"On-demand" hardseeded pasture legumes - a paradigm shift in crop-pasture rotations for southern Australian mixed farming systems

This paper presents a synopsis on the past 10 years of hardseeded annual legume research and adoption. Failure of traditional legume species such as subterranean clover (Trifolium subterraneum) and annual medics (Medicago spp.) in the medium and low rainfall zones of NSW and WA necessitated the development of crop-pasture rotation systems underpinned by more resilient legume species. Such species had been developed and included biserrula (Biserrula pelecinus), bladder clover (Trifolium spumosum), gland clover (T. glanduliferum) and French serradella (Ornithopus sativus cvv. Margurita and Erica). However, their use in farming systems was limited by lack of information on how to manage them and perceived high cost of establishment. The ability to harvest seed on farm using conventional headers and the unique hard seed characteristics of the new legumes resulted in development of the low-cost, one-time establishment options of twin and summer sowing. Robust rhizobia delivery technology was developed concurrently. Following establishment of the seedbank, new legumes can be used as an on-demand break option in the crop-pasture rotation as they, unlike traditional pasture legumes, do not need to be resown following each cropping phase. Additionally, legume species/varieties have significant potential for sustaining high levels of livestock production. Biserrula also has considerable potential in offering alternative control methods for the problematic cropping weed, annual ryegrass (Lolium rigidum).