I need help

[TC-02-tceh]

I encountered some problems when setting up intercropping between cotton and mung beans. Specifically, the model did not report any errors, but the dry matter of cotton showed a cliff like growth, and the cotton harvest yield was zero, but the mung bean yield still existed. How should I modify it.

[peter-devoil]

Have a look in the summary file to see if there are any diagnostic messages - perhaps the crop died or matured?

[TC-02-tceh]

Thank you very much for your reply. I have checked the summary file and found that there is an error issue with the model. Specifically
APSIM Warning Error

Uninitialised variable "wht_sow_opp_num".
Variables should have a value before they are used in an expression.
Component name: paddock.Sow using a variable rule with intercropping
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
At the same time, it was found that only cotton was sown in the summary file, without any information about cotton simulation. I would like to ask you how to modify this problem.

[peter-devoil]

The warning can be ignored (it's been there forever)..

The last image shows the cotton crop is being ended by some logic that ends the crop on a fixed date. Perhaps it hasnt set any flowers?

Most crops use summed temperature to estimate reproductive development. Are you running this crop in a cool environment? Perhaps you could see if any other cultivars in the cotton module mature earlier?

[TC-02-tceh]

Thank you very much for your reply. The crop planting environment is a temperate continental climate with sufficient sunlight. Following your suggestion, I found that the dry weight of cotton in the output file did not change after changing the cotton variety. May I ask how to modify the model.

[peter-devoil]

a) 500 plants / m^2 seems like a lot for cotton (in this part of the world, it's usually <15)

b) if it's not growing, there must be some limit stopping it (provided radiation & temperature are ok). Have a look for water and N stresses. I see 20 kg fertiliser applied - 200kg may be more appropriate.

c) you can change the model if you understand the codes revealed by the "advanced" button. The descriptions are (mostly) in the Hearn paper.

[TC-02-tceh]

Thank you very much for your reply. I hope you have a pleasant life. Additionally, I would like to ask you a question: are there any videos on YouTube about crop intercropping using the Apsim model.

[peter-devoil]

Not that I'm aware of - the primary resource is Carberry's implementation paper from the '90s. I would use caution with mungbean + cotton, as (in aust) cotton is rarely anything other than monocrop. It may not respect the conventions of sharing intercepted radiation from the canopy module - and as the source is "commercial" and hidden from us, there's no easy way to find out.

You may have better luck with the prototype cotton module in nextgen, which will do resource allocation properly.