Does the Inclusion of French Serradella ( Ornithopus sativus Brot.) Enhance Productivity and Resilience of Pastures in Low‐Rainfall Mixed Farms in N

ABSTRACT

French serradella ( Ornithopus sativus Brot.) is an annual pasture legume typically grown on acidic soils, but its potential for production in low‐rainfall, neutral to alkaline sandy soils of southern Australia is poorly documented. A series of experiments across low‐rainfall mixed‐farming regions assessed the adaptive advantages of French serradella relative to other annual pasture legumes grown in crop‐pasture rotations. Measurements included above‐ground dry matter (DM) production, groundcover, seed yield, nitrogen fixation, herbage quality, and suitability for dry sowing. French serradella showed strong adaptation to deep sandy soils across a pH range of 5.5 to 7.8, achieving groundcover, forage quality and nitrogen fixation rates comparable with most improved annual pasture legumes. Its resistance to powdery mildew limited the extent of this disease in pasture mixtures containing annual medics. Across landscape positions, French serradella dominated the dunes, showing a preference for light‐textured, deep sands with a neutral pH, in contrast to annual medics ( Medicago spp.) that dominated the alkaline, finer‐textured mid‐slopes and swales. Serradella's deeper rooting system and responsiveness to late‐season rainfall allowed longer persistence in the season than shallow‐rooted annual Medicago species. Serradella and a strand medic cv Seraph (sown as mixed pastures) regenerated from soil seed banks following grain cropping, highlighting the persistence and significance of these species in ley farming systems. Dry sowing of serradella pods was most effective in soils where compatible rhizobia were already established from prior lupin cultivation and when sowing coincided closely with rainfall events, indicating higher rhizobia survival. Our findings indicate that French serradella can be a complementary or an alternative pasture species to subterranean clover and medics, particularly in sandy and low‐rainfall mixed farming systems, depending on soil constraints. However, further work is required to refine inoculation strategies, pasture mixtures and grazing management and to evaluate the reliability of responses under variable environments.