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Publikasjoner

NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.

2016

Sammendrag

Mineral NPK fertilizer and manure have been compared since 1922 in a ley–arable rotation. During 1982–2003, cattle manure at 20–60 Mg ha−1 year−1 yielded 10–20 % less than mineral fertilizer at 100 kg N:25 kg P:120 kg K ha−1 year−1. The higher manure rates gave large nutrient surpluses. Both manure and mineral fertilizer had increased soil organic carbon (SOC), by 11.3 and 3.4 Mg ha−1 in 1996. In order to study possible residual effects, no manure was applied in 2004–2007 and mineral fertilizer was withheld from some NPK plots. Effects on yield and nutrient uptake were evaluated in relation to plots with no nutrient supply since 1922 and plots still receiving 100 kg N, 25 kg P and 120 kg K ha−1 annually. No residual response of mineral fertilizer was found, but previous manure use gave large effects. The latter yields remained around 85 % of those obtained with mineral fertilizer. Previous use of both mineral fertilizer and manure still increased available soil nutrients and pH in 2007. Differences between treatments in SOC had by then declined slightly, to 9.7 and 2.8 Mg ha−1 for manure and mineral fertilizer respectively, relative to the unfertilized control. Manure and fertilizer applications were resumed in 2008, except at the highest previous manure rate, where mean residual responses up to 2014, relative to the unfertilized control, amounted to 55 % higher yield and increases in nutrient uptake of 47 kg N, 8 kg P and 53 kg K ha−1.

Til dokument

Sammendrag

The study examines the economics of different calf rearing systems and considers effects of suckling and milk feeding on production, health and welfare of dairy cows and growth, milk and feed use, health and welfare of calves. The economics of (i) no suckling, (ii) suckling for 3 days, (iii) suckling for 7 weeks, all assuming milk or milk replacer fed until weaning at 13 weeks, was compared with (iv) suckling for 13 weeks and no milk feeding. A linear programming (LP) model, maximizing profit on a dual purpose dairy-beef farm in lowland eastern Norway, was used for the comparison. Details on calf rearing methods, labor, weaning age, intake of milk, and solid feed were gathered for a sample of organic farms and grouped according to the length of the suckling period. The data were coupled with the National Dairy Herd Recording System (NDHRS) using cross-sectional data for the years 2008–2013. The results of the model study showed that suck- ling up to at least 7 weeks and longer than on most farms in the survey, had a positive influence on the farm economics. This was due to the positive influence on calf growth and health as well as lowered costs. Consequently, dual purpose dairy-beef farmers should be careful to sacrifice calf suckling and restrict calf milk feeding. Long suckling until weaning at 13 weeks was, however, unprofitable.

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Sammendrag

BACKGROUND Plants grown at different latitudes experience differences in light spectral composition. Broccoli (Brassica oleracea L. var italica) plants were grown in climate-controlled chambers under supplemental wavelengths (red, far-red, red + far-red or blue) from light-emitting diodes (LEDs). The light treatments were combined with two cold climate temperatures (12 and 15 °C) during broccoli head formation to investigate the effects on morphology and content of health- and sensory-related compounds: glucosinolates, flavonols, ascorbic acid and soluble sugars. RESULTS Supplemental far-red and red + far-red light led to elongated plants and the lowest total glucosinolate content in broccoli florets. The content of quercetin was highest with supplemental red light. Vitamin C was not significantly affected by the light treatments, but 12 °C gave a higher content than 15 °C. CONCLUSION The effects of supplemental red and far-red light suggest an involvement of phytochromes in the regulation of glucosinolates and flavonols. A shift in red:far-red ratio could cause changes in their content besides altering the morphology. The sugar and vitamin C content appears to be unaffected by these light conditions. Supplemental blue light had little effect on plant morphology and content of the health- and sensory related compounds.

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Sammendrag

Spatially explicit knowledge of recent and past soil organic carbon (SOC) stocks in forests will improve our understanding of the effect of human- and non-human-induced changes on forest C fluxes. For SOC accounting, a minimum detectable difference must be defined in order to adequately determine temporal changes and spatial differences in SOC. This requires sufficiently detailed data to predict SOC stocks at appropriate scales within the required accuracy so that only significant changes are accounted for. When designing sampling campaigns, taking into account factors influencing SOC spatial and temporal distribution (such as soil type, topography, climate and vegetation) are needed to optimise sampling depths and numbers of samples, thereby ensuring that samples accurately reflect the distribution of SOC at a site. Furthermore, the appropriate scales related to the research question need to be defined: profile, plot, forests, catchment, national or wider. Scaling up SOC stocks from point sample to landscape unit is challenging, and thus requires reliable baseline data. Knowledge of the associated uncertainties related to SOC measures at each particular scale and how to reduce them is crucial for assessing SOC stocks with the highest possible accuracy at each scale. This review identifies where potential sources of errors and uncertainties related to forest SOC stock estimation occur at five different scales—sample, profile, plot, landscape/regional and European. Recommendations are also provided on how to reduce forest SOC uncertainties and increase efficiency of SOC assessment at each scale.