Spotlight on OVERSEER: perspectives and approaches to addressing nutrient management challenges using an integrated farm systems model

David Wheeler1, Caroline Read 2

1 AgResearch, Ruakura Research Centre, Hamilton, New Zealand, 3124, [email protected]

2 Overseer Management Ltd, PO Box 11785, Wellington, New Zealand, 6142

Abstract

OVERSEER® Nutrient Budgets (OVERSEER) is a whole-farm nutrient budgeting tool using a yearly time scale. It calculates a nutrient budget for the farm, taking into account inputs, outputs, and some of the internal recycling of nutrients around the farm. The model integrates multiple animal enterprises (dairy, sheep, beef, deer, dairy goats) and different land uses, including pastoral, cropping (arable, vegetable, fruit), and cut and carry areas. Nutrient budgets are calculated for the nutrients nitrogen (N), phosphorus (P), potassium (K), sulphur, calcium, magnesium, and sodium. With an increased emphasis on water quality, the model is being used to assess N leaching from pastoral farms. This paper discusses some perspectives and emerging practices that are occurring as a result of using an integrated farm systems model like OVERSEER, with a focus on urine patch, irrigation, effluent management and fodder crops.