Key Messages:

• Deep-rooted perennial legumes may help improve nutrient cycling and biological activity in low fertility sandy soils.
• Increased plant diversity through companion cropping and perennial systems can improve groundcover and reduce erosion risk.
• Soil amelioration, particularly clay incorporation, continues to show promising productivity benefits on deep sands.
• Establishing productive legumes on harsh sandy soils remains challenging and species selection is critical.
• Long-term monitoring is needed to better understand impacts on soil carbon, soil function and farming system resilience.

Project Background:

Deep sandy soils across the WA Wheatbelt are difficult to manage due to low fertility, poor water and nutrient holding capacity, and high susceptibility to wind erosion. Traditional farming systems with long summer fallows can further reduce soil organic matter and biological activity, limiting long-term productivity and resilience.

Growers are increasingly looking for farming systems that improve soil function while maintaining profitability. Perennial legumes, companion cropping and targeted soil amelioration may help increase groundcover, improve nutrient cycling, stimulate biological activity and support more resilient production systems on challenging sandy soils.

Project Summary:

This long-term Soil CRC project, delivered in partnership with Murdoch University and local growers, is evaluating plant-based approaches to improve the performance of infertile sandy soils in mixed farming systems.

Field trials established in the eastern Wheatbelt compare a range of management strategies including:

• perennial pasture legumes,
• companion cropping and intercrops,
• soil disturbance and clay amelioration,
• conventional annual systems.

The project is investigating how these approaches influence:

• soil biological activity and rhizosphere processes,
• soil carbon and nutrient cycling,
• groundcover and erosion risk,
• crop establishment and productivity,
• whole-system resilience and profitability.

Research sites at Bullaring and Harrismith are helping identify legume species and farming system approaches suited to low rainfall, deep sandy environments.

Current Focus (2026):

In 2026, the project is continuing to investigate practical approaches for improving the productivity and resilience of deep sandy soils.

At the Bullaring site, the Bednar soil amelioration treatment has been revisited with a higher clay application rate to further investigate the long-term benefits of clay incorporation on sandy soil function and crop performance.

The site will also transition into a wheat and ryegrass phase managed as a green manure system, aiming to increase biomass production, groundcover and organic matter inputs while supporting soil biological activity.