SoilR (version 1.0-0)

ICBMModel: Implementation of the Introductory Carbon Balance Model (ICBM)

Description

This function is an implementation of the Introductory Carbon Balance Model (ICBM). This is simply a two pool model connected in series.

Usage

ICBMModel(t, ks = c(k1 = 0.8, k2 = 0.00605), h = 0.13, r = 1.32, 
    c0 = c(Y0 = 0.3, O0 = 3.96), In = 0)

Arguments

t

A vector containing the points in time where the solution is sougth.

ks

A vector of length 2 with the decomposition rates for the young and the old pool.

h

Humufication coefficient (transfer rate from young to old pool).

r

External (environmental or edaphic) factor.

c0

A vector of length 2 with the initial value of carbon stocks in the young and old pool.

In

Mean annual carbon input to the soil.

References

Andren, O. and T. Katterer. 1997. ICBM: The Introductory Carbon Balance Model for Exploration of Soil Carbon Balances. Ecological Applications 7:1226-1236.

See Also

TwopSeriesModel

Examples

#This example reproduces the simulations presented in Table 1 of Andren and Katterer (1997).
#First, the model is run for different values of the parameters representing different field experiments. 
times=seq(0,20,by=0.1)
Bare=ICBMModel(t=times) #Bare fallow
pNpS=ICBMModel(t=times, h=0.125, r=1,    c0=c(0.3,4.11),  In=0.19+0.095) #+N +Straw
mNpS=ICBMModel(t=times, h=0.125, r=1.22, c0=c(0.3, 4.05), In=0.19+0.058) #-N +Straw
mNmS=ICBMModel(t=times, h=0.125, r=1.17, c0=c(0.3, 3.99), In=0.057) #-N -Straw
pNmS=ICBMModel(t=times, h=0.125, r=1.07, c0=c(0.3, 4.02), In=0.091) #+N -Straw
FM=ICBMModel(t=times, h=0.250, r=1.10, c0=c(0.3, 3.99), In=0.19+0.082) #Manure
SwS=ICBMModel(t=times, h=0.340, r=0.97, c0=c(0.3, 4.14), In=0.19+0.106) #Sewage Sludge
SS=ICBMModel(t=times, h=0.125, r=1.00, c0=c(0.25, 4.16), In=0.2)  #Steady State

#The amount of carbon for each simulation is recovered with the function getC
CtBare=getC(Bare)
CtpNpS=getC(pNpS)
CtmNpS=getC(mNpS)
CtmNmS=getC(mNmS)
CtpNmS=getC(pNmS)
CtFM=getC(FM)
CtSwS=getC(SwS)
CtSS=getC(SS)

#This plot reproduces Figure 1 in Andren and Katterer (1997)
plot(times, rowSums(CtBare),type="l",ylim=c(0,8),xlim=c(0,20),ylab="Topsoil carbon mass (kg m-2)",xlab="Time (years)")
lines(times,rowSums(CtpNpS),lty=2)
lines(times,rowSums(CtmNpS),lty=3)
lines(times,rowSums(CtmNmS),lty=4)
lines(times,rowSums(CtpNmS),lwd=2)
lines(times,rowSums(CtFM),lty=2,lwd=2)
lines(times,rowSums(CtSwS),lty=3,lwd=2)
#lines(times,rowSums(CtSS),lty=4,lwd=2)
legend("topleft",c("Bare fallow", "+N +Straw", "-N +Straw", "-N -Straw", "+N -Straw", "Manure","Sludge"),lty=c(1,2,3,4,1,2,3),lwd=c(1,1,1,1,2,2,2),bty="n")