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.
2016
Authors
Sarah Calvache Gil Tatsiana Espevig Tina E. Andersen Erik J. Joner Agnar Kvalbein Trond Olav Pettersen Trygve S. AamlidAbstract
Red fescue (RF, Festuca rubra L.) is used on golf putting greens in the Nordic region due to its high disease resistance and low requirements for nitrogen (N) and water, but low density and growth rate makes RF susceptible to annual bluegrass (AB, Poa annua L.) invasion. Putting greens seeded with RF + bentgrass (Agrostis sp.) may be more competitive with AB but also have different playing characteristics. Our objective was to compare RF, RF + colonial bentgrass (CB, Agrostis capillaris L.), and RF + velvet bentgrass (VB, Agrostis canina L.) putting greens at two mowing heights (4.0 or 5.5 mm), three N rates (5, 10, or 15 g N m−2 yr−1), and three phosphorus (P)–arbuscular mycorrhizal fungi treatments (0 and 1.8 g P m−2yr−1 without inoculation and 0 g P m−2yr−1 with inoculation). The four-factorial experiment was conducted in 2011 and 2012 at Landvik, Norway. Red fescue provided lower visual quality and density and less competition against AB than RF + bentgrass combinations. Increasing the N rate from 5 to 15 g N m−2yr−1 increased the proportion of bentgrass tillers from 53 to 64% in RF + CB and from 86 to 92% in RF + VB. Surface hardness increased in the order RF + VB < RF + CB < RF turfs. Ballroll distance decreased with increasing N rate and was longer with RF and RF + VB than with RF + CB. The main effects of N and mowing height on AB invasion were not significant, but lower mowing increased AB competition in RF. Mycorrhiza colonization of roots was not significantly affected by any practice, and neither P nor arbuscular mycorrhizal fungi influenced the competition against AB.
Authors
Yanliang Wang Tore Krogstad Jihong Liu Clarke Moritz Hallama Anne Falk Øgaard Susanne Eich-Greatorex Ellen Kandeler Nicholas ClarkeAbstract
Many arable lands have accumulated large reserves of residual phosphorus (P) and a relatively large proportion of soil P is less available for uptake by plants. Root released organic anions are widely documented as a key physiological strategy to enhance P availability, while limited information has been generated on the contribution of rhizosphere organic anions to P utilization by crops grown in agricultural soils that are low in available P and high in extractable Ca, Al, and Fe. We studied the role of rhizosphere organic anions in P uptake from residual P in four common crops Triticum aestivum, Avena sativa, Solanum tuberosum, and Brassica napus in low- and high-P availability agricultural soils from long-term fertilization field trials in a mini-rhizotron experiment with four replications. Malate was generally the dominant organic anion. More rhizosphere citrate was detected in low P soils than in high P soil. B. napus showed 74–103% increase of malate in low P loam, compared with clay loam. A. sativa had the greatest rhizosphere citrate concentration in all soils (5.3–15.2 μmol g−1 root DW). A. sativa also showed the highest level of root colonization by arbuscular mycorrhizal fungi (AMF; 36 and 40%), the greatest root mass ratio (0.51 and 0.66) in the low-P clay loam and loam respectively, and the greatest total P uptake (5.92 mg P/mini-rhizotron) in the low-P loam. B. napus had 15–44% more rhizosphere acid phosphatase (APase) activity, ~0.1–0.4 units lower rhizosphere pH than other species, the greatest increase in rhizosphere water-soluble P in the low-P soils, and the greatest total P uptake in the low-P clay loam. Shoot P content was mainly explained by rhizosphere APase activity, water-soluble P and pH within low P soils across species. Within species, P uptake was mainly linked to rhizosphere water soluble P, APase, and pH in low P soils. The effects of rhizosphere organic anions varied among species and they appeared to play minor roles in improving P availability and uptake.
2015
Abstract
No abstract has been registered
Abstract
Remediation of soil and groundwater has been attempted using various iron based nanoparticles during more than a decade, but the technology has not been adopted as widely as expected. This is partly due to ongoing work on optimization of the nanoparticles used, as well as their coatings, injection parameters and correct choice of particles according to the pollutants to be treated. Another aspect that has hampered large scale adoption or even testing is the lack of knowledge on possible negative effects of what is perceived a large scale spreading of reactive nanoparticles into the environment. This may potentially cause harm to humans and the environment, including organisms living in soil and neighboring streams, rivers and lakes. Two years ago, the EU project NanoRem (Taking Nanotechnological Remediation Processes from Lab Scale to End User Applications for the Restoration of a Clean Environment) started a considerable effort in valorizing nanoremediation, and as part of this testing the potential toxicity of particles used and developed during the project. After two years, seven different types of nanoparticles have been tested with a range of standardized and non-standardized tests adapted to nanotoxicological assessments, and results show that most particles are non-toxic at environmentally relevant concentrations (<100 mg/kg or mg/L). In some cases, however, iron nanoparticles have shown toxicity at far lower concentrations, and these effects have not been caused by competition for electron acceptors, as often observed when highly reductive chemicals are tested for biological effects. An overview of the tests used and results obtained will be presented. Also, our strategy for field testing and early results from polluted fields injected with different nanoparticles will be discussed to make some preliminary conclusions on the overall benefit of this technology in terms of environmental protection and risks.
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Authors
Linn SolliAbstract
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No abstract has been registered