Dr Stephen Davies and Chris Gazey from the Department of Primary Industries and Regional Development, Government of Western Australia, explain how grain growers achieve higher profits and resilience through the widespread adoption of soil management strategies
The dryland grain-growing region of southwest Western Australia (WA) spans nearly 16 million hectares of arable land, 75% of which is used for grain crops such as wheat, barley, canola, oats, and pulses. The region exports 80-90% of its grain, primarily to Asia and the Middle East, contributing 40% to Australia’s grain exports.
Grain production occurs in a water-limited environment with winter-dominant rainfall, but with a warming and drying trend. Despite a 10-20% decrease in growing season rainfall over the last 50 years, average wheat yields in WA have increased by 25% since 2010 due to advances in agronomy, crop genetics, and soil management strategies.
Approximately 70% of WA’s cropping soils are sandy, consisting of deep sand, sandy earth, sandy duplex, and sandy gravel. Soil amelioration practices, particularly on acidic sandy soils, include applying lime (such as lime sand or crushed limestone) and one-off or occasional deep soil mixing or inversion to address subsurface acidity. These practices bury water-repellent topsoil, improving surface wettability and seed germination.
Deep soil inversion can also reduce weed density by burying weed seeds, while soil loosening, using deep rippers often to a depth of 50 cm or more, addresses compaction.
The adoption of soil amelioration has been widespread, with two-thirds of WA grain growers using deep tillage by 2024, while 20% apply soil amendments without tillage. Fewer than 15% of growers practice no soil amelioration. The success of these practices is due to strong engagement between researchers, grain growers, and consultants, creating a proactive knowledge-sharing environment.
Research and extension programs
Soil management research, particularly on soil acidity in WA, has been ongoing for over 40 years. In the early 2000s, programs focused on compaction, controlled traffic farming, and subsoil constraints. In the 2010s, research expanded to address multiple soil challenges, including acidity, compaction, water repellence, and sodic soils. More recent programs also explore the interactions with biological constraints, such as weeds and soilborne pests, as well as the positive effects on beneficial soil fauna and microbiota.
Grower and consultant engagement
Active engagement with growers has been central to the success of soil amelioration practices. Field workshops with soil pits were widely used to educate growers about soil constraints and their impact on crop yields. Most research and demonstration experiments have been conducted on commercial farms, with growers playing a key role. Early adopters often shared their experiences with others, contributing to widespread practice adoption.
Growers and consultants have contributed valuable feedback to researchers, helping identify additional benefits and challenges of soil amelioration. This collaborative exchange has enhanced ongoing improvements in both research and implementation. The WA grains industry benefits from a strong culture of growers sharing knowledge and experiences to improve the industry as a whole.
Innovative tools and communication methods
Various communication and learning methods have supported the adoption of soil amelioration. Decisionsupport tools range from calculators and decision trees to phone-based apps like iLime, which helps growers compare lime sources and application methods. The Soil Quality e-book series, freely available on Apple Books, provides interactive learning on soil management topics and has proven valuable for educators, consultants, and growers.
Other communication efforts include soil management bus tours, machinery demonstration days, and workshops, in addition to the more common field walks and field days. These diverse approaches have played a crucial role in promoting soil amelioration practices.
Financial benefits and future opportunities
Crop yield responses to soil amelioration in WA typically range from 30-50%, and a recent analysis by consulting firms Farmanco and Planfarm found that grain growers who adopted the “amelioration package” had an average operating profit of $100 per hectare higher than those who did not. This profitability highlights the value of sustained investment in research, development, and extension (RD&E).
Continued funding for RD&E, through collaboration with the Grains Research and Development Corporation, not only promotes the adoption of effective soil management strategies but also supports the training of researchers and extension specialists. Engaging with growers on large-scale, diverse farms across vast geographic areas requires a substantial number of skilled professionals. Though this comes at a cost, the resulting crop productivity and sustainability improvements provide a significant return on investment, particularly as growers face the challenges of a warming and drying climate.
In conclusion, adopting soil amelioration practices in WA has delivered substantial benefits, including higher crop yields, improved farm profitability, and more sustainable grain-growing systems. Collaboration between researchers, growers, and consultants, along with the use of innovative tools and diverse communication methods, has been vital to this success. With ongoing research and engagement, the WA grain industry is well-positioned to continue thriving in the face of climate challenges.
Additional author: Chris Gazey, Senior Principal Research Scientist, Department of Primary Industries and Regional Development, Government of Western Australia.
