Ulrich Thumm

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

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]

Fertilizing Potential of Separated Biogas Digestates in Annual and Perennial Biomass Production Systems

Digestates produced by the increasing number of biogas plants require appropriate treatment or recycling. This study investigates the fertilizing potential of separated biogas digestates. These contain valuable nutrients and can be used in agriculture to close the nutrient cycle. Multi-year field experiments were established at two challenging sites in south-west Germany in 2010; results from six years are shown here. The objectives were to determine 1) whether separated digestates can complement or substitute mineral fertilizers and 2) their effect on long-term yield performance in different biomass cropping and fertilization systems. The fertilizing performance was assessed in a split-plot design with four replications using three cropping systems: 1) perennial grassland; 2) intercropping of triticale and clover grass; 3) silage maize. Five N fertilization treatments were applied, each at 150 kg N ha-1: mineral fertilizer (calcium ammonium nitrate) combined solid digestate fraction and mineral fertilizer solid digestate fraction combined liquid digestate fraction and mineral fertilizer liquid digestate fraction. The influences of site, cropping system, year and fertilization treatment were highly significant. The mineral fertilizer and combination ‘liquid digestate fraction + mineral fertilizer’ mostly led to the highest quantitative biomass yields in all cropping systems at both sites. Fertilization with solid digestate fraction produced lowest yields in all fertilized plots, with results very often not significantly different from the untreated control. Maize achieved relatively high yields in years with favorable weather conditions; unfavorable conditions led to low yields. The grassland and intercropping systems were less susceptible to weather conditions, producing a more constant biomass supply irrespective of site, treatment and year. The separated biogas digestates were found to have a comparable effect to mineral fertilizer on biomass yield, but this varied with cropping system. In the intercropping system, complete substitution was possible. The solid fraction is more likely to contribute positively to soil humus in annual systems. In general, the combined application of digestate and mineral fertilizer is highly recommendable to meet crops’ short- and long-term N demand, even on challenging sites. In this study, it allowed a mineral fertilizer input reduction of 66%.

Co-operative grazing Systems (“Allmende”): An alternative concept for the management of endangered open and semi-open landscapes

The article gives an insight into the research project “Co-operative grazing Systems: An alternative concept for the management of endangered open and semi-open landscapes”. Cooperatively grazed pastures in the south-west of Bavaria are analysed with regard to their ecological and economic structures. The organization, hypothesis and methods of the project are discussed. Proceeding from preliminary results, the research area is characterized.

Miscanthus-Complemented Grassland in Europe: Additional Source of Biomass for Bioenergy

Grasslands are estimated to cover over 40 % of the Earth’s land surface. Due to the large areas occupied and environmental effects, grasslands are important for bioenergy and biofuel. In Europe, most grasslands are maintained by regular mowing or grazing. For those on nutrient-poor soils, such maintenance is especially important to avoid species succession and loss of biodiversity. Many European grasslands, particularly semi-natural grasslands growing on nitrogen-poor and stony shallow soils, do not produce high biomass yields, making their maintenance economically unattractive for farmers. However, these poor-soil grasslands usually maintain the highest plant and animal species diversity.