Biophysical Simulation of Sheep Grazing Systems Using the SGS Pasture Model

The performance of farming systems models for grazed grasslands are seldom evaluated against comprehensive field data. aim this study was to evaluate the capacity a daily time step, grazing simulation model—the SGS (Sustainable Grazing Systems) Pasture Model—to simulate production and aspects sustainability. This completed by evaluating temporal changes in soil water balance, some major nitrogen (N) fluxes, as well plant animal using data from two large scale experimental sites with sheep. simulations were broadly agreement measurements. In cases where divergence occurred reasons apparent could be explained reference model structure or particular, showed good observed water, but poorer volumes runoff. simulated N leachate inorganic less measured outputs sensitive symbiotic biological fixation subterranean (sub) clover mineralisation organic matter, which not measured. Similarly, there variable results growth production. complexities simulating comparing observations values discussed.