Can the inclusion of ribwort plantain or chicory increase the seasonal and annual dry matter production of intensive dairy grazing swards?

Pasture species complementarity leading to increased dry matter (DM) production has been observed in multispecies (MS) swards which include legumes and forage herbs along with grasses. This effect has been measured in mechanically defoliated plots with little data available from grazing scenarios. There is a scarcity of data available regarding individual forage herb species contribution to increased sward DM production where only plant functional group has been monitored previously. The objective of this three year study was to assess the DM production, N fertiliser response and change of botanical composition in grazed plots across nine MS sward mixtures compared to a PRG monoculture. Multispecies swards included various combinations of species from the three plant functional groups; N fertiliser treatments of 0, 100, 150 and 200 kg N/ha/year were applied. While year influenced the effect of sward mixture on annual DM production, swards that included white clover (Trifolium repens. L.) produced an average of 1688 kg DM/ha/year more than those which did not (P < 0.05); including forage herbs did not increase either annual or seasonal sward DM production. In the final year of the study sward chicory (Chicorium intybus. L.) content was 5% in mixtures including three plant functional groups while ribwort plantain (Plantago lanceolate. L.; PL) content was 37% in the same sward types. Although PL did not increase grazed sward DM production in the current study it did persist well under grazing and may provide other beneficial ecosystem services in dairy grazing systems.