carb_coefs.cbn
The carb_coefs.cbn file enables adjustment of sensitive carbon balance parameters. Also contains configuration settings supporting carbon balance simulation. Applies when codes.bsn carbon = 1
carbon diagnostics setting controlling hru_cb output
cbn_diagnostics
Output file setting 0 - two SOC output files: hru_cbn_lyr, hru_seq_lyr 1 - seven output files: above + hru_cflux_stat, hru_cpool_stat, hru_n_p_pool_stat, hru_begin_soil_prop, and hru_end_soil_prob
carbdb data structure coefficients controlling carbon transformation and flux
hp_rate
passive pool daily maximum potential transformation (decomposition) rate; separate values for 10mm soil layer and soil layers below 10mm.
hs_rate
slow pool daily maximum potential transformation rate; separate values for 10mm soil layer and soil layers below 10mm.
microb_rate
microbial pool daily maximum potential transformation rate; separate values for 10mm soil layer and soil layers below 10mm.
meta_rate
metabolic litter pool daily maximum potential transformation rate; separate values for 10mm soil layer and soil layers below 10mm.
str_rate
structural litter pool daily maximum potential transformation ratem; separate values for 10mm soil layer and soil layers below 10mm.
microb_top_rate
adjusts microbial activity in top 10mm layer; separate values for 10mm soil layer and soil layers below 10mm.
hs_hp
fraction of daily transformed slow pool allocated to passive pool; separate values for 10mm soil layer and soil layers below 10mm.
org_allo data structure coefficients controlling carbon dioxide emission
a1co2
fraction of daily transformed metabolic and non-lignin structural litter carbon emitted as CO2; separate values for 10mm soil layer and soil layers below 10mm.
asco2
fraction of daily transformed slow pool carbon emitted as CO2; separate values for 10mm soil layer and soil layers below 10mm.
apco2
fraction of daily transformed passive pool carbon emitted as CO2; separate values for 10mm soil layer and soil layers below 10mm.
abco2
fraction of daily transformed microbial pool carbon emitted as CO2; separate values for 10mm soil layer and soil layers below 10mm.
fraction of initial carbon from soils.sol allocated to microbial, slow, and passive pools
org_frac
frac_litter
fraction of soils.sol carbon added as litter pool carbon (soils.sol carbon value is sequestered carbon, default litter fraction 0.05)
frac_hum_microb
fraction of soils.sol carbon allocated to microbial pool (default 0.02)
frac_hum_slow
fraction of soils.sol carbon allocated to slow pool (default 0.44)
fract_hum_passive
fraction of soils.sol carbon allocated to passive pool (default 0.54, recommended adjustment per Mathers et al 2026)
dissolved carbon partitioning coefficients
prmt_21
organic carbon-water partition coefficient reflecting strength binding to organic matter versus dissolved in water
prmt_44
ratio of surface runoff C concentration to percolate C concentration
number of days tillage events will be effective
till_eff_days
number of days a tillage event affects carbon pool decomposition
manure carbon, nitrogen, and phosphorus partitioning coefficient
rtof
fraction used to partition C, N, and P to fresh manure and stable (slow humus, particulate organic matter) pool
factors affecting soil consolidation (settling) with biomixing and following tillage
cbn_consolidation_factors
bio_consf
biomixing consolidation factor controlling level at which soil remains churned with biomixing (default 0.15)
till_consf
tillage consolidation factor controlling rate at which soil settles after tillage (default 0.10)
soil temperature and moisture factor methods (from Liang et al 2022)
tmpf
soil temperature factor method: 1 - Izaurralde et al 2006; 2 - Kemanian et al 2011; 3 - Sharpley & Williams 1990
watf
soil water factor method: 1 - Neitsch et al 2011; 2 - Kemanian et al 2011
soil temperature factor method 2 equation parameters
tn
minimum soil temperature (deg C)
top
optimum soil temperature (deg C)
tx
maximum soil temperature (deg C)
bio and tillage mixing coefficients for tillage factor method 3 (mgt_tillfactor.f90)
zz_bmix_coefs
zz_bmix_coef_a
controls biomixing factor base level
zz_bmix_coef_b
controls upper biomixing factor magnitude
zz_bmix_coef_c
controls clay content effect reducing biomixing factor
zz_bmix_coefs
zz_bmix_coef_a
controls tillage factor base level
zz_bmix_coef_b
controls upper tillage factor magnitude
zz_bmix_coef_c
controls clay content effect reducing tillage factor
surface residue photo degradation factor
photo_degrad_factor
parameter controlling daily rate at which residue photo-degrades (default set very low at 0.0001)
soil test results updating soils.sol parameters
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