The productivity of four forage legumes sown alone and with each of five companion grasses

Four legumes—white clover cv. Blanca, red clover cvs Violetta (diploid) and Hungaropoly (tetraploid) and lucerne cv. Europe—were established as pure‐sown swards and with each of five companion grasses: timothy cv. Timo, meadow fescue cv. Bundy, sweet brome cv. Deborah and perennial ryegrass cvs Talbot (diploid) and Barlatra (tetraploid), both ryegrasses being of ‘intermediate’ heading date. Two ‘silage’ crops and an ‘aftermath grazing’ crop were harvested in each of three successive years. In the first harvest year, total herbage DM production of red clover ranged from 15·03 to 17·01 t ha^‐1. White clover and lucerne swards produced considerably less at 7·12 to 11·01 t ha^‐1. In the second harvest year, lucerne swards were the highest producing at 15·54 to 17·14 t ha^‐1, while DM production from red clover and white clover swards ranged from 6·75 to 11·87 t ha^‐1. Lucerne swards maintained their production superiority in the third year at 16·48 to 17·87 t ha^‐1, while production from white clover swards ranged from 6·41 to 10·23 t ha^‐1. However, red clover swards declined to 3·30 to 5·81 t ha ^‐1; this above‐average decline was mainly caused by the onset of red clover necrotic mosaic virus which affected all red clover plots uniformly in the second harvest year, and by winter conditions before the third harvest year. Total herbage DOM and CP yields of the swards were influenced in a similar manner to DM production.