Deer and environment: Overseer® upgrade

Recent upgrades to the nutrient budgeting programme Overseer that affect environmental outputs for deer farms include: the deer intake model, which can influence nitrogen leaching losses; phosphorus losses from areas affected by wallowing and fence-line pacing; and, the greenhouse gas emissions database. In addition, farm blocks within Overseer are tested as sub-catchments (e.g. a group of paddocks 10-20 ha in size) within a farm as a “basic” spatial management tool to determine the likely areas at risk of contaminant losses (e.g. nutrient losses to water). Data were sourced from 10 deer-farmed sites in Otago and Southland representing the following scenarios: winter forage cropping, finishing and weaning blocks, fence-line pacing, wallowing and wetlands. Overall, the model predicted 87% of variation in phosphorus (P) losses (P<0.05), but this was based on limited data. Additional data will be incorporated when available. The recent upgrade of Overseer gives farmers a tool to see how deer affect environmental outputs at a farm and possibly, sub-catchment, scale.