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
Abstract
Mineable rock phosphate is a limited resource. Replacing mineral phosphorus (P) fertiliser with P-rich secondary resources is one way to manage P more efficiently. The Norwegian potential to replace mineral P fertiliser with total P in secondary resources was analysed here using substance flow analysis. The results obtained were integrated with data on P plant-availability in secondary resources and showed that, theoretically, plant-available P in manure alone could fulfil the Norwegian demand for P fertiliser. However, P in manure is inefficiently utilised due to the geographical segregation of animal husbandry and arable farming, which contributes to considerable P over-application to agricultural soil. In Norway, agriculture and aquaculture drive P consumption and losses at similar levels, and the amount of P in fish excrement and feed losses from off-shore aquaculture pens (fish sludge) is of the same order of magnitude as P in manure. Fish sludge is currently not collected or utilised, but lost to coastal marine waters. All other secondary resources represent relatively small amounts of P, but may still be important regionally. Political incentives are thus needed in current regulations to efficiently close P cycles. To achieve P recycling in practice, it is essential to know the relative agronomic efficiency (RAE) of secondary P products compared with mineral fertiliser. Nine secondary P products were analysed here: Two biomass ashes, meat bone meal, fish sludge, catering waste, two food waste-based digestate products, dairy manure and chicken manure. The RAE of these secondary products studied in a bioassay with ryegrass (Lolium multiflorum) varied widely, partly depending on soil pH. Fertilisation effects were mainly attributable to the solubility of the inorganic P species contained in the secondary products. Combining sequential chemical fractionation and non-destructive speciation methods revealed that P was mainly present as calcium phosphates of differing solubility. Further analysis showed that microbial and physicochemical soil processes induced by the secondary P products studied were of little overall importance for total P uptake in barley (Hordeum vulgare). Based on the results obtained, two chemical extraction methods for predicting the RAE of secondary products with unknown fertilisation effects are suggested: At soil pH <6.5, RAE should be predicted by the fraction of inorganic P in the secondary product (% of total P) that is extractable in H2O. At soil pH >6.5, RAE should be predicted by the fraction of inorganic P (% of total P) that is extractable in 0.5 M NaHCO3 (Olsen P).
Abstract
No abstract has been registered
Authors
Pia Heltoft Thomsen Jennie L. Brierley Alison K. Lees Louise Sullivan James Lynott Arne HermansenAbstract
A glasshouse experiment was carried out with the aim of quantifying the relative contribution of seed- and soil-borne inoculum of three Fusarium spp. (F. coeruleum, F. sambucinum and F. avenaceum) in causing dry rot in two potato cultivars, Asterix and Saturna. Different concentrations of inoculum; control (water only), low (102 conidia ml−1) and high (105 conidia ml−1) were used to inoculate seed and infest soil and disease severity on progeny tubers was subsequently assessed following an 8-week post-harvest storage period. Overall, F. sambucinum caused significantly (P < 0.05) larger rots than F. avenaceum, with the severity of rots caused by F. coeruleum being intermediate, and disease severity was greater in cv. Asterix than cv. Saturna (P < 0.01). None of the seed inoculation treatments resulted in dry rot development on progeny tubers. In contrast, soil infested with Fusarium species resulted in significantly more severe tuber rots on progeny tubers compared with controls (P < 0.01). Soil infested with F. sambucinum (low and high levels) resulted in significantly more severe rots than control treatments (P < 0.001), whilst only high levels of F. avenaceum soil inoculum increased the severity of tuber rots compared with control treatments (P < 0.05). Increased disease severity observed as a result of the addition of inoculum of F. coeruleum to soil was not significant.
Abstract
No abstract has been registered
Abstract
The report is based on information Norway provided in an electronic questionnaire that was prepared by FAO to collect national data as a contribution to The State of the World’s Biodiversity for Food and Agriculture. The report presents information on the status and trends of biodiversity for food and agriculture, including animals, plants and micro-organisms with a direct or indirect role in agriculture, forestry and/or fisheries. A lot of data on these issues is available in Norway; however it is mostly spread across different monitoring systems and fragmented. The report draws attention to the use and conservation of biodiversity for food and agriculture and to the function(s) of and interactions between its components in production systems. The report focuses more on associated biodiversity, ecosystem services and wild foods than on plant, animal and forest genetic resources as these are presented in other reports. Even if the awareness on the importance of associated biodiversity to food production and food
Abstract
No abstract has been registered
Abstract
No abstract has been registered
Abstract
In Europe, common ash (Fraxinus excelsior) is being decimated because of the invasive fungus Hymenoscyphus fraxineus. In its native range in Asia this ascomycete is considered a harmless leaf associate of F. mandshurica and F. chinensis subsp. rhynchophylla. Field observations from Europe suggest that there is speciesspecific variation in disease susceptibility among European and North American Fraxinus species, but a wider comparison at the genus level has been missing so far. We assessed disease symptoms and pathogen apothecium development in 17 Fraxinus species from Asia, Europe and North America exposed to high infection pressure in a Danish arboretum. We also tested their susceptibility to pathogen infection through controlled stem and leaf inoculations and subsequently assessed the level of pathogen DNA by a qPCR assay. The results suggested the presence of a phylogenetic signal in disease susceptibility where closely related Asian, European and North American species in section Fraxinus had relatively high levels of H. fraxineus DNA in the leaves and supported high production of apothecia. Leaves from some North American species also contained relatively high levels of H. fraxineus DNA, supported moderate production of apothecia and developed lesions—stating the need to avoid introduction of H. fraxineus to North America.
Authors
Svein SolbergAbstract
No abstract has been registered
Authors
Frank Maas M. Mekjell MelandAbstract
The response of three-year-old 'Summerred' trees to crop load regulation by the chemical thinning agent Brevis® was tested in comparison with different levels of hand thinning. Brevis® was applied once or twice at a dosage of 1.1 and 2.2 kg ha-1 when fruitlets were approximately 15 and 19 mm in diameter at the time of the first and second application, respectively. All Brevis® applications significantly reduced the number of fruits tree-1. Both the single application of 2.2 kg ha-1 and the two-fold application of 1.1 kg ha-1 thinned the tree to the target crop load level of 30 apples tree-1. The degree of thinning by the single application of 1.1 kg ha-1 Brevis® did not significantly increase fruit weight and resulted in a very strong inhibition of return bloom similar to that observed in the untreated controls and trees hand thinned to 60 fruits tree-1. Return bloom was positively related to the level of thinning obtained. At the target fruit load of about 30 apples tree-1, return bloom was around 40% of the bloom in the year of the thinning trial. A further thinning to circa 15 fruits tree-1 increased return bloom to approximately 60%. In conclusion, 'Summerred' trees planted as two-year-old feathered trees should not bear more than 20 to 25 fruits tree-1 in their 3rd leaf in a northern climate to avoid the onset of biennial bearing and to ensure regular annual yields. Only then sufficient numbers of flower buds will develop to have the chance to obtain a good crop in the next year.