Fallow

[bodirsky]

🐦 Fallow land implementation 🐦

PR not yet ready for review

Include fallow into croparea and cropland implementations, similar to how it was used for the FST paper (Bodirsky et al 2025). When splitting up into cropland and croparea realization, the fallow implementation was not implemented in a functional way, so this is largely a bugfix.

• Briefly explain the purpose of this pull request

🔧 Checklist for PR creator 🔧

If a point is not applicable, check the checkbox anyway and write "non-applicable" next to the checkbox.

• Label pull request from the label list.

  • Low risk: Simple bugfixes (missing files, updated documentation, typos) or changes in start or output scripts
  • Medium risk: Uncritical changes in the model core (e.g. moderate modifications in non-default realizations)
  • High risk: Critical changes in model core or default settings (e.g. changing a model default or adjusting a core mechanic in the model)

• Self-review own code

  • No hard coded numbers and cluster/country/region names.
  • The new code doesn't contain declared but unused parameters or variables.
  • magpie4 R library has been updated accordingly and backwards compatible where necessary.
  • scenario_config.csv has been updated accordingly (important if default.cfg has been updated)

• Document changes

  • Add changes to CHANGELOG.md
  • Where relevant, put In-code documentation comments
  • Properly address updates in interfaces in the module documentations
  • run goxygen::goxygen() and verify the modified code is properly documented

• Perform test runs

  • Low risk:
    • Run a compilation check via Rscript start.R --> "compilation check"
  • Medium risk:
    • Run default run via Rscript start.R --> "default"
    • Check logs for errors/warnings
    • Fill in performance section below
  • High risk:
    • Run test runs via Rscript start.R --> "test runs"
    • Check logs for errors/warnings
    • Default run from the PR target branch for comparison
    • Provide relevant comparison plots (land-use, emissions, food prices, land-use intensity,...)
    • Fill in performance section below

• Reporting produces no errors and no new warnings

• Get two approving reviews (at least one from RSE)

📉 Performance 📈

• This PR's default : ** mins
• For comparison: runtimes of weekly test

🚨 Checklist for reviewer 🚨

• PR is labeled correctly
• Code changes look reasonable
  • No hard coded numbers and cluster/country/region names.
  • No unnecessary increase in module interfaces
  • model behavior/performance is satisfactory.
• Changes are properly documented
  • CHANGELOG is updated correctly
  • Updates in interfaces have been properly addressed in the module documentations
  • In-code documentation looks appropriate

[FelicitasBeier]

@bodirsky I'll comment here so that we keep that in mind for the GAMS code implementation that comes with the Croparea Update: We use "harvested area", not "physical area" in calcEFch4Rice. This requires a small update in the GAMS code.