Seven varieties of white clover (Trifolium repens L.), of varying leaf size from large to small, were sown with perennial ryegrass (Lolium perenne L.) in 1985, at an upland site, and compared over three harvest years under a cutting management (5-6 cuts), and under continuous grazing by sheep. Fertilizer N input totalled 80 kg ha" ' in both the cutting and the grazing trial. The same varieties were included in two official National List (NL) trials sown the same year at a nearby site; these comprised a yield trial with 6-7 cuts and a persistency trial mown very frequently (17 cuts) to simulate intensive grazing.At the upland site the large-leaved varieties, Milkanova and Blanca, were the highest yielding under cutting (mean 3-3 t DM ha"'), and the small-leaved SI84 and Kent the lowest yielding (mean 2-3 t DM ha~'). The rankings were reversed under grazing (corresponding yields 1-1 and 2-1 t DM ha"'). The medium-leaved varieties Donna, Menna and Grasslands Huia behaved similarly to the large-leaved varieties. Ranking order in the cutting trial was similar to that in the NL trial.Ground covers after three harvest years Correspondence: Mr G. Swift. Scottish Agricultural College, Crop Systems Department, Bush Estate, Penicuik, Midlothian EH26 OPH. UK.differed significantly only under grazing, when the small-leaved varieties had a 2-3 times greater cover than the larger-leaved varieties. A poor separation of the varieties in the NL persistency trial suggests that defoliation was not sufficiently severe to simulate intensive grazing.These comparisons indicate that the performance of clover varieties under the cutting regimes used should not be extrapolated to continuous sheep grazing.

The herbage production and quality of swards of three grass species, prairie grass {Bromus willdenowii Kunth), reed canary-grass (Phalaris arundinacea L.) and phalaris (Phalaris tuberosa L.) were compared with perennial ryegrass (Lolium perenne L.) and hybrid ryegrass (L. perenne L. x L. muitiflorum Lam.) under 6-cut (experiment 1) and 4-cut (experiment 2) regimes over 3 years at Ayr; annually, 360 kg ha"' fertilizer N were applied. At Edinburgh prairie grass was compared with Italian ryegrass (L. muitiflorum Lam.), timothy (Phleum pratense L.) and cocksfoot (Dactylis glomerata L.) under an annual 4-cut regime for 3 years (experiment 3); fertilizer N application totalled 350 kg ha"' annually.Prairie grass gave the highest annual dry matter (DM) production at Ayr, averaging 11 -991 ha"' in experiment 1 and 15-62 t ha~' in experiment 2. Reed canary-grass was much less productive whilst phalaris did not persist after harvest year 1. On average, prairie grass gave 8-lO<7o more DM than the three ryegrasses in the 6-cut system but its advantage was much less under the 4-cut regime. In experiment 3, the DM production of prairie grass and Italian ryegrass were similar in year 1, but following winter damage prairie grass gave the lowest production in subsequent harvest years.Prairie grass had digestibility (OMD) values Correspondence: Dr J. Frame, 'Ard Choille', 13 St Vincent Crescent, Alloway. Ayr KA7 4QW, UK. i Present address: 3 Ravelston House Loan, Edinburgh, EH4 3LY. UK.lower than the ryegrass but higher than reed canary-grass, timothy and cocksfoot. The water soluble carbohydrate (WSC) concentrations in prairie grass were markedly higher than in timothy and cocksfoot but lower than those in Italian ryegrass. Prairie grass had relatively low P and Mg concentrations. Reed canary-grass had relatively low OMD and Ca, but high N, P, K and Mg contents.It is concluded that prairie grass may have potential in the UK as a special-purpose species for conservation management but mainly in the milder climatic areas. The Phalaris species evaluated had disappointing agronomic potential.

Herbage production and quality of swards of brome grass (Bromus carinatus. Hook and Am) were compared with other commonly sown grasses at two sites in Scotland. At Ayr, the comparison was with perennial ryegrass (Lolium perenne L.), cocksfoot {Dactylis glomerata L.) and timothy {Phleum pratense L.) under 6-cut (experiment 1) and 4-cut (experiment 2) regimes over 3 years with 360 kg ha"' fertilizer N applied annually in each experiment. At Edinburgh, brome grass was compared over 3 years with perennial ryegrass and cocksfoot under a 7-cut system given 3(X)-35O kg N ha"' year"' (experiment 3) and with perennial ryegrass, cocksfoot and Italian ryegrass (Lolium multiflorum Lam.) under a 4-cut system given 250-325 kg N ha"' annually (experiment 4).Over the 3 years, brome grass gave 1-18, 6-19 and 1-3% less dry matter (DM) production than the other grasses in experiments 1, 2 and 3 respectively; in experiment 4, it was 1 % less productive than Italian ryegrass but 1-2% more productive than the other grasses. The organic matter digestibility (OMD) of brome grass was lower than that of perennial ryegrass but higher than timothy at Ayr, similar to perennial and Italian ryegrasses at Edinburgh but markedly superior to cocksfoot at both sites. N concentrations in brome grass were