DPIRD researchers have been looking to overcome the challenge of farming white gum gravels at Yarrabin Farm using a combination of soil amelioration and crop rotations, with encouraging results.
The team was presented with highly compacted loamy gravel soil that was water repellent and had high levels of root lesion nematodes and Rhizoctonia solani AG8.
Field day presentations will discuss the field experiments located at the current site and a Grains Research and Development Corporation (GRDC)-supported field site near Darkan.
They will also more broadly cover suitable soil amelioration options, the properties of gravel stones, soilborne diseases, nematode pests and weed management on gravel soils.
DPIRD plant pathologists Sarah Collins and Daniel Hüberli will discuss which soil amelioration styles can be effective for management of soilborne disease issues.
“We are looking across several sites at whether crop rotations ahead of soil amelioration influence crop performance, soil biology and the impact of soilborne disease and nematode pests,” Dr Collins said.
“At Williams, we grew four crops - canola, barley, narrow leaf lupins and serradella pasture - over two seasons to manipulate the soil biology, soil nutrients and potentially weed status.
“The site was then ameliorated in 2021, with three methods tested - deep ripping, mouldboard ploughing and one-way disc ploughing - followed by a barley crop across the whole site.
“Use of serradella or lupins as a preceding species resulted in a marked reduction in root lesion nematodes and improved barley grain yield from 3.6 tonnes per hectare for barley grown after a preceding barley crop to 5.4 and 5.7 tonnes per hectare (or a 50 to 58 per cent yield increase).
“Soil amelioration with the use of a mouldboard or one-way plough reduced the levels of Rhizoctonia solani and root lesion nematode P. quasitereoides and all of the amelioration types increased barley grain yield from 4.2 tonnes per hectare for the non-ameliorated control to 5.0 to 5.1 tonnes per hectare (19 to 21 per cent).”
Dr Collins said an unexpected result they had observed in related research on a sandy loam site at a GRDC-supported research site at Yerecoin, was that soil biology appeared to improve post amelioration of severely constrained soils.
“We are looking at the soil biology as an indication of soil health. Results show that when you have significant soil constraints, the soil health is improved by ameliorating the soil,” she said.
“We didn’t expect this, we thought the microbes could get damaged by the soil disturbance and take time to recover.”
Along with leading DPIRD researchers, speakers also include Ken Flower, of The University of Western Australia, who will discuss agronomy and potential crop rotation and Francesca Brailsford, of Murdoch University, talking about the characteristics of gravels and the implications of this on nutrient availability.
The field day runs from 9am-3.30pm, Wednesday 14 September at Yarrabin Farm, Williams.
