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.
2015
Forfattere
Vibeke Vandrup Martens Michel Vorenhout Ove Bergersen Paula Utigard Sandvik Jørgen HollesenSammendrag
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Forfattere
Wendy Marie WaalenSammendrag
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Forfattere
Hugh RileySammendrag
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.
Sammendrag
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Sammendrag
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Forfattere
Gunn StrømengSammendrag
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Sammendrag
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Forfattere
Gunn StrømengSammendrag
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Forfattere
Björn RingselleSammendrag
Elymus repens is a perennial grass weed that causes great yield losses in a variety of crops in the southern and northern temperate zones. Primary control methods for E. repens are herbicides or intensive tillage, both of which have a number of negative side-effects, e.g. herbicides can contaminate groundwater, and tillage can cause increased nitrogen leaching. The aim of this thesis was to investigate how to make non- herbicide control of Elymus repens more resource efficient in terms of less energy demanding soil cultivation and reduced nitrogen leaching. Three field experiments were used to test cover crop competition, mowing and different types of optimised tillage techniques and timing, as well as the combination of under-sown cover crops and mowing or row hoeing. The growth, biomass allocation and morphological responses of E. repens to competition were studied in a greenhouse experiment. The effect of competition from under-sown cover crops on E. repens seems to depend greatly on the cover crop biomass achieved. At high biomass levels, the cover crop can be highly suppressive (Paper IV) and reduce nitrogen leaching (Paper III), while at low levels they can still provide benefits such as reduced E. repens shoot biomass and increased subsequent cereal yield (Paper I). However, a low-yielding red clover cover crop increased E. repens rhizome production by 20-30%. Under-sown cover crops were successfully combined with both mowing and row hoeing (Paper I & III), but while repeated mowing reduced E. repens rhizome production by 35% it could not be shown to give a competitive advantage to the cover crops over E. repens (Paper I). However, the low nitrogen leaching and reduced downward transport of nitrogen when mowing or row hoeing was combined with under-sown cover crops make them interesting control methods for future research. Delaying tine cultivation by a few days after harvest did not reduce E. repens control, but a delay by 20 days tended to result in higher E. repens rhizome biomass and shoot densities, compared to performing it within a few days of harvest. Repeated tine cultivation did not improve control of E. repens or increase subsequent cereal yield, compared to a single cultivation directly after harvest. Repeated cultivation during autumn should therefore not be used categorically, but only when there is reason to believe the shoots will pass the compensation point due to the autumn conditions. We conclude that a site specific approach is necessary to achieve resource efficient control of E. repens.
Sammendrag
The objective of this pilot study was to compare resource use in a mountainous summer farming landscape between old and modern dairy cow breeds during a five-day period. The modern breed used a larger part of the landscape than the old breed, most likely due to differences in habitat patterns. The old breed group preferred semi-natural pastures, while the modern breed preferred overgrown semi-natural meadows, intermediate fen, intermediate wooded fen, and grass-rich sub-alpine birch woodland. Both breeds spent most time grazing grasses, but the modern breed showed a higher frequency of grasses and Vaccinium myrtillus in its diet, while the old breed showed a higher frequency of bushes and trees. The pilot study shows some trends supplementing and strengthening earlier results on how modern and traditional cattle breeds are differing in their impact on vegetation based on their use of space and their different diets.