Function implementing a modification of the DAYCENT carbon decomposition model (Parton et al. 1988, 1993, 1998), inspired by the description given in Chapter 18 of Bonan (2019).
Usage
decomposition_DAYCENT(
snags,
litter,
SOC,
paramsLitterDecomposition,
paramsAnatomy,
baseAnnualRates,
annualTurnoverRate,
environmentalConditions,
litterProduction,
sand,
clay,
soilPH,
soilO2 = 1,
cultfac = 1,
tstep = 1,
balanceCheck = FALSE
)Arguments
- snags
A data frame with initial dead standing (snag) cohort information (see
growthInput).- litter
A data frame with initial aboveground and belowground structural carbon pools corresponding to plant cohorts, in g C/m2 (see
growthInput).- SOC
A named numeric vector with initial metabolic, active, slow and passive carbon pools for surface and soil, in g C/m2 (see
growthInput).- paramsLitterDecomposition
A data frame of species-specific litter decomposition parameters (see
growthInput).- paramsAnatomy
A data frame of species-specific anatomy parameters (see
growthInput).- baseAnnualRates
A named vector of annual decomposition rates, in yr-1 (see
defaultControl).- annualTurnoverRate
Annual turnover rate, in yr-1 (see
defaultControl).- environmentalConditions
A data frame containing environmental conditions for each time step to simulate:
AirTempperature: Mean air temperature (in Celsius).AirRelativeHumidity: Mean relative humidity (percent).SoilTemperature: Mean soil temperature (in Celsius).SoilMoisture: Mean soil moisture, relative to saturation (0-1).
- litterProduction
A data frame containing litter inputs corresponding to time steps:
Step: Integer indicating the time step where litter is generated, corresponding to a row inenvironmentalConditions.Species: Mean relative humidity (percent).Leaves: Leaf litter production (g C·m-2).Twigs: Twig litter production (g C·m-2).SmallBranches: Small branch litter production (g C·m-2).LargeWood: Large wood litter production (g C·m-2).CoarseRoots: Coarse root litter production (g C·m-2).FineRoots: Fine root litter production (g C·m-2).
- sand, clay
Soil texture (sand and sand) in percent volume (percent).
- soilPH
Soil pH (0-14).
- soilO2
Soil oxygen factor (0-1).
- cultfac
Cultivation factor (0-1).
- tstep
Time step in days. By default, one day. For annual time steps, use
tstep = 365.25.- balanceCheck
Flag to print carbon balance check (for debugging).
Value
A list with two elements:
"HeterotrophicRespiration": A numeric matrix with the heterotrophic respiration (g C·m-2) corresponding to the decomposition in each time step corresponding to different carbon pools:"SurfaceSnags": Respiration from decomposing snags (i.e. small branches and large wood)."SurfaceLitter": Respiration from decomposing litter in the surface (i.e. leaves, twigs, small branches and large wood)."SoilLitter": Respiration from decomposing litter belowground (i.e. coarse roots and fine roots)."SurfaceMetabolic": Respiration from surface metabolic pool."BelowgroundMetabolic": Respiration from belowground metabolic pool."SurfaceActive": Respiration from surface active pool."BelowgroundActive": Respiration from belowground active pool."SurfaceSlow": Respiration from surface slow pool."BelowgroundSlow": Respiration from belowground slow pool."BelowgroundPassive": Respiration from belowground passive pool.
"DecompositionPools": A numeric matrix with the carbon mass of different carbon pools, all in g C · m-2:"SmallBranchSnags": Carbon of (standing) small dead branches (diameters between 0.635 cm and 7.5 cm; 10h and 100h fuels)."LargeWoodSnags": Carbon of (standing) large dead wood (diameters larger than 7.5 cm; 1000h and 10000h fuels)."LeafLitter": Carbon of leaf litter."TwigLitter": Carbon of twig litter."SmallBranchLitter": Carbon of (downed) small dead branches (diameters between 0.635 cm and 7.5 cm; 10h and 100h fuels)."LargeWoodLitter": Carbon of (downed) large dead wood (diameters larger than 7.5 cm; 1000h and 10000h)."CoarseRootLitter": Carbon of dead coarse roots."FineRootLitter": Carbon of fine root litter."SurfaceMetabolic": Metabolic carbon in the surface."BelowgroundMetabolic": Metabolic carbon in the soil."SurfaceActive": Active decomposition carbon pool in the surface."BelowgroundActive": Belowground active decomposition carbon pool."SurfaceSlow": Slow decomposition carbon pool in the surface."BelowgroundSlow": Belowground slow decomposition carbon pool."BelowgroundPassive": Belowground passive decomposition carbon pool.
Details
Species names must match between inputs paramsLitterDecomposition, litter and litterProduction.
IMPORTANT NOTE: Decomposition functions modify the input data (i.e. snags, litter and/or SOC) according to decomposition rates and carbon transfer rates. When used as part of growth simulations,
soil physical and chemical parameters correspond to the uppermost soil layer.
References
Bonan, G. (2019). Climate change and terrestrial ecosystem modeling. Cambridge University Press, Cambridge, UK.
Parton WJ, Steward JWB, Cole CV (1988). Dynamics of C, N, P and S in grassland soils: a model. Biogeochemistry 5: 109-131.
Parton WJ, Scurlock JMO, Ojima DS, Gilmanov TG, Scoles RJ et al. (1993). Observations and modeling of biomass and soil organic matter dynamics for the grassland biome worldwide. Global Biogeochemical Cycles 7: 785-809.
Parton WJ, Hartman M, Ojima DS, Schimel D (1998). DAYCENT and its land surface submodel: Description and testing. Global and Planetary Change, 19: 35-48.
