> For the complete documentation index, see [llms.txt](https://swatplus.gitbook.io/io-docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://swatplus.gitbook.io/io-docs/introduction-1/carbon.md). # Carbon The following input files are the minimum requirements to set up the carbon model using SWAT+
Input FilesDescription
Basin (codes.bsn, parameters.bsn)Files include control codes for basin-level processes simulation and basin-level parameters, respectively
Carbon Coefficients (carb_coefs.cbn)Coefficients needed to simulate the carbon fluxes (optional; if not present, default values will be used)
Climate (weather-sta.cli, weather-wgn.cli, pcp.cli, tmp.cli, slr.cli, hmd.cli, wnd.cli, atmo.cli)Files list the weather stations and weather data for model input

Databases (plants.plt, urban.urb, tillage.til, fertilizer.frt, pesticide.pes, septic.sep)

SWAT+ database for plants, landuse, tillage, fertilizer and manure, pesticides, and septic systems, respectively
HRU (hru-data.hru, topography.hyd, hydrology.hyd, field.fld, snow.sno)Files contain the site-specific topographical and hydrological properties of HRUs

Landuse and Management (landuse.lum,

​plant.ini, management.sch,cntable.lum, cons_prac.lum, ovn_table.lum)

Files contain landuse information, management operations, and schedules necessary for crop growth
Master File (file.cio)Files list the names of all input files used in a simulation run
Soils (soils.sol, soil_lyr_depths.sol, nutrients.sol)Files contain physical soil properties, customized soil layer depth, contents of nutrients and constituents as initialized in the file soil_plant.ini.
Structural Practices (tiledrain.str, filterstrip.str, grassedww.str, bmpuser.str, septic.str)Files contain parameters related to structural practices

Simulation (time.sim, print.prt, object.prt)

Files control simulation time, and output files will be printed during the simulation

**To view carbon-specific outputs, the following objects should be added to the print.prt file :

[^1]: **what is this printing actually?**