Designing high-yielding, high-diversity and low-input temporary grasslands

Summary

Species-rich swards have received increasing interest due to their focus on ecosystem services, animal welfare and product quality. However, in high-yielding swards the proportion of herbs is often limited and there is little knowledge of their management. Seed mixture composition, cutting frequency, fertilization and grazing/cutting strategies were examined over 4 years in 3 experiments to quantify their effects on herbage yield and botanical composition. Inclusion of herbs in the sward gave similar or higher annual yields but swards established with 100% herbs depended on the presence of a driver species. The
effects of management differed between species. Herb content in the sward was significantly related to the proportion of herbs in the seed mixture, whereas botanical composition was related to defoliation frequency. Continuous grazing with heifers reduced the proportion of herbs, relative to cutting, and reduced the competitiveness of ribwort plantain, caraway and lucerne, whereas chicory was unaffected. Fertilization with cattle slurry reduced the proportion of legumes and increased most of the nonleguminous species. Herb proportions changed over the 4 years, with plantain decreasing and caraway increasing. Growing weak competitors together, such as salad burnet and dandelion, with one legume showed possibilities for improving the proportion of these species in the sward. In general, it was possible to maintain diversity in the swards but with changing botanical composition over years. However maintaining weak competitors requires a special planting design.