Mixture of Alfalfa, Orchardgrass, and Tall Fescue Produces Greater Biomass Yield in Southwest China

Abstract

The current study investigated the influence of mixture composition on the biomass yield and early establishment of legume–grass mixtures. The legume species alfalfa (Medicago sativa L. (A)), white clover (Trifolium repens L. (WC)), and red clover (Trifolium pratense L. (RC)) and grass species orchardgrass (Dactylis glomerata L. (O)), tall fescue (Festuca arundinacea Schreb. (TF)), and perennial ryegrass (Lolium perenne L. (PR)) were grown in monocultures and in different legume–grass mixtures. Legume–grass mixtures (M1: WC + O + TF; M2: A + O + TF; M3: A + WC + O + TF; M4: RC + WC + O + TF; M5: A + WC + O + TF + PR; M6: RC + WC + O + TF + PR; and M7: A + RC + WC + O + TF + PR) were sown in a legume–grass seeding ratio of 3:7. The results showed that M2 had the greatest two-year average biomass yield (12.92 t ha−1), which was significantly (p < 0.05), 4.7%, 5.4%, 15.8%, and 29.1% greater than that of WC monoculture, M7, M4, and M1, respectively. The grass biomass yield proportions of all mixtures significantly decreased, while legume biomass yield proportions significantly increased in the second year compared to the first year of establishment. The land-equivalent ratio values of M2 and M4 were greater than 1 in each cutting period. The competition rate of grasses gradually decreased with prolonged establishment time. Overall, the biomass yield, legume and grass biomass yield proportions, land equivalent ratio, and competition rate data highlighted that M2 is the best choice to achieve greater productivity and early establishment in southwest China.