Perennial C4 grasses increase root biomass and carbon in sown temperate pastures

The addition of perennial warm-season C4 grasses to perennial pastures, may contribute to carbon sequestration, in addition to increasing production and stabilising seasonal variations. We quantified root biomass in three pasture mixtures after 3 years of growth: a conventional mixture of Festuca arundinacea, Trifolium repens and Lotus corniculatus, the conventional mixture + Paspalum notatum and the conventional mixture + Paspalum dilatatum. Root biomass and content of carbon were higher at 0-10 cm than at 10-30 cm depth for both summer and winter sampling dates in all samples. Mixtures with Paspalum had higher root biomass than the conventional mixture in summer. No differences were observed between the two species of Paspalum in root biomass or carbon. These results show that the inclusion of Paspalum species in these systems may potentially increase carbon soil carbon, although further research is required to evaluate the effect of other management practices.