Contrasting perennial ryegrass / white clover mixtures under cutting and grazing

To study white clover persistence, mixtures of perennial ryegrass cultivars with contrasting growth habits, cvs. Condesa, Wendy and Barlet, and white clover cultivars with different leaf sizes, cvs. Alice, Gwenda and Retor, were evaluated under cutting (clay soil) and under grazing (sand and clay soils). Trials were sown in 1991. No fertilizer N was applied. Under cutting, the large-leaved cv. Alice yielded significantly more in 1992 than the small-leaved cv. Gwenda and the medium-leaved cv. Retor. Clover content ranged from 60 to 90 % of the total DM. Companion grass cultivar did not affect yield or botanical composition. The mixtures yielded 10.6 – 14.6 t ha−1 DM (446 – 599 kg ha−1 N) and the grass monocultures, 1.2 – 2.01 ha1 DM (25 – 46 kg ha−1 N). Grazing trials were conducted on mixed swards of the perennial ryegrass cultivars with white clover cv. Gwenda. The plots were continuously stocked with steers, aiming at an average sward height of 7–8 cm. The clover content (DM basis) in April ranged from 31 to 42 % on the sandy soil and on clay soil from 11 to 16%. The ground cover of white clover in April was, on average, 36 % on sand and 11 % on clay; in June it increased to 48 % on sand and 23 % on clay. Mean individual liveweight gain of steers during the grazing season was 710 g d−1 on sand and 470 g d−1 on clay. Mean net production in terms of kVEVI ha−1 was 9871 on sand and 8231 on clay. There was no effect of grass cultivar on liveweight gain or net production.