Role of Modelling in International Crop Research: Overview and Some Case Studies

Round  1

Reviewer 1 Report

The structure of the paper has greatly improved and so did its readability

I just have some minor (editorial) comments :

Line 85 : direct climate changes… these are not scenarios !

There is a problem with section numbering. Main section’s titles (in bold) seem to be missing for section 5 and 6, as well as some subsections :section 6.1,Section 5.1 and  5.3 do not exist

GxE modeling should be mentioned in the title (current section 5.2 or new section 5.3 ? ) in order to preserve the general structure of the paper

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Author Response

The structure of the paper has greatly improved and so did its readability

Reply: We want to thank the reviewer for acknowledging the work we did in changing the structure and we are glad that its readability has greatly improved.

I just have some minor (editorial) comments :

Line 85 : direct climate changes… these are not scenarios !

Reply: We have addressed the suggested change

There is a problem with section numbering. Main section’s titles (in bold) seem to be missing for section 5 and 6, as well as some subsections :section 6.1,Section 5.1 and  5.3 do not exist

Reply: In the clean version, these sections and subsections appear correctly. Probably the reviewer only checked the under track-changes version, where due to so many changes, these titles might no be so clear. We encourage the reviewer to review the clean manuscript where all the mentioned sections exist.

GxE modeling should be mentioned in the title (current section 5.2 or new section 5.3 ? ) in order to preserve the general structure of the paper

Reply: In the clean version, section 5.3  has the title: “5.3 GxE interactions”, so the general structure is preserved. We encourage the reviewer to review the clean manuscript where all the mentioned sections exist.

Reviewer 2 Report

agronomy-393291

Journal: MDPI- Agronomy

Title: “Role of Modelling in International Crop Research: Overview and some case studies”

Recommendation: major revisions

This paper presents an overview of crop modelling by international crop research at the CGIAR centres. It is an impressive overview. Interesting sections are presented on main development in a number of approaches in the field of crop modelling and related fields. Illustrative case studies are presented. The authors have reviewed and cited an impressive number of 349 publications and provide a large coverage of the field.

Major comments

Authors cite crop models, their history, development and applications for 8 out of 15 CGIAR centres (CIAT, CIMMYT, CIP, ICRAF, ICRISAT, IFPRI, IITA, IRRI). 8 out of 15 is not an overview, it is missing out on almost 50% of the CGIAR centres. An incomplete overview like this gives the false impression that no crop modelling is happening at the other 7 centres. Since these centres work in different domains, the paper automatically also misses out on important developments in crop modelling domains of CGIAR centres not covered in the paper in its current form.  

Below I list important institutes and crop modelling domains that I feel would need to be added to make the paper more complete. In alphabetical order:

1.    AfricaRice: The limited overview in the paper gives the false impression that it is only IRRI working on rice modelling. Substantial contributions to rice modelling have been made at AfricaRice. Here is a short overview

1.1.  1990’s: model improvements on a branch of ORYZA1 called ORYZASAHEL by Dingkuhn et al. A search in Scopus (AFFILORG ( warda )  AND  AUTHOR-NAME ( dingkuhn )) will give you 6 heavily cited papers from this period.

1.2.  2010’s: Model improvements on a branch of ORYZA2000 (AfricaRice version) by van Oort et al. (2015) and van Oort and Zwart ( 2018). Applications in yield gap analysis (van Oort et al 2015, 2017), cropping calendar optimisation (van Oort et al 2016) , GxE modelling in rice hybrids (El-Namaky and van Oort 2017) and climate change impact (van Oort and Zwart 2018).

1.3.  2010’s: Development of smart phone app for fertiliser recommendations  (RiceAdvice) by dr Saito (http://www.fao.org/3/i9039en/I9039EN.pdf, https://www.riceadvice.info/en/riceadvice/). Importantly the RiceAdviceApp team has resolved issues raised by the authors in lines 364-366 of the paper. The app also runs offline (which is important given connectivity and price of internet in parts of Africa) – it synchronises once it is connected again. The developer of the app has actively promoted the app. Organised extensive trainings for service providers, thus overcoming issues of illiteracy. There is also a smart business model behind the app that allows for collaboration with private sector.

2.    Bioversity: I don’t know this institute so well. A search in scopus gives 50 hits (AFFILORG ( bioversity )  AND  TITLE-ABS-KEY ( crop  AND model ). Please have a look there yourself and complete your review

3.   ICARDA: A search in scopus gives 119 hits (AFFILORG ( ICARDA)  AND  TITLE-ABS-KEY ( crop  AND model ). Jacques Wery, the new DDG at ICARDA was recent keynote speaker at the ESA congress (Geneva, 2018) where he gave an inspiring one hour speech about crop modelling and integrated farm modelling. I guess he will be happy to give the authors an overview of what is happening at his institute. And not happy if you completely overlook what is happening at his institute.

4.    ICRAF/CIFOR: substantial modelling of tree crop species, scaling out to landscape and interactions with society and management. See works by M. van Noordwijk at CIFOR / ICRAF since the 1990s. For example substantial work has been done in Asia where large palmoil plantation development raises major environmental and societal issues. The paper only mentions a few works on agroforestry and intercropping in Africa. Much more has been done in this domain of crop modelling than what is mentioned in this paper.

5.    ILRI: substantial work on modelling crop-livestock-farm interactions. See for example works by van M.T. van Wijk, M. Herrero, M. Rufino. The manuscript barely mentions the fields of forage crop modelling and modelling crop-livestock-farm interactions.

6.    IWMI: I don’t know this institute so well. A search in scopus gives 66 hits (AFFILORG ( IWMI)  AND  TITLE-ABS-KEY ( crop  AND model ). Important environmental issues in our world today are groundwater depletion and salinization. Crop growth models can be used to design irrigation strategies and cropping pattterns that ensure sustainable groundwater uses and preventing salinization. Often this occurs at larger scales, requiring integration of remote sensing. Please have a look there yourself and complete your review.

7.    WorldFish: 3 hits in scopus. Safe to skip this institute in a paper about crop modelling.

8.    Intercropping. At the recent congress of the European Society of Agronomy (Geneva 2018) there was a lot of talk about intercropping. Institutes like IITA have long time and are still doing a lot of work in this domain, but almost exclusively through experimentation, almost no modelling. ICRAF is working on intercropping of tree crops, and mixtures of tree crops with annual crops . Only a bit of intercrop modelling by ICRAF is mentioned in the paper. Existing intercrop models are all still quite simple. Model improvement is necessary. Much of the intercropping model literature is on model design. In very limited cases have such models been used to design and optimise intercropping systems, in other words to use them for decision support. Recently scientific interest in intercropping is picking up. Has the crop modelling community neglected intercropping? Perhaps time for a revival?

Author Response

Recommendation: major revisions

This paper presents an overview of crop modelling by international crop research at the CGIAR centres. It is an impressive overview. Interesting sections are presented on main development in a number of approaches in the field of crop modelling and related fields. Illustrative case studies are presented. The authors have reviewed and cited an impressive number of 349 publications and provide a large coverage of the field.

Reply: We want to thank the reviewer for this comment

Major comments

Authors cite crop models, their history, development and applications for 8 out of 15 CGIAR centres (CIAT, CIMMYT, CIP, ICRAF, ICRISAT, IFPRI, IITA, IRRI). 8 out of 15 is not an overview, it is missing out on almost 50% of the CGIAR centres. An incomplete overview like this gives the false impression that no crop modelling is happening at the other 7 centres. Since these centres work in different domains, the paper automatically also misses out on important developments in crop modelling domains of CGIAR centres not covered in the paper in its current form.  

Below I list important institutes and crop modelling domains that I feel would need to be added to make the paper more complete. In alphabetical order:

Reply: We want to thank the reviewer for these comments and have addressed this issue as suggested. However, the manuscript does not pretend to cite all CGIAR papers on modeling, but more to offer an overview of the modeling activities within the CGIAR. We are currently developing a series of reviews that will describe extensively the crop modeling activities among CGIAR centers and collaborators.

1.    AfricaRice: The limited overview in the paper gives the false impression that it is only IRRI working on rice modelling. Substantial contributions to rice modelling have been made at AfricaRice. Here is a short overview

1.1.  1990’s: model improvements on a branch of ORYZA1 called ORYZASAHEL by Dingkuhn et al. A search in Scopus (AFFILORG ( warda )  AND  AUTHOR-NAME ( dingkuhn )) will give you 6 heavily cited papers from this period.

Reply: In table 1, new sections for AfricaRice’s publication (WARDA) have been added with some relevant citations. Unfortunately we have not been able to find all the suggested references and would be very grateful if the reviewer can facilitate these missing references to us (Wopereis Oryzasahel).

1.2.  2010’s: Model improvements on a branch of ORYZA2000 (AfricaRice version) by van Oort et al. (2015) and van Oort and Zwart ( 2018). Applications in yield gap analysis (van Oort et al 2015, 2017), cropping calendar optimisation (van Oort et al 2016) , GxE modelling in rice hybrids (El-Namaky and van Oort 2017) and climate change impact (van Oort and Zwart 2018).

Reply: we want to thank the reviewer for his contribution. We have added all the mentioned references in Table 1 accordingly and some other ones we found relevant.

1.3.  2010’s: Development of smart phone app for fertiliser recommendations  (RiceAdvice) by dr Saito (http://www.fao.org/3/i9039en/I9039EN.pdf, https://www.riceadvice.info/en/riceadvice/). Importantly the RiceAdviceApp team has resolved issues raised by the authors in lines 364-366 of the paper. The app also runs offline (which is important given connectivity and price of internet in parts of Africa) – it synchronises once it is connected again. The developer of the app has actively promoted the app. Organised extensive trainings for service providers, thus overcoming issues of illiteracy. There is also a smart business model behind the app that allows for collaboration with private sector.

Reply: Many thanks for the suggestions. We have added the corresponding information in section 4.2

2.    Bioversity: I don’t know this institute so well. A search in scopus gives 50 hits (AFFILORG ( bioversity )  AND  TITLE-ABS-KEY ( crop  AND model ). Please have a look there yourself and complete your review

Reply: Biodiversity does not have relevant publications in crop modelling

3.   ICARDA: A search in scopus gives 119 hits (AFFILORG ( ICARDA)  AND  TITLE-ABS-KEY ( crop  AND model ). Jacques Wery, the new DDG at ICARDA was recent keynote speaker at the ESA congress (Geneva, 2018) where he gave an inspiring one hour speech about crop modelling and integrated farm modelling. I guess he will be happy to give the authors an overview of what is happening at his institute. And not happy if you completely overlook what is happening at his institute.

Reply: Some examples of crop modeling at ICARDA were already mentioned in table 1. More relevant examples have been added to table 1.

4.    ICRAF/CIFOR: substantial modelling of tree crop species, scaling out to landscape and interactions with society and management. See works by M. van Noordwijk at CIFOR / ICRAF since the 1990s. For example substantial work has been done in Asia where large palmoil plantation development raises major environmental and societal issues. The paper only mentions a few works on agroforestry and intercropping in Africa. Much more has been done in this domain of crop modelling than what is mentioned in this paper.

Reply: CIFOR works in modeling forestry and not crops, this is the reason why the publications from this CG center have not been included. In Table 1, some Agroforestry and intercropping modelling examples were already included. We have added a couple of more examples in Table 1 and along the manuscript  (see section 6.1)

5.    ILRI: substantial work on modelling crop-livestock-farm interactions. See for example works by van M.T. van Wijk, M. Herrero, M. Rufino. The manuscript barely mentions the fields of forage crop modelling and modelling crop-livestock-farm interactions.

Reply:  Some examples of crop-livestock interactions have been added in sections 5.4 and 6.1. In table 1, some relevant examples have been newly cited.

6.    IWMI: I don’t know this institute so well. A search in scopus gives 66 hits (AFFILORG ( IWMI)  AND  TITLE-ABS-KEY ( crop  AND model ). Important environmental issues in our world today are groundwater depletion and salinization. Crop growth models can be used to design irrigation strategies and cropping pattterns that ensure sustainable groundwater uses and preventing salinization. Often this occurs at larger scales, requiring integration of remote sensing. Please have a look there yourself and complete your review.

Reply: The models described at IWMI are not relevant for cropping systems. In the manuscript we have already included examples about groundwater depletion and remote sensing (see sections 4.1 and 4.4)

7.    WorldFish: 3 hits in scopus. Safe to skip this institute in a paper about crop modelling.

Reply: We agree it is safe to skip this CG institute, as no crop modeling activities take place within this organization.

8.    Intercropping. At the recent congress of the European Society of Agronomy (Geneva 2018) there was a lot of talk about intercropping. Institutes like IITA have long time and are still doing a lot of work in this domain, but almost exclusively through experimentation, almost no modelling. ICRAF is working on intercropping of tree crops, and mixtures of tree crops with annual crops . Only a bit of intercrop modelling by ICRAF is mentioned in the paper. Existing intercrop models are all still quite simple. Model improvement is necessary. Much of the intercropping model literature is on model design. In very limited cases have such models been used to design and optimise intercropping systems, in other words to use them for decision support. Recently scientific interest in intercropping is picking up. Has the crop modelling community neglected intercropping? Perhaps time for a revival?

Reply: We have added some examples in table 1 and a paragraph in section 5.4 addressing this issue.

Round  2

Reviewer 2 Report

The paper has been well improved.