Productivity of Lotus corniculatus L. (bird's-foot trefoil) in the UK when grown under low-input conditions as spaced plants, monoculture swards or mixed swards

The dry‐matter productivity of the forage legume Lotus corniculatus (bird's‐foot trefoil) was assessed under low‐input conditions at three sites in the north of England. An initial study in 1989 and 1990 compared fourteen accessions of L corniculatus with Trifolium repens and T. pratense grown as spaced plants at two sites with contrasting soil conditions. One site represented good agricultural land, the other poor‐quality, marginal land. Yields of all species and accessions were significantly lower on the marginal site. Seasonal yields (averaged over sites) of L corniculatus cultivars averaged 52 g plant−1 and 170 g plant−1 in 1989 and 1990 respectively. General trends over both seasons were that T. repens and T. pratense yields were high but some L. corniculatus cultivars (Empire, Franco, Leo) and naturalized UK ‘aliens’ were similar to at least one Trifolium in each year. Yields from L. corniculatus ecotypes from the UK and Norway were very low in comparison with the cultivars. A largerscale study of eighteen L corniculatus, two L uliginosus, three T. repens and two T. pratense accessions was undertaken on an upland, calcareous site in 1990. Legumes were assessed in 2 m × 2 m swards as either monoculture or grass/legume mixture. Establishment and productivity of L uliginosus and T. pratense accessions were poor, with seasonal yields no greater that 50gm−2 year−1. When grown as a monoculture, L corniculatus yields were superior to both Trifolium spp., and averaged 1080 gm−2. In mixed swards, L. corniculatus constituted a higher proportion of the total dry matter yield (26% and 62% at first and second cuts, respectively) than the other legume species. It is concluded from these studies that L corniculatus is suited to marginal or free‐draining calcareous soils under low‐input conditions, and consequently has more potential for use in the UK than has previously been reported.