An economic evaluation of high nitrogen fertiliser rates at Limestone Downs

Increased nitrogen application has potential to achieve “step change” in forage production and productivity of hill country properties. This paper reports the results of a financial evaluation of high rates of nitrogen at Limestone Downs where the farms management have experienced difficulty in meeting sheep and cattle feed requirements in late winter and spring. High rates of nitrogen (250kg N/ha in split dressings) were applied from June to September and pasture responses measured by Agresearch®. In the first year of the study large (19 kg DM/kg N) responses were achieved to applied N, and in the second year 11 kg DM/kg N within 90 days of application. The financial performance of the system was evaluated by monitoring of the whole farm system using the simulation model Stockpol®. Evaluations were completed across a four-year period, including two years prior to the application of high nitrogen rates, the transition year and for the new farm system operating at a sustainable level.