DCaPS (Diurnal Canopy Photosynthesis Simulator)

About DCaPS

DCaPS is a model that can simulate diurnal canopy photosynthesis of both C3 and C4 field crops. It is driven by diurnal environmental variables and canopy attributes, and represents the canopy with the sun-shade modelling approach, to calculate diurnal canopy photosynthesis and daily above-ground biomass accumulation. The model can be used to assess consequences of photosynthetic changes and/or incorporated into crop growth and development model.

For a working web-based application of DCaPS, please visit http://www.dcaps.net.au. For model detail, please visit the documentation page on http://www.dcaps.net.au.

Code Structure

There are several classes which are all owned by the PhotosynthesisModel class. Following is a list of the main sub model and a brief list of their functionality:

• EnvironmentModel
  • Calculates solar geometry
  • Calculates diurnal radiation, temperature and VPD
• LeafCanopy
  • Calculates diurnal sunlit / shaded LAI (Leaf Area Index)
  • Calculates absorbed radiation
  • Calculates leaf nitrogen
• SunlitCanopy / ShadedCanopy
  • Calculates absorbed radiation
  • Calculates assimilation through rubisco and electron transport

Using the model

The source code is a C# .Net project and can be used with several development UI's eg. Microsoft Visual Studio.

The code does not use any non standard libraries.

Included in the project is a console application that instantiates a PhotoSynthesis model and runs it for both the C3 and C4 pathways. All of the parameters and variables are properties of the particular class and can be set directly.

All parameters have default values.

• Step 1 - Instantiate a PhotosynthesisModel

PhotosynthesisModel PM = new PhotosynthesisModel();

• Step 2 - Set the desired photosynthetic pathway

PM.photoPathway = PhotosynthesisModel.PhotoPathway.C3;

• Step 3 - Set the location (latitude) and daily environmental parameters

//Set the latitude
PM.envModel.latitude = new Angle(-27.5, AngleType.Deg);

//Set Ambient air CO2 partial pressure
PM.canopy.Ca = 400;

//Set the daily environmental variables
PM.envModel.DOY = 298;
PM.envModel.maxT = 21;
PM.envModel.minT = 7;

• Step 4 - Set the leaf architecture and nitrogen status

//Set the leaf angle
PM.canopy.leafAngle = 60;

//Set daily LAI and SLN values
PM.canopy.LAI = 6;
PM.canopy.CPath.SLNAv = 1.45;

• Step 5 - Run the model

PM.envModel.initilised = true;
PM.initialised = true;

//Run the model
PM.runDaily();

Citation

If you use this model or the website http://www.dcaps.net.au in your research, please cite the main research paper that this software supports, using the following citation:

Wu, Alex., Doherty, Al., Farquhar, Graham D., and Hammer, Graeme L. (2017) Simulating daily field crop canopy photosynthesis: an integrated software package. Functional Plant Biology 45, 362-377. https://doi.org/10.1071/FP17225

Feedback

https://github.com/QAAFI/DCaPS