Perennial Pasture Biennial Fertilisation Trial

  • BioAgPhos S10 produced 26.3% more dry matter than the control
  • BioAg Superb produced 20.7% more dry matter than the control
  • BioAgPhos S10 produced 8.9% more dry matter than SSP

Dadswell Bridge Pasture Trial Report

Trial Aim

Compare the efficacy under replicated field trial conditions of various fertilisers when used on a biennial (every second year) application rate and schedule. The trials main aim is to ascertain which (if any) of the fertilisers best maintains production in the second year.

The Dadswell Bridge Trial site is located in the Wimmera Region of western Victoria (Australia).


The Dadswell Bridge area is located in the Wimmera region of western Victoria (Australia).

The common practice for pasture fertilisation in this region is to apply periodically e.g. on a biennial schedule (every second year).

The aim of this trial is to mirror this practice, and test which fertilisers perform best using biennial rates and application schedules.

While a year one response is important, the trials main aim is to ascertain which (if any) of the fertilisers can best maintain production in the second year.

Fertiliser application rates for pasture in this area is typically low, which is reflected in the trial.


Products Trialled

Trial years 2015, 2016
Fertiliser applied 2015 only
Treatments 5, Replications 3
Plot size 1m x 5m

Single superphosphate (SSP)
BioAg Superb
BioAgPhos S10

Site Characteristics

pH 6.7 (water).
Clover/phalaris pasture mix.
Low sulphur – 4.6 (15 is desirable).
Moderate phosphorus – Colwell 30 ppm (35ppm desired).
High iron. Reasonable cation balances.
Applied at a biennial (every second year) application rate.
Application rates based on an average annual spend of$28/ha (excl. freight, spreading and GST).

Summary Results


Fertiliser was applied in this year only.

2015 was a very dry season, with very low levels of dry matter produced across all plots.

The best response came from sites applied with fertiliser that contained sulphur in a sulphate form (SSP and Superb).

The two sites produced similar dry matter yields.

The likely reason for this is the sulphate form of sulphur in these two products requires less rain before the sulphur becomes plant available.


No additional fertiliser was applied.

2016 was wetter than average, and dry matter production was greater for all plots compared to 2015.

Also in 2016 we saw the greatest difference in dry matter production between the plots.

In 2016 the BioAgPhos S10 plot deliveredsignificantly higher dry matter than all other plots.

The next best dry matter production was from the BioAg Superb plot, and then the SSP plot.

Sulphur availability again stood out as a likely factor in production, with all three applications that contained sulphur delivering highest dry matter production.

In addition, the plots applied with sulphurcombined with sustained release phosphorus outperformed plots using water soluble P and S.

When compared to the control plot, BioAgPhos S10 grew almost 3 t/ha more dry matter.

Total Production



BioAg Superb and SSP produced the most dry matter, with negligible difference between the two results (3,770 and 3,802 kg/ha of dry matter production respectively).

Dry matter production was low for all products on trial with 309 kg/ha separating the best from the worst performance.

Low dry matter production was a result of the very dry season experienced in 2015 in this region.

Both BioAgPhos S10 and Superb plots outperformed SSP in the production of dry matter.

S10 produced the most growth (10,323 kg/ha), with Superb (9,631) and SSP (9,070).

S10 produced almost double the additional production than SSP when compared to the Control, and around 700 kg/ha more than Superb.


BioAgPhos S10 followed by BioAg Superb delivered more dry matter in both the second year, as well as in total across the two years.

While seasonal conditions impacted the overall dry matter production for every treatment, it is evident that the availability of sulphur and a sustained release form of phosphate (as delivered by BioAgPhos S10 and BioAg Superb) produced greater production across two years.

More Information

Trial Manager: Daniel Hill
Bachelor of Applied Science (Agriculture, University of Melbourne)
Fertcare accredited (Level C)
Mobile: 0448 453 412.