This Information Sheet focuses on the management aspects for the profitable use of nitrogen (N) fertiliser on dairy farm pastures in southern Australia. It highlights options that were evaluated and refined during the five years of the 3030 Project and includes information from other national research projects such as the ‘Greener Pastures’ and ‘Best Management Practices for N on Pasture’.

Key points

• Four factors should be considered in evaluating the economic value of a N fertiliser application:

1. N fertiliser cost ($/kg of N).
2. Pasture response to N fertiliser [kg of dry matter (DM)/kg N applied].
3. Efficiency of pasture utilisation (by harvesting or grazing) and cost ($/t DM) of the pasture consumed.
4. Cost of alternative feed ($/t DM consumed).

• Using N to produce feed that can be grazed directly rather than conserved is often the most cost-effective option.

• The response to N fertiliser is related to the underlying growth rate of the pasture; to see a response to N soil moisture should not be limiting.

• An average application of 1–1.5 kg of N/ha/day during the growing season is a reliable rule to optimise N use. 

• Predictable responses are only found when applying more than 30 kg N/ha and less than 50 kg N/ha per application.

• Even though pasture growth responses are lower in autumn than in spring, autumn N applications can be profitable due to the expensive feed the resulting pasture can replace.