Competitive forbs in high-producing temporary grasslands with perennial ryegrass and red clover can increase plant diversity and herbage yield

Summary

European agriculture focuses on increasing biodiversity. However, in highly productive temporary grasslands in grass / arable systems, the biodiversity is usually low. Three non-leguminous species have shown high competitive strength in temporary grasslands and ample possibility to increase biodiversity without compromising yields. In this experiment, we examined in detail the competitiveness and productivity of the three forb species: chicory (Cichorium intybus), ribwort plantain (Plantago lanceolata) and caraway (Carum carvi) grown in different proportions in mixtures including traditional grassland species: perennial ryegrass (Lolium perenne) and red clover (Trifolium pratense), with fertiliser application as an additional factor. Dry matter (DM) yield and botanical composition were measured during one complete growing season. Annual DM yields were mostly equal when forbs were included in the grassland mixture. However, a three species mixture composed of perennial ryegrass, red clover and ribwort plantain had highest yield potential, especially with fertilisation. Chicory and ribwort plantain showed high competitive strength in the mixtures. Grass gave considerable response to fertilisation, but no consistent trend was found in the forbs. In conclusion, we found positive effect of plant species diversity and fertilisation on the ability of grassland mixtures to produce higher herbage yield.