42: Implementation of the Century model
In SoilR: Models of Soil Organic Matter Decomposition

Description Usage Arguments Value Author(s) References See Also Examples

This function implements the Century model as described in Parton et al. (1987).

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CenturyModel(t, ks = c(k.STR = 0.094, k.MET = 0.35, k.ACT = 0.14, 
    k.SLW = 0.0038, k.PAS = 0.00013), C0 = c(0, 0, 0, 0, 0), 
    In, LN, Ls, clay = 0.2, silt = 0.45, xi = 1, solver = deSolve.lsoda.wrapper)

`t`	A vector containing the points in time where the solution is sought.
`ks`	A vector of lenght 5 containing the values of the decomposition rates for the different pools. Units in per week.
`C0`	A vector of length 5 containing the initial amount of carbon for the 5 pools.
`In`	A scalar or data.frame object specifying the amount of litter inputs by time (mass per area per week).
`LN`	A scalar representing the lignin to nitrogen ratio of the plant residue inputs.
`Ls`	A scalar representing the fraction of structural material that is lignin.
`clay`	Proportion of clay in mineral soil.
`silt`	Proportion of silt in mineral soil.
`xi`	A scalar or data.frame object specifying the external (environmental and/or edaphic) effects on decomposition rates.
`solver`	A function that solves the system of ODEs. This can be `euler` or `ode` or any other user provided function with the same interface.

A Model Object that can be further queried

Carlos A. Sierra, Markus Mueller

Parton, W.J, D.S. Schimel, C.V. Cole, and D.S. Ojima. 1987. Analysis of factors controlling soil organic matter levels in Great Plain grasslands. Soil Science Society of America Journal 51: 1173–1179. Sierra, C.A., M. Mueller, S.E. Trumbore. 2012. Models of soil organic matter decomposition: the SoilR package version 1.0. Geoscientific Model Development 5, 1045-1060.

RothCModel

t=seq(0,52*200,1) #200 years  
LNcorn=0.17/0.004 # Values for corn clover reported in Parton et al. 1987
Ex=CenturyModel(t,LN=0.5,Ls=0.1,In=0.1)
Ct=getC(Ex)
Rt=getReleaseFlux(Ex)

matplot(t,Ct,type="l", col=1:5,lty=1,ylim=c(0,max(Ct)*2.5),
  ylab=expression(paste("Carbon stores (kg C", ha^-1,")")),xlab="Time (weeks)") 
lines(t,rowSums(Ct),lwd=2)
legend("topright", c("Structural litter","Metabolic litter",
    "Active SOM","Slow SOM","Passive SOM","Total Carbon"),
  lty=1,lwd=c(rep(1,5),2),col=c(1:5,1),bty="n")

matplot(t,Rt,type="l",lty=1,ylim=c(0,max(Rt)*3),ylab="Respiration (kg C ha-1 week-1)",xlab="Time") 
lines(t,rowSums(Rt),lwd=2) 
legend("topright", c("Structural litter","Metabolic litter",
                     "Active SOM","Slow SOM","Passive SOM","Total Respiration"),
       lty=1,lwd=c(rep(1,5),2),col=c(1:5,1),bty="n")