The GrassGro decision support tool: its effectiveness in simulating pasture and animal production and value in determining research priorities

The GrassGro decision support tool combines animal intake and nutrition models, soil moisture and pasture growth models with management rules. GrassGro simulates pasture and animal production using a wide range of pasture species and sheep and cattle enterprises. Data from the Temperate Pasture Sustainability Key Program grazing management sites were used to validate the predictions of GrassGro. The pasture and animal production from a diverse range of sites were successfully simulated. Limitations of GrassGro were identified (parameter sets not available for some pasture species, inability to simulate clumpy swards, rudimentary interspecies competition model) and some improvements were made to its performance (improved species parameter sets and improved modeling of rooting depth). Recommendations are made on priority areas of research to improve GrassGro and on improvements in methodology which could be adopted by future programs like Temperate Pasture Sustainability Key Program.