations of the study, while they should add also propositions for future research as well as implications for the market participants including farmers and for the public authorities.

We revised our Conclusion section according to your comments. We added remarks about limitations and propositions in the conclusion section on page 13, lines 328-341.

In terms of the possible limitations of the present study, the following issues should be tackled. First, the actual yield data for SBR-resistant cultivars that are unclear might possibly alter our estimations. Second, other diseases such as charcoal rot should be considered due to their economic importance. To cope with such issues, the actual yield data for these cultivars and the effects of fungicides on charcoal rot should be considered in future research.

In addition to lessening farmers’ financial burden, adopting SBR-resistant cultivars might reduce environmental pollution to areas such as aquatic biota. However, research investigating the effects of fungicides on Paraguay’s environment has not yet been conducted. Further research is needed to demonstrate the reduction in the environmental load of SBR-resistant cultivars in situ. The present research demonstrated the cost savings afforded by the dissemination of SBR-resistant cultivars and estimated the resulting reduction in environmental pollution in Paraguay. The adoption of such cultivars is required to develop sustainable agriculture in Paraguay and establish a stable global market for soybeans.

 

Point5:

- Because some grammatical mistakes there exist, a language editing should be conducted. The authors should also thing to replace the term “department” they use with another term e.g. district, area, region, place, county, etc...

Our manuscript has been checked by a language editing company before submitting this revised manuscript.

 

Point6:

- In addition to the above, the authors could enhance the value of the paper if they make it more friendly to the reader and the audience of the journal. For example, they could properly adapt the figures in order these to become more concise/comprehensive.

We included the Figure 2 (page 6) to familiarize the readers.

 

The authors should properly rework the manuscript taking into consideration the above noted comments.

Thank you very much for your insightful comments.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

I would like to thank the Authors for addressing my suggestions and providing explanations. In my opinion, the manuscript has been improved and is suitable for publication.