Optimizing fertility in ‘fragile’ soil

By Nicola Cottam

- Last updated on GMT

The Soil Biology Initiative II team in Western Australia - Pauline Mele pictured (second from left) Photo Credit: Sally Thompson
The Soil Biology Initiative II team in Western Australia - Pauline Mele pictured (second from left) Photo Credit: Sally Thompson

Related tags Soil

Australian scientists have developed a soil fertility test that should help farmers increase profitability and sustain grain production.

Under the Soil Biology Initiative II (SBI II) – a jointly-funded by the Australian government, research organisations and the grains industry, including the Grain Research and development Corporation (GRDC) – scientists have developed a method to test soil composition and fertility.

Using research compiled over five years - from 2001-2006 - they have refined a testing method and secured a better understanding of soil conditions across the country. The team used advanced DNA technologies, such as ‘omic’​ gene technology (chemical trait analysis), to identify potential biological, chemical and physical soil constraints to plant production.

Pauline Mele, lead scientist and project co-ordinator, said: “The project has provided us with evidence-based findings to support recommendations for improving soil quality. We are in the process of validating a new test that farmers can use to describe the condition of their soils and make appropriate adjustments to optimise soil fertility​.”

Fragile, vulnerable soil

Mele told Milling & Grains the research had shown the fragility of Australian soils. Soil organic carbon, for example, was typically less than 1%, compared to 5% elsewhere in the world.

“The wheat belt in Western Australia poses a particular challenge for growers due to the nutrient-poor sandy soil, which is also vulnerable to erosion and sub-soil acidity.”

Soil analyses had also exposed the detrimental effects of conventional fertilizers in suppressing beneficial microbial processes and the importance of adding organic matter to suppress root lesion nematode, which leeches valuable nutrients from plant roots.

“We are developing biomarkers of disease suppression and management techniques to encourage the build-up of these biomarkers to reduce disease. Sample evidence has shown that around 12% of sites studied have disease suppression potential.”

Boosting grower confidence

A key part of SBI II is sharing these scientific findings with growers using an online monitoring tool to give them the confidence to implement measures to stabilise yields and offset the effects of unpredictable market and environmental conditions, continued Mele.

“The 10-year drought in the 90s had a significant impact on grain- and particularly wheat - yields and the level of increase hasn’t improved as expected. In addition, Australian farmers don’t have the benefit of subsidies like other countries and are therefore more vulnerable than most to the volatile effects of fuel and fertilizer costs that affect profits.

“SBI II is a strategy to increase margins; reduce inputs and decrease costs, and generally improve the long-term health of the soil.”​ 

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