Seasonal variations in nutritive and botanical composition properties of multispecies grazing swards over an entire dairy grazing season

• Published in: Grassland research (Online) 2022-12, Vol.1 (4), p.221-233
• Main Authors: Hearn, Ciarán, Egan, Michael, Lynch, Mary Bridget, Fleming, Christina, O'Donovan, Michael, Hou, Fujiang
• Format: Article
• Language: English
• Subjects: Abundance; Binary mixtures; botanical composition; chemical composition; Clover; dairy production; Digestibility; Grazing; Herbs; Legumes; Lolium perenne; Monoculture; multispecies swards; Nitrogen; Nutritive value; Pasture; Seasonal variations; Seasons; Species; Sward
• ISSN: 2097-051X; 2770-1743
• DOI: 10.1002/glr2.12037

Background Recently, there has been increasing interest in the use of multispecies (MS) swards in dairy grazing systems. Methods A plot grazing study was established to investigate the potential contribution of different sward species (perennial ryegrass, legumes and herbs) sown in grazing pastures. Ten sward mixtures were sown, ranging in complexity from a perennial ryegrass (PRG) monoculture to binary mixtures including either forage legumes or herbs to a five‐species mixture; four different nitrogen (N) application rates of 0, 100, 150 and 200 kg N ha−1 were applied to each sward. Results Species abundance for all sward species components was associated with the interaction of time point and sward mixture; species abundance for all sward components, except PRG, was associated with the interaction of N application and sward mixture. The interactions of time point and sward mixture, and time point and N application rate, were associated with all analysed sward chemical components, except for sward digestibility. Conclusions Increased N application rates reduced the level of clover in all sward mixtures. Increased levels of white clover led to increased sward crude protein levels; the inclusion of ribwort plantain led to some seasonal variation in the nutritive value of swards. There was an effect of sward species mixture on sward crude protein (g kg−1 DM) across all nitrogen application rates. Results indicate that white clover has a significant influence on sward protein content; this is further influenced by the growth habit of white clover over the course of a growing season.