Managing non-wetting sands a success in South Australia through MLA project
A project between Meat & Livestock Australia (MLA), Coorong and Tatiara district council and Soil Function Consulting is looking to improve grazing production on non-wetting sands in the Upper South East of South Australia.
Non-wetting sands, also known as hydrophobic sands or water-repellent sands, are types of sandy soils that exhibit a strong resistance to wetting or water infiltration. Unlike typical sandy soils, which readily absorb water, waxy coatings cause non-wetting sands to repel water and do not allow it to penetrate easily.
Principal consultant Dr Melissa Fraser from Soil Function Consulting said the strategies aim to treat common constraints, such as water repellence, compaction and poor nutrient fertility to grow more pasture.
“It will also aim to maximise rain-fed soil moisture and fertiliser use to reduce the overall cost of production per hectare, as well as increasing livestock productivity and performance,” Dr Fraser said.
In 2022, an 24ha pasture paddock at a property called ‘Booderoo’ near Coomandook, SA, was selected to demonstrate strategies to overcome sandy soil constraints that had hindered the paddock.
Once the soils were tested and their constraints known, contrasting deep tillage and mixing were implemented to improve the soil.
“Nutrient deficiencies should also be addressed in the summer to autumn period,” according to Dr Fraser.
“Composts applied on the surface after mixing may help to stabilise the soil and boost pasture growth.”
“Being in a winter rainfall-dominant region, the ideal time for producers in southern regions to complete tillage, mixing and sowing is mid-March to mid-April,” Dr Fraser said.
Cereal rye, vetch and grazing brassica were chosen as the forage crop due to its reliability and ability to flourish in low-fertility, deep sandy soils. Following the first year of treatment, the cereal rye was harvested for seed and was grazed for the third time over the 2022–23 summer.
According to Dr Fraser, the Booderoo property found successful results in treating its non-wetting sands and they’re now looking for other producers to help test similar techniques.
“Producers can assess their pastures for water repellence by following the guidelines at the newly launched Coorong Tatiara Soil Hub website,” Dr Fraser said.
“The website will provide growers and advisors with information, resources, and tools to support improved agricultural and economic outcomes across the Coorong and Tatiara Districts.”
“There are also upcoming workshops and demonstration site visits at Coomandook and Willalooka on 28 September and 18 October respectively, producers looking to get involved can find more information on the website,” Dr Fraser said.
According to Mitchell Plumbe, Project Manager – Adoption Southern & Western Production Systems at MLA, the Improved Grazing Production on Non-Wetting Sands Project targets a large area of sandy soils across the Coorong and Tatiara regions that are strongly water repellent.
“The objective of the project is to improve participants’ understanding and increase adoption of viable soil amelioration practices to improve fodder and livestock production,” Mr Plumbe said.
“The practices being trialled in the project have been developed in the cropping industry, we are applying them and validating cost efficiency in a grazing system.”
“The project is measuring the impacts of a range of mechanical and chemical soil amendments across three demonstration sites with the aim of validating and demonstrating viable techniques to improve soil fertility and function, optimising the utilisation of soil moisture to boost feed production and carrying capacity.
“Promotion and uptake of the successful treatments will improve sustainability and growth of livestock production systems across various regions of southern Australia that experience limitations from non-wetting sandy soils.”
