Green sentences refer to the input needed by modellers to implement the model.
The production function could simply be a matrix for instance. Obviously we need models of the farm. Such models probably exist and the help of specialists in agriculture whould be appreciated in providing them to modellers. Even if we don't have complete models including farmers utility functions, the production functions would already be very helpful. Furthermore, in terms of needed data, farm models include local constraints such as labour, inputs and products markets than should be collected.