Managing Nitrogen in Winter Pastures

The challenge of maintaining Winter pasture production

Volatilisation occurs when ammonium in urea converts to a gas. This can lead to significant N losses when using urea.

Maintaining pasture productivity through the cold and wet months of Winter and early Spring, underpins the productivity and profitability of all pasture systems across southern Australia.

Whilst the traditional approach of 2-3 applications of granular urea has typically provided dry matter production, we know the efficiencies are not there.


>36% of surface applied nitrogen lost

Table 1: The potential volatilisation losses from urea after Autumn and Winter applications.

Published in the ‘Australian Soil Fertility Manual – CSIRO’ we can see just how ineffective granular urea can be through the Winter months.

It also shows that sulphate of ammonia (SOA) is the better option to supply nitrogen to growing pastures.


The value of SOA with nitrogen

There are numerous trials that show the value of sulphur to growing pastures, so we shouldn’t underestimate the value of the sulphur component from the SOA.

We know that sulphur is involved in the formation of amino acids and consequently protein.

We also know that sulphur is leached from our soils during periods of high rainfall.

Combining sulphur with nitrogen for all Winter applications just makes good agronomic sense.


Winter foliars

BioAg designed its foliar feeding programs to alleviate the nutrient availability and leaching issues stemming from the cold, wet soils of Winter.

These programs include nitrogen and sulphur, and are now successfully used by a number of our dairy customers, as well as in other crops and pastures as part of the overall nutrition program.

This approach not only supplies the nitrogen and sulphur that we know is required by pastures during the Winter months, but it also supplies:

  • vitamins
  • minerals
  • proteins
  • amino acids
  • carbohydrates
  • plant hormones

These are ingredients that the plant requires for a variety of reasons, including converting nitrogen and sulphur into true plant proteins.

Whilst the foliar program is tailored to suit each grower, the basis of the program is;

  • Balance & Grow – 2 l/ha
  • Sulsa or UAS – 30 l/ha


What does a user of this type of program say?

Feedback from Victorian based dairy farmer and user of this type of program:

“Anyone can grow grass in Autumn and Spring just by throwing nitrogen at them.

Where this system stands out is its ability to grow quality pasture from June to August.

High protein and high ME feed is what keeps your milk volume and components up”.