PRODUCTIVITY OF LOTUS-CORNICULATUS L (BIRDS-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 (b ird's-foot trefoil) was assessed under low-input conditions at three s ites in the north of England. An initial study in 1989 and 1990 compar ed fourteen accessions of L. corniculatus with Trifolium repens and T. pratense grown as spaced plants at two sites with contrasting soil co nditions. One site represented good agricultural land, the other poor- quality, marginal land. Yields of all species and accessions were sign ificantly lower on the marginal-site. Seasonal yields (averaged over s ites) of L. corniculatus cultivars averaged 52 g plant(-1) and 170 g p lant(-1) in 1989 and 1990 respectively, General trends over both seaso ns were that T. repens and T. pratense yields were high but some L. co rniculatus cultivars (Empire, France, Lee) and naturalized UK 'aliens' were similar to at least one Trifolium in each year. Yields from L. c orniculatus ecotypes from the UK and Norway were very low in compariso n with the cultivars. A larger-scale study of eighteen L. corniculatus , two L. uliginosus, three T. repens and two T. pratense accessions wa s undertaken on an upland, calcareous site in 1990. Legumes were asses sed in 2 m x 2 m swards as either monoculture or grass/legume mixture. Establishment and productivity of L. uliginosus and T. pratense acces sions were poor, with seasonal yields no greater that 50 g m(-2) year( -1). When grown as a monoculture, L. corniculatus yields were superior to both Trifolium spp., and averaged 1080 g m(-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 o ther legume species. It is concluded from these studies that L. cornic ulatus is suited to marginal or free-draining calcareous soils under l ow-input conditions, and consequently has more potential for use in th e UK than has previously been reported.