Key points
Increased plant diversity in cropping systems typically increases soil microbial diversity, which in turn may be linked to improved soil function and farming system resilience.
Temporary cereal-legume intercropping in southern Australian grain cropping systems and cover cropping in tropical sugar cane farming are promising options for increasing plant diversity and maintaining productivity.
Summer cover crops have potential to be used tactically in southern Australian cropping systems, such as during wet seasons, but may not be suitable every season because their water use can affect subsequent winter crop yields.
The challenge
Southern Australian cropping systems and tropical sugarcane production systems rely on a limited number of plant species in their rotations. This limits the diversity of carbon (microbial food) inputs into the soil and therefore the diversity of soil microbial populations.
Increased soil microbial diversity is linked to higher soil resilience. Finding economically viable ways to increase the diversity of plants in the farming system is a challenge, given that the cash crops grown in the existing rotations are generally the most profitable and low-risk options.
The Soil CRC’s ‘Plant-based solutions to improve soil performance’ project (4.1.002) aimed to identify management options to increase plant diversity in the farming system, without vastly altering crop rotations and while also maintaining productivity.
Our research
Five long-term field sites were established to investigate the impact of different management practices on soil function and crop yields. Research topics included:
- Summer cover cropping in southern cropping systems
- Temporary cereal-legume intercropping in southern cropping systems
- Oilseed-legume intercropping in southern cropping systems
- Perennial legumes in Western Australian cropping systems
- Cover crops during the plough-out phase of sugarcane farming systems in the wet tropics
