GrazeGro: a European herbage growth model to predict pasture production in perennial ryegrass swards for decision support

GrazeGro, a herbage growth model, was constructed for use in a decision support system (DSS; GrazeMore) [Mayne C.S., Rook A.J., Peyraud J.L., Cone J., Martinsson K., Gonzalez A., 2004. Improving sustainability of milk production systems in Europe through increasing reliance on grazed pasture. In: Proceedings of the 20th General Meeting of the European Grassland Federation, Luzern, pp. 584-586] for pasture management in dairy production systems throughout northwest Europe. The model was based on the existing LINGRA (LINtul-GRAss) model [Schapendonk, A.H.M.C., Stol, W., Van Kraalingen, D.W.G., Bouman, B.A.M., 1998. LINGRA, a source/sink model to simulate grassland productivity in Europe. Eur. J. Agron. 9, 87-100], redeveloped and calibrated to meet the specification requirements of the GrazeMore project. Validation of the model from independent historical European data showed that model predictions were sufficiently accurate to make it a useful aid for on-farm decision-making processes. However, further parameterisation and validation would be useful for locations where the model will be operated using well-monitored swards under realistic parameters. In a local setting where growth data were monitored well, model precision was high. Although further development of the model is possible, currently confidence in effective grass growth predictions is good and GrazeGro is considered suitable for a decision support application.