Calibration of grass-clover mixture

[Magnus Kamau Katana Lindhardt]

Dear community,

I have successfully calibrated winter wheat, spring barley and soybean (based on pea) with my site-specific measurements. I would also like to set up a calibration for my grass-clover crop and would be very grateful for some advice and guidance.

In Daisy, grass-clover is represented as two separate crops (e.g. ryegrass and white clover), but my field observations from my experiment (biomass yields per defoliation/cut) are only for the total harvest of the 'intercrop' (grass + clover). I also can't seem to find any literature that addresses this challenge.

I am concerned about "equifinality" (a given end state can be reached in many possible ways), if I try to adjust both species simultaneously towards a common objective goal (optimisation/calibration). And I don't even know if it is possible.

How do you usually work with an intercrop like grass-clover? 

Thank you in advance,

Cheers,

Kamau

[Per Abrahamsen]

Daisy usually has many ways to match measurements for a specific field experiment, so you need to limit the number of free parameters.  Otherwise, you will get "overfitting", a set of parameters that fit the optimization data very nicely but has very little predictive power when used on an independent dataset.

I haven't worked on grass-clover myself, but intuitively I would "trust" the grass parameterization more, as it is more widely used, and initially limit the optimization to clover parameters. 

Kindly,

Per A.

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[Magnus Kamau Katana Lindhardt]

Thanks Per!