Project update: Derisking sowing trial in 2025

Work continues on Eyre Peninsula to ‘derisk sowing’ and achieve better establishment and yields with early sowing and in dry sowing conditions, with a trial being conducted on a grey calcareous soil near Poochera. The trial will test a range of herbicides across two different times of sowing – the first being just prior to ANZAC day and the second sown today (16 June) following a small amount of rain over the Mortlock long weekend.

The site is still pretty dry (Figure 1), with the first time of sowing just starting to germinate (Figure 2).

Figure 1. Time of sowing 1 trial plots sown 24 April 2025 at Poochera, photo taken on 11 June 2025.

Figure 2. Germinating seed of Tomahawk wheat sown at 75 kg/ha at 2cm deep at the Poochera trial site, photo taken on 11 June 2025.

The trial aims to demonstrate practices to reduce herbicide toxicity and increase plant establishment in early sowing situations; determine if we can increase the seeding opportunities and plant establishment using dry sowing compared to sowing at the break on challenging soils (in this case grey calcareous soil), and to determine if there are other measurable benefits to the farming system e.g. biomass production (for livestock feed), weed control and yield from early sowing.

The trial was sown with Tomahawk wheat @ 75 kg/ha, 2 cm deep. The herbicide treatments applied to the first time of sowing plots were:

1            Nil Control

2            Sakura 118 g/ha IBS

3            Overwatch 1.25 L/ha IBS

4            Prosulfocarb 3L/ha IBS

5            Mateno Complete 1 L/ha IBS

6            Mateno Complete Post-sowing 1 L/ha EPS

7            Trifluralin 1.8 L/ha + Metrabuzin 100g/ha

8            Trifluralin 1.8 L/ha + Avadex 500gm active at 1.6 L/ha + Sakura 118 g/ha IBS

AIR EP in conjunction with SARDI Minnipa Ag Centre have received funding from the SA Drought Hub to deliver the trial. Look out for more information and opportunities to visit the trial site throughout the season. Thanks to Elijah Luo, SARDI Research Officer for conducting the trials, providing trial details and photos.

For more reading, the report of the outcomes of the 2024 trials at Rudall and Pt Kenny are available on the AIR EP website project page: https://airep.com.au/research/de-risking-the-seeding-program/

Also check out a new case study of a couple of EP farmers that have adapted their fertiliser delivery systems to reduce fertiliser toxicity.