ELM_crop

# Note here we do a CLMSP simulation as that is what has been validated
> cd scripts
> ./create_newcase -case IRRIG -res f19_g17_gl4 -compset I1850Clm50BgcCrop
> cd IRRIG

# Append "-irrig on" to CLM_BLDNML_OPTS in env_run.xml (you could also use an editor)
> ./xmlchange CLM_BLDNML_OPTS="-irrig on" -append

> ./case.setup

# Now build and run normally
> ./case.build
> ./case.submit

https://escomp.github.io/ctsm-docs/versions/release-clm5.0/html/users_guide/running-special-cases/running-with-irrigation.html

In CLM4.0 irrigation isn’t an allowed option. In CLM4.5 irrigation can ONLY be used WITH crop. With CLM5.0 irrigation can be used whether crop is on or not – BUT if crop is off, your surface datasets HAVE to have irrigation defined appropriately. Right now ALL surface datasets without crop enabled have irrigation hard-wired on. In order to create datasets with irrigation off, you’d need to make changes to mksurfdata_map in order to have all generic crops to be non-irrigated. To turn on irrigation in CLM5.0 we simply add “-irrig on” to CLM_BLDNML_OPTS.