Abstract
1. A study has been made of some of the factors influencing the role of clover in grass-clover swards fertilized with nitrogen at different rates.2. From 1955 to 1957 inclusive three nitrogen treatments, 0, 4 and 10 cwt. ‘Nitro-Chalk’ (15·5% N)/acre/season, were applied to twentyone grass-clover mixtures sown in the spring of 1954. The mixtures contained either S 184, S100 or Kersey white clover alone or in association with one of the following grasses, S 23 or S 24 perennial ryegrass, S143 or S37 cocksfoot, S48 timothy or S53 meadow fescue.