Standing dead biomass falls to the ground and becomes litter. The specific rate of fall of standing dead into the litter pool is modeled as a function of trampling and rainfall. Digestibility changes are governed by temperature and moisture and are modeled with separate equations for green, standing dead and litter. Dry conditions accelerate the maturation of live material, but slow the loss of digestibility of standing dead and litter. Seeds and seedlings are simulated only in annual species.
Germination depends on surface soil moisture and temperature.
Assimilation by seedlings is computed separately from assimilation by established plants because they are competitively inferior for light, have a smaller rooting depth and are more susceptible to death from stress. Potential intake is the amount that animals would eat on abundant, high-quality pasture. It is largely a function of animal breed and age, with lactating animals having higher potential intakes than non-lactating animals. Actual intake is then determined by considering the amount and quality of pasture available to the stock. Animals select a diet of higher quality than that which is on offer, and the effect of substitution of supplement for pasture is also taken into account.