Type of grass influences clover proportion and production of grass-clover leys

Inclusion of red clover (Trifolium pratense) in grasslands improves productivity. However, poor persistence, particularly under high fertilization rates, is a major limitation for wider utilization. Earlier observations indicated that the type of grass may influence the grass-clover balance, besides, e.g. cutting strategy. In a field experiment we investigated clover proportions and production of five different grass mixtures in combination with red and white clover (T. repens): (1) Lolium perenne; (2) L. boucheanum + L. perenne; (3) Festulolium + L. perenne + L. boucheanum + Phleum pratense subsp. pratense; (4) L. perenne + Festulolium; (5) Festuca arundinacea + P. pratense. The experiment was carried out for three years at two locations (sandy and clay soil) at high fertilization levels (254 and 306 kg N-total ha‑1 year‑1 from animal manure). Results indicate that red clover can be relatively persistent, with an average of 43% red clover in the DM-production in both the second and third year. Mixtures containing L. boucheanum showed significantly lower clover proportions. Protein production per hectare was strongly and positively related to the red clover proportion in the sward. These results show that grass species influence the productivity and clover proportions in grass-clover swards. The best performing mixtures under the given conditions include Festulolium or F. arundinacea.