Farmers inspect sorghum at the South Australian trial site. Source – GSSA.

NEW trials are testing the potential of different varieties of sorghum to improve summer fodder options for growers in south-east South Australia.

The replicated trial at Struan, south of Naracoorte, is designed to assess different sowing dates, the merits of three different sorghum varieties and the impacts of nitrogen applications.

The Grassland Society of Southern Australia Limestone Coast branch research project is titled `Improving the sustainability and irrigation use efficiency of summer fodder through improved management decisions’.

The project is funded by a Grassroots grant from Limestone Coast Landscape Board and supported by Barenbrug Australia.

GSSA Limestone Coast branch member and agronomist Adam Hancock said there hadn’t been sorghum trials in the region for more than a decade.

“We’re trying to see the yield potential from the new varieties of sorghum,” Mr Hancock said.

“It’s not a crop that we’ve had a lot of work done on for a long time.

“There are a few things that have changed over the decade, including the new varieties, we’re also sowing a lot earlier with the soil temperature at 13 or 14 degrees instead of 16,” he said.

“For southern parts, this could be a really big deal if we could get the crop in the ground three or four weeks earlier.”

Mr Hancock said plenty of trials now have shown that sowing into soils well before 16 degrees is very successful.

“Potentially the very earliest, but risky, is sowing when the soil is 13 degrees and rising.

“This takes some understanding; if you sow at 13 degrees and it drops then you can ruin your crop,” he said.

“The best bet is 14 degrees and rising unless you have soil probes on farm.”

The current trial site was sown twice 28 days apart to capture information about what earlier sowing could be worth to growers in south-east South Australia.

Variable nitrogen applications are also being tested.

“Because the yield potential is so much higher, we’re testing how much fertiliser you need to apply to capture your maximum yield potential.

“It could be anywhere between 18 and 30 (days) so we need to understand the ideal number,” Mr Hancock said.

The site has been zoned, with one area being cut once and another twice. A South Australian Research and Development Institute soil agronomy team is running the site and conducting the research.

The GSSA Limestone Coast branch hosted a field day on the site in February to raise awareness of the project. A further event is planned to outline the findings of the one-year project.

People interested in joining the GSSA can visit https://www.grasslands.org.au. Students can become members for free. GSSA has successfully promoted the business of grass, science and farming since 1959 and has branches in Victoria, South Australia and southern NSW.