Simulate soil organic carbon with the ICBM two-pool model.

Analytical ICBM trajectory: a young and an old pool with a closed-form solution evaluated at integer years. A degenerate branch handles the case where the two effective rate constants coincide.

Usage

calculate_soc_icbm(
  initial_soc_mgc_ha,
  c_input_mgc_ha_yr,
  years,
  clay_pct = NA,
  climate_modifier = 1
)

Source

Andren, O. & Katterer, T. (1997). doi:10.1890/1051-0761(1997)007[1226:ITICBM]2.0.CO;2 .

Arguments

initial_soc_mgc_ha

Initial soil organic carbon stock (Mg C per ha).

c_input_mgc_ha_yr

Annual carbon input (Mg C per ha per year).

years

Number of years to simulate.

clay_pct

Soil clay content (percent); unused, kept for contract.

climate_modifier

Annual climate rate modifier (dimensionless), scaling both pool decomposition rates.

Value

A tibble with one row per year: year, y, o and soc_total.

Examples

calculate_soc_icbm(
  initial_soc_mgc_ha = 50,
  c_input_mgc_ha_yr = 2,
  years = 5
)
#> # A tibble: 6 × 4
#>    year     y     o soc_total
#>   <int> <dbl> <dbl>     <dbl>
#> 1     0  2.75  47.3      50  
#> 2     1  2.61  47.2      49.9
#> 3     2  2.55  47.2      49.8
#> 4     3  2.52  47.2      49.7
#> 5     4  2.51  47.2      49.7
#> 6     5  2.50  47.2      49.7