Fig. 1. Total DM (a) and yield (b) during regrowth of perennial ryegrass swards from 21 July to 15 Sept. 1997 at ambient (36 Pa) and elevated (60 Pa) pCO₂ and after an infrequent (4 cuts yr^-1) and frequent (8 cuts yr^-1) cutting treatment before the beginning of the experiment. Necromass in (a) and (b) not included (Error bars = SE, n = 6).