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.
2014
Authors
J E Munyaneza V G Sengoda Leif Sundheim Richard MeadowAbstract
No abstract has been registered
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Authors
Aytac ErdemirAbstract
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Authors
Aytac ErdemirAbstract
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Authors
Samuli Launiainen Martyn N. Futter David Ellison Nicholas Clarke Leena Finér Lars Högbom Ari Laurén Eva RingAbstract
No abstract has been registered
2013
Authors
Tina AndersenAbstract
Mycorrhiza is an ancient and widespread form of symbiosis that takes place when specialized, soil-living fungi colonize plant roots, where they exchange nutrients like nitrogen (N) and phosphorus (P) in return of carbon sugars. Besides enhanced nutrient uptake, mycorrhizal relationships often provide additional benefits like increased resistance to drought, chilling, salinity and pathogens, to the host. In this context, the golf industry, which is challenged by the need to restrict inputs of fertilizers, pesticides and energy for irrigation and mechanical maintenance, is interested in utilizing these symbiotic associations to improve green quality in a more environmentally friendly and cost-effective way. Little is known about mycorrhizal colonization in turfgrasses, but since greens are believed to be generally poor in mycorrhizal forming fungi compared to natural soil habitats, there is focus on applying commercial inocula to ‘boost’ the extent of colonization in these plants. The ultimate goal is that inoculation will improve green quality through early establishment, enhanced growth and stress tolerance. In addition, the potential in controlling the invasive annual bluegrass (Poa annua) by means of mycorrhizal inoculation is under investigation, because this species have been found to benefit less from these symbiotic interactions than other, frequently used turfgrasses on golf greens. The objective of this thesis was to investigate how green management practices affect mycorrhizal colonization in different turfgrass species. More specifically; I studied how N/P rates, type of growth medium and inoculation with a mycorrhiza product affected arbuscular mycorrhizal colonization in different turfgrass species on sand based golf greens, as well as how the symbiosis affected green quality in interaction with these management practices. The research was conducted on two already established greens at Bioforsk Landvik, Grimstad, that were testing effects of different green management on turf quality, playability and competition against annual bluegrass on Scandinavian golf greens. Root samples were harvested from both fields, and analyzed for percent mycorrhizal colonization before a suggestion of possible fungal genera were made based on observed mycorrhizal structures. Root weights were also recorded. In addition, data analyses and visual data that had been recorded on turf quality through the whole growth season in conjunction with the main projects were obtained for both fields. An initial greenhouse experiment was performed at the Center for Climate Controlled Plant Research at Ås, Akershus, where the same growth media, mycorrhizal inoculum and turfgrass species as in the field trials were tested over a thirteen week period. Collection of clippings and visual data recordings were performed at regular intervals. By the end of the experiment, the roots from each pot were harvested and analyzed in the same manner as with the samples from the field studies. Total above-ground material was also collected from each pot and weighed. Turf quality increased with increasing N availability. At the higher N-levels, the incidence of disease and annual bluegrass competition was limited, while the general impression was better. This was also true for root zones amended with compost instead of peat, the former releasing nutrients more easily. However, in the greenhouse study, plants grown with peat as organic amendment had the best growth, due to excessive N-fertilizing in these pots that was overshadowing the effect of compost amendment. There were no significant effects of phosphorus on either turf quality or mycorrhial colonization. Mycorrhizal colonization was high in all turfgrass species, except for the greenhouse experiment, where the inoculum tested showed no significant effects. The bentgrasses seemed to be the most mycorrhizal species, but the difference in colonization between red fescue and annual bluegrass was somewhat unclear. Moreover, these results were not significant. There were no significant effects of N/P rates on mycorrhizal colonization either, but a tendency pointed towards increasing colonization with decreasing N amounts. Furthermore, colonization rates increased when compost was incorporated into the root zone instead of peat. There were no significant effects of inoculation in the field studies, although a small tendency pointed towards a reduction in annual bluegrass, as well as increased P removal from the soil, in inoculated plots. The results showed several interactions between species and N-level, and between species and growth medium. This underlines that processes related to plant growth and quality as well as symbiosis development is largely controlled by N availability, but also that growth responses to this element are related to individual species growth potentials. Mycorrhizal growth responses was probably neutral or could not be detected in the different species because the high nutrient availability in the greens was overshadowing any mycorrhizal effect, and this further indicates that direct uptake of available N is the primary cause of increased plant fitness in greens. The lack of significances when testing the mycorrhiza inoculum illustrates that successful incorporation of such commercial products into the field may be a challenge. However, use of compost in the root zone of the youngest green seemed to increase the colonization rates, and if simple measures like this can accelerate the establishment of neutral, mycorrhizal fungal populations in the future, inoculating greens during construction may not be necessary.
Abstract
Nitrogen (N) efficiency on farm gate is studied for the year 2010 on ten Norwegian, organic dairy farms and ten conventional as references. Preliminary results are presented here, and the method is discussed. N-efficiency is calculated as Net N-Export (kg) / Net N-Import (kg). Nitrogen from biological N-fixation had a large impact on calculated N-efficiency. Because of large annual variations and uncertain estimates of amount of N from biological N-fixation caused by uncertainties in roughage yields, clover content and the amount of nitrogen fixed per kg clover harvested, the numeric values of estimated N-efficiency should not be taken as exact values. N-efficiency is estimated with and without biological N fixation. There are large variations in farm size, use of concentrates and milk yield per cow within the group of organic farms. However, the variation is even larger within the conventional farms. On average, the estimated N-efficiency was higher on the organic than on the conventional farms. However, there are large variations in estimated N-efficiency within the organic as well as the conventional group. This gives us the possibility to identify on which farms actions should be taken to improve N-efficiency.
Authors
Ingeborg Callesen Lars Ola Nilsson Inger Kappel Schmidt Lars Vesterdal Per Ambus Jesper Riis Christiansen Peter Högberg Per GundersenAbstract
No abstract has been registered
Authors
J. Leppälammi-Kujansuu I. Ostonen M. Strömgren Lars Ola Nilsson D.B. Kleja S.P. Sah H.-S. HelmisaariAbstract
No abstract has been registered
Authors
M. Butac V. Bozhkova A. Zhivondov N. Milosevic E. Bellini V. Nencetti J. Blazek E. Balsemin B. Lafarque E. Kaufmane I. Gravite M. Vasiljeva M. Pintea A. Juraveli T. Webster I. Hjalmarsson V. Trajkovski Stein Harald HjeltnesAbstract
No abstract has been registered