Decomposition and Mineralisation - Soil organisms explicit
Microbes can also be treated explicitly i.e. a pool for microbial biomass is included in the simulations. This can be useful for example when simulating forest ecosystems because in forest soils the humified products have an essentially higher CN ratio than the microbes. It is the CN ratio in the microbial biomass that determines the net mobilisation/immobilisation rate and therefore microbial biomass is better expressed explicitly for these soils.
The different organic carbon pools and the carbon flows between them, when soil organisms are explicitly simulated, are illustrated in Figure 5.2. The external inputs have already been described thoroughly in the section External inputs and will therefore not be discussed further.
Figure 5.2. The organic carbon pools and carbon flows in the soil. The coloured sections in the microbial pool correspond to the fractions of microbials located in the litter, faeces and humus pools respectively (i.e. the sub pools in the microbial pool).
Fluxes of carbon to the microbial pool from the humus,
litter and faeces pools
Organic nitrogen fluxes related to the soil organic carbon
fluxes