Simulating carbon dioxide fertilisation in crops

To model crop growth under the higher atmospheric carbon dioxide concentrations that will occur in the future, there needs to be and accurate representation of the link between atmospheric carbon dioxide concentrations and growth.

A review of APSIM’s crop models showed that carbon dioxide fertilisation effects were well founded, tested and documented in a number of important (mainly C3 crops) crops, notably wheat. There was agreement that many of these well founded representations could be generalised to other crops with similar photosynthetic pathways (e.g. generalising the science in wheat to other C3 crops). The situation was less well substantiated in crops with the C4 photosynthetic pathway.

The overall conclusion is that for a range of important crops, the general situation of representing carbon dioxide fertilisation effects on photosynthesis and transpiration in APSIM was close to the ‘state of the art’ given current understanding of, and data on the processes involved, and the aims of the APSIM model. There is an immediate need for better documentation of the representation of carbon dioxide fertilisation in APSIM, and a strategic need for further research and model development in this area.

For further details see the new paper titled Responses to atmospheric CO₂ concentrations in crop simulation models: a review of current simple and semicomplex representations and options for model development published in Global Change Biology at the following link.

The current status of the representation, parameterisation and validation of CO₂ fertilisation of plants in APSIM compiled by Vanuytrecht and Thorburn is also available here