diff --git a/README.md b/README.md index b06db2a..35d14b6 100644 --- a/README.md +++ b/README.md @@ -22,13 +22,57 @@ tools for analysing model outputs and performance. ## Contents -1. [Installation](#installation) -2. [Getting Started](#getting-started) +1. [What is this for?](#what-is-this-for?) +2. [Installation](#installation) +3. [Getting Started](#getting-started) 4. [Contributing](#contributing) 5. [Contact](#contact) -3. [Glossary](#glossary) +6. [Glossary](#glossary) 7. [Footnotes and References](#footnotes-and-references) +## What is this for? + +This `R` package allows simulation of grass growth. + +### Why simulate grass growth? + +Grasslands constitute one of Earth's most widespread terrestrial +ecosystems[^3] and a core element in global agriculture, providing roughly +half the feed inputs for global livestock systems +[^4]. +Beside their contribution to global food production, they provide a catalogue +of other ecosystem services, such as water flow and erosion regulation, +pollination service, carbon sequestration and climate regulation +[^3]. +The latter have become particularly important in light of anthropogenic +climate change [^5]. + +Understanding the functioning of grassland ecosystems and their responses to +external changes is therefore of significant interest. +Vegetation models provide a powerful platform for such studies. + +### How does this compare to other grass and vegetation models? + +The number of grassland models is large and ever-growing. +We can therefore not give a comprehensive list, but will try to make a couple +of representative comparisons to illustrate where `growR` has its niche. +For the most part, an advantage of `growR` over other, similar models and +their implementations is its distribution as `R` package via CRAN. + +- The [Hurley Pasture Model](https://sites.massey.ac.nz/hurleypasturemodel/hurley-pasture-model/) [^6] + is a detailed mechanistic model for managed pastures. It is implemented in + the *Advanced continuous simulation language (ACSL)* and the source code is + available on request. +- [BASGRA](https://github.com/davcam/BASGRA/) [^7] + and its descendant [BASGRA_N](https://github.com/MarcelVanOijen/BASGRA_N) + [^8] are multi-year grassland models which include tiller dynamics. + They are also implemented in `R` with the source code freely available. + However, they do not come packaged, as `growR` does. +- PROGRASS [^9] was developed to capture the interactions in grass/clover + mixtures. As of this writing, no accessible implementation was found. +- The focus of PaSim [^10] is the investigation of livestock production, + which is not directly covered in `growR`, under climate change conditions. + ## Installation ### From CRAN @@ -191,6 +235,45 @@ Simulate the Seasonal Effects of Drought on Herbage Growth“. Field Crops Research 187 (Februar 2016): 12–23. [doi:10.1016/j.fcr.2015.12.008](https://doi.org/10.1016/j.fcr.2015.12.008). +[^3]: Zhao, Yuanyuan, Zhifeng Liu, and Jianguo Wu. “Grassland Ecosystem +Services: A Systematic Review of Research Advances and Future Directions.” +Landscape Ecology 35, no. 4 (April 1, 2020): 793–814. +[doi:10.1007/s10980-020-00980-3](https://doi.org/10.1007/s10980-020-00980-3). + +[^4]: Herrero, Mario, Petr Havlík, Hugo Valin, An Notenbaert, Mariana C. +Rufino, Philip K. Thornton, Michael Blümmel, Franz Weiss, Delia Grace, and +Michael Obersteiner. “Biomass Use, Production, Feed Efficiencies, and +Greenhouse Gas Emissions from Global Livestock Systems.” Proceedings of the +National Academy of Sciences 110, no. 52 (December 24, 2013): 20888–93. +[doi:10.1073/pnas.1308149110](https://doi.org/10.1073/pnas.1308149110). + +[^5]: IPCC Report 2022, Chapter 5. + +[^6]: Thornley, J. H. M. Grassland Dynamics: An Ecosystem Simulation Model. +CAB International, 1998. + +[^7]: Van Oijen, M., M. Höglind, D.R. Cameron, and S.M. Thorsen. +“BASGRA_2014.” Zenodo, August 13, 2015. https://doi.org/10.5281/zenodo.27867. + +[^8]: Höglind, Mats, David Cameron, Tomas Persson, Xiao Huang, and Marcel van +Oijen. “BASGRA_N: A Model for Grassland Productivity, Quality and Greenhouse +Gas Balance.” Ecological Modelling 417 (February 1, 2020): 108925. +[doi:10.1016/j.ecolmodel.2019.108925](https://doi.org/10.1016/j.ecolmodel.2019.108925). + +[^9]: Lazzarotto, P., P. Calanca, and J. Fuhrer. “Dynamics of Grass–Clover +Mixtures—An Analysis of the Response to Management with the PROductive +GRASsland Simulator (PROGRASS).” Ecological Modelling 220, no. 5 (March 10, +2009): 703–24. +[doi:10.1016/j.ecolmodel.2008.11.023](https://doi.org/10.1016/j.ecolmodel.2008.11.023). + +[^10]: Graux, A. -I., M. Gaurut, J. Agabriel, R. Baumont, R. Delagarde, L. +Delaby, and J. -F. Soussana. “Development of the Pasture Simulation Model for +Assessing Livestock Production under Climate Change.” Agriculture, Ecosystems +& Environment 144, no. 1 (November 1, 2011): 69–91. +[doi:10.1016/j.agee.2011.07.001](https://doi.org/10.1016/j.agee.2011.07.001). + + + [^3]: If you make changes that generally improve `growR`, it would be great if you could share them to make them available to all future users. See [Contributing](#contributing).