Hopp til hovedinnholdet

Publications

NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.

2017

To document

Abstract

Soil application of organic residues from anaerobic digestion of municipal food waste and/or sewage sludge may introduce considerable amounts of heavy metals into the environment. In a column leaching experiment, mobility and release of Cu, Ni and Zn were investigated in three contrasting soils (sand, silt, loam) fertilized with biogas digestates of different origin. The effect of commercial digestates, based on food waste and sewage sludge, was compared to that of experimental digestates based on animal manure and whey permeate with or without fish ensilage, as well as untreated manure, mineral fertilizer and an untreated control. Manure and digestates were added to the columns as fresh material at equal amounts of available nitrogen. The experiment simulated high-intensity rainfall over a period of 7 days. In general, soil treated with the commercial digestates with higher original metal content showed less environmental impact in terms of Ni, Cu and Zn leaching than that treated with experimental digestates with lower original metal content and less than when animal manure or mineral fertilizer was applied. Although effects of digestate application on metal mobility in soils were seen in conditions of extreme precipitation, the leached concentrations of metals were below limitations published by the WHO but still significantly higher than that measured for control soils.

To document

Abstract

Extensive green roofs have become a frequently used option for stormwater retention across manydifferent climates including cold and wet regions. Despite the extensive documentation of green rooftechnology for stormwater management, the knowledge about their function and potential use in wetand cold regions is deficient. Using historic data on daily temperature and precipitation in a green roofwater balance model coupled with the Oudin model of evapotranspiration (ET), we evaluated the effects ofmaximum green roof storage capacities (Smax) and ET on stormwater retention along climatic gradientsin Northern Europe. Large differences in potential annual stormwater retention were found betweenlocations, driven by differences in temperature and precipitation amounts. Highest retention in abso-lute values was found for the wettest locations, while the warmest and driest locations showed highestretention in percentage of annual precipitation (up to 58% compared to 17% for the lower range). Alllocations showed a considerable retention of stormwater during summer, ranging from 52% to 91%. Stor-age capacities accepting drought conditions once every 3.3–3.9 year were found to be about 25 mm inthe cold and wet locations increasing to 40–50 mm in the warmer and drier locations. Correspondingstorage capacities to prevent wilting of non-succulent vegetation was on average a factor of 1.5 larger(not including Sheffield and Malmö). Annual retention increased both with an increase in plant wateruse (specific crop factors, Kc) and with an increase in Smax, but was found to be more sensitive to changesin Kcthan to changes in Smax. Hence, ET was the limiting factor for green roof retention capacity in thecold and wet locations, but relatively large changes in evapotranspiration would be needed to have animpact on retention. The potential to use vegetation with higher water use to better restore the storagecapacity between storm-events in these regions was however limited by the risk of permanent wilting ofnon-succulent vegetation, even on the wettest locations. A considerable increase in roof storage capacityand substrate thickness would be required to reduce this risk; still the increase in stormwater retentionwould be marginal.

To document

Abstract

Habitat descriptors are cost effective biodiversity indicators demanded by stakeholders and required for regional and global biodiversity monitoring. We mapped 195 farms of different types in twelve case study regions across Europe and tested 18 habitat descriptors for scientific validity, information content and ease of interpretation. We propose a core set consisting of (i) four descriptors to measure structural composition and configuration of farms (Habitat Richness, Habitat Diversity, Patch Size, and Linear Habitats), (ii) three descriptors addressing specific habitat types (Crop Richness, Shrub Habitats, and Tree Habitats) and (iii) one interpreted descriptor (Semi-Natural Habitats). As a set, the descriptors make it possible to evaluate the habitat status of a farm and to track changes occurring due to modified land use and/or management, including agri-environmental measures. The farm habitat maps can provide ground truth information for regional and global biodiversity monitoring.

To document

Abstract

Revegetation of roadsides is an opportunity for grassland restoration, yet these habitats are prone to be colonised by invasive alien plant species (IAS). Therefore, the selection of seed mixtures for revegetation should consider potential competition with IAS present in the soil seed bank or arriving by traffic-related seed rain. We investigated whether the limiting similarity hypothesis, in terms of plant seed-size-output strategy, could be used to design native grassland communities resistant to IAS. In a greenhouse experiment, a small- or a large-seeded IAS was sown into factorial combinations of two native communities with small or large seed-size-output strategies attwo sowing densities. Height and aboveground biomass of the IAS were measured after four and eight weeks, respectively. Small-seeded native communities at high density were highly effective in suppressing the small- and large-seeded IAS, mostly controlled by a density effect. Thus, limiting similarity in seed-size-output strategy only partly explained resistance to IAS, while density-driven suppression was more effective.