Modelling of grazing systems at the farm level

A simplified description of a model of a grazing system suitable for implem entation at the geographical scale of the field or farm is described. The p rogress that has been made in the modelling of the sail, plant and animal p rocesses within grazing systems is described and research areas are identif ied where improvements in understanding are needed. Arguments are presented for the importance of developing grazing models at the farm scale and inco rporating them into decision support tools to aid research on rural land us e and to provide support in decision-making by farmers, and regional and lo cal government. Two examples of farm-scale decision support tools, HILLPLAN and LADSS, are described which will aid respectively tactical and strategi c decision-making at the farm scale. (C) Elsevier/Inra.