Condensed tannins accumulation and nitrogen fixation potential of Onobrychis viciifolia Scop. grown in a Mediterranean environment.

BACKGROUND: Sainfoin (Onobrichis viciifolia Scop.) is a forage legume present in temperate areas and less widespread in Mediterranean environments. Compared to other perennial legumes, it has the advantage of containing condensed tannins (CT) that can be important for their implications on nutrition and health of ruminants. Sainfoin nitrogen fixation data reported in literature about sainfoin originate from very different environments and only few field data are available, so it is important to deepen knowledge about N fixation potential of such species, particularly under Mediterranean climate. We studied the accumulation pattern of polyphenolic compounds (total, non tannic polyphenols and CT) and the nitrogen fixation potential of sainfoin in order to contribute to the valorisation of the species for sustainable farming management in Mediterranean environments. RESULTS: CT concentrations were always in the range considered beneficial for animals, not exceeding 50 g delphinidin equivalent kg-1 . The regression of the aerial fixed N on the aerial dry matter (DM) showed, in Mediterranean environment, a relationship of 22 kg of fixed N per tonne of aerial DM. CONCLUSIONS: A wider exploitation of sainfoin is suggested for production under rainfed conditions, thus enlarging the limited set of available perennial legumes suitable for Mediterranean environments.