Dynamical systems modelling of the interactions of animal stocking density and soil fertility in grazed pasture

To examine the long term e ects of fertiliser application on pasture growth under grazing a mathematical representation of the pasture ecosystem is created and analysed mathe matically From this the nutrient application level needed to maintain a given stocking rate can be determined along with its pro tability Feasible stocking levels and fertiliser application rates are investigated and the optimal combination found along with the sensitivity of this combination It is shown that pro tability is relatively insensitive to fertiliser level compared with stocking rate