Simple dynamic model of soil carbon content, with a time step of one year. The equations that describe the dynamics of this system are adapted from the Henin-Dupuis model described in Jones et al. (2004). The soil carbon content is represented by a single state variable: the mass of carbon per unit land area in the top 20 cm of soil in a given year (Z, kg.ha-1). It is assumed that soil C is known in some year, taken as the initial year. The yearly change in soil C is the difference between input from crop biomass and loss.
carbonsoil.model(R, b, U, Z1, duration): the fraction of soil carbon content lost per year
: the fraction of yearly crop biomass production left in the soil
: the amount of C in crop biomass production (constant or time series)
: initial soil carbon content
: duration of simulation (year))
Soil carbon years.