Farming for the Future. Optimising soil health for a sustainable future in Australian broadacre cropping

By definition, sustainable and successful farming businesses depend upon the health of their soils. For many years, conventional farming practices have been degrading soils, creating issues such as erosion, and negatively affecting crop yields. Full-disturbance tillage of the soil and whole paddocks left bare to fallow, goes against the laws of nature. A recent shift in farming practices towards minimum tillage has seen many benefits –yield increases, reduced erosion, improved cover retention and better water infiltration to name a few. The zero-till revolution has been paving the way for the agricultural industry to further improve management practices, in a push towards biomimicry.

The findings of this report indicate that farming in nature’s image is increasingly important to maintaining soil health in agricultural operations. Bio-diversity and groundcover retention are both key elements to obtaining optimal soil health. Multi-species cover cropping is an emerging innovation in soil health management proving to be extremely effective at incorporating both of these elements.

This report reviews the functions of multi-species cover crops as ground cover for weed suppression, erosion prevention, increasing soil organic matter levels, and improving water infiltration and moisture retention.

It also investigates the effects of bio-diversity on soil function, with an analysis of the significant interactions provided, including microbial activity, the bacteria to fungi ratio, the carbon to nitrogen ratio, and carbon and nutrient cycling. Key findings indicate that the species-richness effect on soil health is predominantly related to root biomass production, which stimulates growth and diversity in microbial communities within the soil, balances the bacteria to fungi ratio, and generally creates synergy between all soil elements and processes to promote a healthy soil ecosystem.

The logistics, considerations and financial viability of incorporating multi-species cover crops into broadacre cropping rotations is also assessed. Research shows that despite initial financial deficits being possible in early cover-cropping seasons, the long-term soil health benefits prove to be profitable through increased yields and decreased costs on fertiliser and chemical inputs.