Grass Species and Cultivar Effects on Establishment of Grass–White Clover Mixtures

Abstract

Grasses may differ in their compatibility with white clover (Trifolium repens L.) during establishment. We conducted greenhouse and field experiments to evaluate the compatibility of early‐ and late‐maturing cultivars of perennial ryegrass (Lolium perenne L.) and orchardgrass (Dactylis glomerata L.) with ‘Will’ white clover during establishment. Monocultures and binary mixtures of each cultivar with white clover were established from seed in pots in two greenhouse studies. After an initial harvest at 6 wk of growth, plants were harvested every 2 or 4 wk at a 4‐ or 8‐cm height for 8 wk. The same monocultures and mixtures were planted in field plots and harvested twice at 4 or 8 cm after an 11‐wk establishment period. White clover produced more (P < 0.05) stolon + leaf mass and clover proportion of herbage yield was greater when grown with early‐maturing than with late‐maturing grass cultivars in the field and greenhouse. This indicates that early‐maturity grasses were more compatible with white clover. Individual perennial ryegrass plants had about twice as many tillers per plant (P < 0.01) and yielded 24% more (P < 0.01) dry matter than orchardgrass in mixture with clover. Perennial ryegrass–clover mixtures yielded 20% more herbage and had 40% more tillers per unit area than orchardgrass–clover in the field. Clover plants in monoculture were heavier and more complex in structure than plants in mixture in both field and greenhouse. We conclude that maturity of grass cultivars has an effect on white clover establishment and that early‐maturing cultivars of perennial ryegrass or orchardgrass are more compatible with Will white clover during the establishment phase.