Bodil E. Frankow-Lindberg

Ecosystem function enhanced by combining four functional types of plant species in intensively managed grassland mixtures: a 3‐year continental‐scale field experiment

1.A coordinated continental-scale field experiment across 31 sites was used to compare the biomass yield of monocultures and four species mixtures associated with intensively managed agricultural grassland systems. To increase complementarity in resource use, each of the four species in the experimental design represented a distinct functional type derived from two levels of each of two functional traits, nitrogen acquisition (N2-fixing legume or nonfixing grass) crossed with temporal development (fast-establishing or temporally persistent). Relative abundances of the four functional types in mixtures were systematically varied at sowing to vary the evenness of the same four species in mixture communities at each site and sown at two levels of seed density. 2.Across multiple years, the total yield (including weed biomass) of the mixtures exceeded that of the average monoculture in >97% of comparisons. It also exceeded that of the best monoculture (transgressive overyielding) in about 60% of sites, with a mean yield ratio of mixture to best-performing monoculture of 1·07 across all sites. Analyses based on yield of sown species only (excluding weed biomass) demonstrated considerably greater transgressive overyielding (significant at about 70% of sites, ratio of mixture to best-performing monoculture = 1·18). 3.Mixtures maintained a resistance to weed invasion over at least 3 years. In mixtures, median values indicate

Biodiversity effects on yield and unsown species invasion in a temperate forage ecosystem

BACKGROUND AND AIMS Current agricultural practices are based on growing monocultures or binary mixtures over large areas, with a resultant impoverishing effect on biodiversity at several trophic levels. The effects of increasing the biodiversity of a sward mixture on dry matter yield and unsown species invasion were studied. METHODS A field experiment involving four grassland species [two grasses--perennial ryegrass (Lolium perenne) and cocksfoot (Dactylis glomerata)--and two legumes--red clover (Trifolium pratense) and white clover (Trifolium repens)], grown in monocultures and mixtures in accordance with a simplex design, was carried out. The legumes were included either as single varieties or as one of two broad genetic-base composites. The experiment was harvested three times a year over three years; dry matter yield and yield of unsown species were determined at each harvest. Yields of individual species and interactions between all species present were estimated through a statistical modelling approach. KEY RESULTS Species diversity produced a strong positive yield effect that resulted in transgressive over-yielding in the second and third years. Using broad genetic-base composites of the legumes had a small impact on yield and species interactions. Invasion by unsown species was strongly reduced by species diversity, but species identity was also important. Cocksfoot and white clover (with the exception of one broad genetic-base composite) reduced invasion, while red clover was the most invaded species. CONCLUSIONS The results show that it is possible to increase, and stabilize, the yield of a grassland crop and reduce invasion by unsown species by increasing its species diversity.

The Agrodiversity Experiment: three years of data from a multisite study in intensively managed grasslands

Kirwan, L., Connolly, J., Brophy, C., Baadshaug, O. H., Belanger, G., Black, A., Carnus, T., Collins, R. P., Cop, J., Delgado, I., De Vliegher, A., Elgersma, A., Frankow-Lindberg, B. E., Golinski, P., Grieu, P., Gustavsson, A., Helgadottir, A., Hoglind, M., Huguenin-elie, O., Jorgensen, M., Kadziuliene, Z., Lunnan, T., Luscher, A., Kurki, P., Porqueddu, C., Sebastia, M. T., Thumm, U., Walmsley, D. & Finn, J. A. (2014). The Agrodiversity Experiment: three years of data from a multisite study in intensively managed grasslands. Ecology, 95 (9), [2680]

The Agrodiversity Experiment: three years of data from a multisite study in intensively managed grasslands Ecological Archives

Kirwan, L., Connolly, J., Brophy, C., Baadshaug, O. H., Belanger, G., Black, A., Carnus, T., Collins, R. P., Cop, J., Delgado, I., De Vliegher, A., Elgersma, A., Frankow-Lindberg, B. E., Golinski, P., Grieu, P., Gustavsson, A., Helgadottir, A., Hoglind, M., Huguenin-elie, O., Jorgensen, M., Kadziuliene, Z., Lunnan, T., Luscher, A., Kurki, P., Porqueddu, C., Sebastia, M. T., Thumm, U., Walmsley, D. & Finn, J. A. (2014). The Agrodiversity Experiment: three years of data from a multisite study in intensively managed grasslands. Ecology, 95 (9), [2680]