Nutrient loss risk assessment tools
When completing your farm plan, you will need to include a nutrient budget or nutrient loss risk assessment. Tools available for this are list below, along with their terms of use.
Nitrogen Risk Scorecard
The Nitrogen Risk Scorecard (NRS) is made up of:
- Nitrogen Risk Scorecard (NRS) - is used to determine the management practices on farm that have a higher risk of nitrogen loss. It is specific to nitrogen and looks at intensity and thus the risk associated with a certain management practice.
- Each management practice is assigned points under the NRS depending on how it is being carried out or its intensity, and this is further modified by looking at the sub-practices that increase or decrease the risk. The points allocated to each management practice can be aggregated to give an overall score.
The Scorecard has been developed for use as an automated tool which provides a simplified assessment of the N loss risk from a farm. The Scorecard engine assesses annual farmer data submitted through the Farm Dairy Records and applies a level of risk against a set of benchmark parameters to each of the six key farm management practices:
- stock management
- nitrogen fertiliser
- imported feed
- cropping and cultivation
- effluent management
- irrigation
OverseerFM
OverseerFM uses a set of sub models and components that work together to analyse the impact of farm management on the flow of nutrients through the farm system. It generates output loss numbers for key farm nutrients of concern – nitrogen and phosphorus.
OverseerFM models the movement of nitrogen on the farm based on farm management practices. This includes estimating the nitrogen lost below the root zone (60cm) for individual blocks and the farm as a whole. OverseerFM does not account for all attenuation of nitrogen and therefore does not model how much nitrogen ends up in waterways.
Like nitrogen, OverseerFM models the movement of phosphorus on farm. This gives an idea of how well available P is used to generate produce and the amount lost as typical runoff. Because OverseerFM relies on entering reasonable information about P levels in the soil over time, soil tests are important to help assess the movement of this important nutrient.
The data inputs required by OverseerFM are readily available for most farmers. Using OverseerFM requires a good understanding of the farm system to ensure the inputs used are realistic and representative of the farm operation.
The nutrient budget from the OverseerFM model describes how nutrients cycle on blocks or across the whole farm. The key output from the model relevant to your farm plan is the quantitative loss of N and P to water. Budgets are provided at both block and farm level. Higher loss blocks should be analysed to see what might be contributing to the losses and whether any changes to management might affect the results.
