New metrics to quantify biological function and resilience in soils

Biological function in soils, such as nutrient cycling, C storage and turnover, water maintenance, soil structure and biotic regulation are integral for soil health and resilience. Such soil processes are critical for the sustainability of Australian agriculture and its interaction with overall ecosystem health at landscape scales. The capacity of a soil to withstand (resistance) and recover (resilience) from external stresses, including environmental, physical and chemical stresses, impacts system productivity and predicted climate scenarios will amplify these qualities. Understanding the limits and potential to improve both resistance and resilience of soil systems to stresses, remains a priority for research inquiry and for Australian growers and industry. A 'functional approach' to soil biological diversity and processes provides a potential method to measuring soil health and resilience. The prospect is increased understanding of the factors contributing to the resilience of soil function to different types of disturbances and provide markers for soil functional resilience. Implications to enduring effects from perennial crops, recovery from fallow phase and intensive cropping for complex functions (i.e., nutrition supply capacity, C sequestration and stability, and plant health) can only be investigated in longer-term system-based experiments. This opportunity exists with current regional GRDC Farming Systems investments to quantify how crop diversity (mix of different plant species grown) and crop intensity (the proportion of time plants are actively growing) influence the soils' biological function and resilience and demonstrate how more functional soil analytical approaches can quantify the current biological health of a soil. This project will provide foundational knowledge that will help Australian growers to better understand the relationship between agronomic management and soil health.