Crop density

[jinmuluo]

Hi,

I have been looking around in the model and tech note, but there is not much information about the crop density/seeding density. I'm wondering how CLM accounts for crop density/seeding density in the model and how can I change this!

Thank you!

Jinmu Luo

 

[slevis]

Hi Jinmu,

I searched the Tech Note for a few minutes and found the answer here:

2.26. Crops and Irrigation — ctsm release-clm5.0 documentation

Then you need to find where this is done in the code and make the modifications that you have in mind.

 

[jinmuluo]

Hi Jinmu,

I searched the Tech Note for a few minutes and found the answer here:

2.26. Crops and Irrigation — ctsm release-clm5.0 documentation

Then you need to find where this is done in the code and make the modifications that you have in mind.

For anyone who also interested in this,
the parameter controls the seeding density is ' initial_seed_at_planting ' at the biogeochem/CNPhenologyMod.F90

 

[jinmuluo]

For anyone who also interested in this,
the parameter controls the seeding density is ' initial_seed_at_planting ' at the biogeochem/CNPhenologyMod.F90

Hi @slevis ,

I have changed this parameter by double or half it, even reducing it by 99% but the final crop uptake and crop product didn't change at all.
And under the code itself, here is a line written like

namelist /cnphenology/ initial_seed_at_planting, onset_thresh_depends_on_veg, &


min_critical_dayl_method, generate_crop_gdds, &


use_mxmat

does it mean that initial_seed_at_planting is inputted somewhere?

Best,

Jinmuluo

 

[slevis]

I had a quick look at clm's params file and did not see evidence of this parameter. However, the line that you quoted above suggests that you can change the value of this parameter using user_nl_clm. And there may be a default value that gets used when the parameter is not explicitly set.

So first I suggest this:
If you have been changing the value directly in the code, then try changing the value using your case's user_nl_clm.

If answers still do not change, I suggest tracking down the parameter throughout the code and adding write(iulog,*) statements to confirm the parameter's value everywhere that it appears. You could also add write statements for other variables where the parameter gets used, in order to develop an understanding of why your changes seem ignored.

 

[jinmuluo]

I had a quick look at clm's params file and did not see evidence of this parameter. However, the line that you quoted above suggests that you can change the value of this parameter using user_nl_clm. And there may be a default value that gets used when the parameter is not explicitly set.

So first I suggest this:
If you have been changing the value directly in the code, then try changing the value using your case's user_nl_clm.

If answers still do not change, I suggest tracking down the parameter throughout the code and adding write(iulog,*) statements to confirm the parameter's value everywhere that it appears. You could also add write statements for other variables where the parameter gets used, in order to develop an understanding of why your changes seem ignored.

Thank you! I did find "initial_seed_at_planting" in the "lnd_in" document and saw some changes in the simulation results after changes were made on user_nl_clm.