Using nitrogen to boost pasture supply

When soil moisture is not limiting plant growth, the response of pasture to nitrogen will depend on the pasture’s underlying growth rates. The potential growth rate of pasture is primarily determined by temperature and the amount of sunlight being captured by the plants. 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.

Four factors should be considered in nitrogen application decisions:

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

It is important to remember that predictable responses to nitrogen are only found when applying more than 30 kg N/ha (65 kg Urea) and less than 50 kg N/ha (110 kg urea) per application.

More info...

For more info, check out the nitrogen fact sheet, in particular the 'decision making' section on page 2.