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.
2019
Sammendrag
We examine the origins, implications, and consequences of yield-based N fertilizer management. Yield-based algorithms have dominated N fertilizer management of corn (Zea mays) in the United States for almost 50 yr, and similar algorithms have been used all over the world to make fertilizer recommendations for other crops. Beginning in the mid-1990s, empirical research started to show that yield-based rules-of-thumb in general are not a useful guide to fertilizer management. Yet yield-based methods continue to be widely used, and are part of the principal algorithms of nearly all current “decision tool” software being sold to farmers for N management. We present details of the theoretical and empirical origins of yield-based management algorithms, which were introduced by George Stanford (1966, 1973) as a way to make N fertilizer management less reliant on data. We show that Stanford’s derivation of his “1.2 Rule” was based on very little data, questionable data omissions, and negligible and faulty statistical analysis. We argue that, nonetheless, researchers, outreach personnel, and private-sector crop management consultants were obliged to give some kind of N management guidance to farmers. Since data generation is costly, it is understandable that a broad, “ball park” rule-of-thumb was developed, loosely based on agronomic principles. We conclude by suggesting that technology changes now allow for exciting new possibilities in data-intensive fertilizer management research, which may lead to more efficient N management possibilities in the near future.
Forfattere
Francisco Javier Ancin Murguzur Gregory Taff Corine Davids Hans Tømmervik Jørgen A.B. Mølmann Marit JørgensenSammendrag
Ruminant fodder production in agricultural lands in latitudes above the Arctic Circle is constrained by short and hectic growing seasons with a 24-hour photoperiod and low growth temperatures. The use of remote sensing to measure crop production at high latitudes is hindered by intrinsic challenges, such as a low sun elevation angle and a coastal climate with high humidity, which influences the spectral signatures of the sampled vegetation. We used a portable spectrometer (ASD FieldSpec 3) to assess spectra of grass crops and found that when applying multivariate models to the hyperspectral datasets, results show significant predictability of yields (R2 > 0.55, root mean squared error (RMSE) < 180), even when captured under sub-optimal conditions. These results are consistent both in the full spectral range of the spectrometer (350–2500 nm) and in the 350–900 nm spectral range, which is a region more robust against air moisture. Sentinel-2A simulations resulted in moderately robust models that could be used in qualitative assessments of field productivity. In addition, simulation of the upcoming hyperspectral EnMap satellite bands showed its potential applicability to measure yields in northern latitudes both in the full spectral range of the satellite (420–2450 nm) with similar performance as the Sentinel-2A satellite and in the 420–900 nm range with a comparable reliability to the portable spectrometer. The combination of EnMap and Sentinel-2A to detect fields with low productivity and portable spectrometers to identify the fields or specific regions of fields with the lowest production can help optimize the management of fodder production in high latitudes.
Sammendrag
The predicted and ongoing climate warming is expected to affect many aspects of plant development. We analysed data from a 31-year series of observations (1985–2016) on spring phenology and flowering and fruiting performance of three plum cultivars in an experimental orchard at Ås in southeast Norway (59° 40′N; 10° 50′E). Regression analyses revealed a trend of increasing March and April temperature during the study period that was highly significantly (P < 0.001) negatively correlated with the date of full bloom (FB). On average for all cultivars, blooming was advanced by 10 days over the study period. August and September temperature, which also increased significantly during the study period, was closely positively correlated with the amount of flowering in the subsequent spring and also interacted with early spring temperature in advancing blooming time. Investigation of the time of floral initiation in two of the studied plum cultivars revealed that the transition to reproductive development took place in early to mid-August. This finding strongly suggests that the close positive correlation between August-September temperature and the amount of flowering in plum observed in this and other studies, is causally linked to a specific physiological effect of elevated temperature on the flower bud formation process. Increasing March and April temperatures during the last 30 years has advanced blooming and spring phenology in plum and the resulting extension of the growing season has led to increasing fruit size at harvest. We conclude that so far, the ongoing climate warming appears to have been positive for plum production in the cool Nordic environment. However, an increasing risk of frost associated with earlier blooming will represent a potential negative effect of continued warming.
Sammendrag
Due to the potential for land-use–land-cover change (LULCC) to alter surface albedo, there is need within the LULCC science community for simple and transparent tools for predicting radiative forcings (ΔF) from surface albedo changes (Δαs). To that end, the radiative kernel technique – developed by the climate modeling community to diagnose internal feedbacks within general circulation models (GCMs) – has been adopted by the LULCC science community as a tool to perform offline ΔF calculations for Δαs. However, the codes and data behind the GCM kernels are not readily transparent, and the climatologies of the atmospheric state variables used to derive them vary widely both in time period and duration. Observation-based kernels offer an attractive alternative to GCM-based kernels and could be updated annually at relatively low costs. Here, we present a radiative kernel for surface albedo change founded on a novel, simplified parameterization of shortwave radiative transfer driven with inputs from the Clouds and the Earth's Radiant Energy System (CERES) Energy Balance and Filled (EBAF) products. When constructed on a 16-year climatology (2001–2016), we find that the CERES-based albedo change kernel – or CACK – agrees remarkably well with the mean kernel of four GCMs (rRMSE = 14 %). When the novel parameterization underlying CACK is applied to emulate two of the GCM kernels using their own boundary fluxes as input, we find even greater agreement (mean rRMSE = 7.4 %), suggesting that this simple and transparent parameterization represents a credible candidate for a satellite-based alternative to GCM kernels. We document and compute the various sources of uncertainty underlying CACK and include them as part of a more extensive dataset (CACK v1.0) while providing examples showcasing its application.
Forfattere
Roger HoltenSammendrag
Det er ikke registrert sammendrag
Sammendrag
Field and laboratory studies show increased leaching of pesticides through macropores in frozen soil. Fast macropore flow has been shown to reduce the influence of pesticide properties on leaching, but data on these processes are scarce. The objective of this study was to investigate the effect of soil freezing and thawing on transport of pesticides with a range of soil sorption coefficients (Kf). To do this we conducted a soil column study to quantify the transport of bromide and five pesticides (2-methyl-4-chlorophenoxyacetic acid, clomazone, boscalid, propiconazole, and diflufenican). Intact topsoil and subsoil columns from two agricultural soils (silt and loam) in southeastern Norway were used in this experiment, and pesticides were applied to the soil surface in all columns. Half the columns were then frozen (−3°C), and the other half were left unfrozen (4°C). Columns were subjected to repeated irrigation events where 25 mm of rainwater was applied during 5 h at each event. Irrigations were followed by 14-d periods of freezing or refrigeration. Percolate was collected and analyzed for pesticides and bromide. Pesticide leaching was up to five orders of magnitude larger from frozen than unfrozen columns. Early breakthrough (<<1 pore volume) of high concentrations was observed for pesticides in frozen columns, indicating that leaching was dominated by preferential flow. The rank order in pesticide leaching observed in this study corresponded to the rank order of mean Kf values for the pesticides, and the results suggest that sorption plays a role in determining leaching losses even in frozen soil.
Forfattere
Ivan Paponov Tatyana Friz Vadym Budnyk William Teale Florian Wüst Martina Paponov Salim Al-Babili Klaus PalmeSammendrag
The vesicle trafficking inhibitor Brefeldin A (BFA) changes the localization of plasma membrane localized PINs, proteins that function as polar auxin efflux carriers, by inducing their accumulation within cells. Pretreatment with the synthetic auxin 1-NAA reduces this BFA-induced PIN internalization, suggesting that auxinic compounds inhibit the endocytosis of PIN proteins. However, the most important natural auxin, IAA, did not substantially inhibit PIN internalization unless a supplementary antioxidant, butylated hydroxytoluene (BHT), was also included in the incubation medium. We asked whether the relatively small inhibition caused by IAA alone could be explained by its instability in the incubation solution or whether IAA might interact with BHT to inhibit endocytosis. Analysis of the IAA concentration in the incubation solution and of DR5 reporter activity in the roots showed that IAA is both stable and active in the medium. Therefore, IAA degradation was not able to explain the inability of IAA to inhibit endocytosis. Furthermore, when applied in the absence of auxin, BHT caused a strong increase in the rate of PIN1 internalization and a weaker increase in the rate of PIN2 internalization. These increases were unaffected by the simultaneous application of IAA, further indicating that endocytosis is not inhibited by the natural auxin IAA under physiologically relevant conditions. Endocytosis was inhibited at the same rate with 2-NAA, an inactive auxin analog, as was observed with 1-NAA and more strongly than with natural auxins, supporting the idea that this inhibition is not auxin specific.
Forfattere
Magnus Löf Palle Madsen Marek Metslaid Johanna Witzell Douglass F. JacobsSammendrag
Conventions and policies for biodiversity conservation and climate change mitigation state the need for increased protection, restoration and climate change adaptation of forests. Much degraded land may be targeted for large-scale forest restoration, yet challenges include costs, a shortage of regeneration material and the need for restored forests to serve as a resource for communities. To ensure ecosystem function for the future, forest restoration programs must: (1) learn from the past; (2) integrate ecological knowledge; (3) advance regeneration techniques and systems; (4) overcome biotic and abiotic disturbances and (5) adapt for future forest landscapes. Historical forest conditions, while site-specific, may help to identify the processes that leave long-term legacies in current forests and to understand tree migration biology/population dynamics and their relationship with climate change. Ecological theory around plant–plant interactions has shown the importance of negative (competition) and positive (facilitation) interactions for restoration, which will become more relevant with increasing drought due to climate change. Selective animal browsing influences plant–plant interactions and challenges restoration efforts to establish species-rich forests; an integrated approach is needed to simultaneously manage ungulate populations, landscape carrying capacity and browse-tolerant regeneration. A deeper understanding of limiting factors that affect plant establishment will facilitate nursery and site preparation systems to overcome inherent restoration challenges. Severe anthropogenic disturbances connected to global change have created unprecedented pressure on forests, necessitating novel ecological engineering, genetic conservation of tree species and landscape-level approaches that focus on creating functional ecosystems in a cost-effective manner.
Forfattere
Sofie Hellsten Tommy Dalgaard Katri Rankinen Kjetil Tørseth Lars Bakken Marianne Bechmann Airi Kulmala Filip Moldan Stina Olofsson Kristoffer Piil Kajsa Pira Eila TurtolaSammendrag
During the past twenty years, the Nordic countries (Denmark, Sweden, Finland and Norway) have introduced a range of measures to reduce losses of nitrogen (N) to air and to aquatic environment by leaching and runoff. However, the agricultural sector is still an important N source to the environment, and projections indicate relatively small emission reductions in the coming years. The four Nordic countries have different priorities and strategies regarding agricultural N flows and mitigation measures, and therefore they are facing different challenges and barriers. In Norway farm subsidies are used to encourage measures, but these are mainly focused on phosphorus (P). In contrast, Denmark targets N and uses control regulations to reduce losses. In Sweden and Finland, both voluntary actions combined with subsidies help to mitigate both N and P. The aim of this study was to compare the present situation pertaining to agricultural N in the Nordic countries as well as to provide recommendations for policy instruments to achieve cost effective abatement of reactive N from agriculture in the Nordic countries, and to provide guidance to other countries. To further reduce N losses from agriculture, the four countries will have to continue to take different routes. In particular, some countries will need new actions if 2020 and 2030 National Emissions Ceilings Directive (NECD) targets are to be met. Many options are possible, including voluntary action, regulation, taxation and subsidies, but the difficulty is finding the right balance between these policy options for each country. The governments in the Nordic countries should put more attention to the NECD and consult with relevant stakeholders, researchers and farmer's associations on which measures to prioritize to achieve these goals on time. It is important to pick remaining low hanging fruits through use of the most cost effective mitigation measures. We suggest that N application rate and its timing should be in accordance with the crop need and carrying capacity of environmental recipients. Also, the choice of application technology can further reduce the risk of N losses into air and waters. This may require more region-specific solutions and knowledge-based support with tailored information in combination with further targeted subsidies or regulations.
Forfattere
Kristin Sørheim Johan Barstad Ildri Kristine Bergslid Annik Magerholm Fet Bjørn Egil Flø Unni Støbet Lande Liv Solemdal Håvard Steinshamn Liv Guri VelleSammendrag
Lokal verdiskaping basert på utmarka i verdsarvområda Vestlandsk fjordlandskap kan ikkje sjåast isolert, men er tett knytt til heile samfunnsutviklinga på desse stadene. Det tradisjonelle landbruket i desse områda har skapt verdfulle naturgode som biologisk mangfald, opne turområde med høg rekreasjonsverdi, turstiar og anna. Fleire av desse naturgoda er viktige for reiselivsnæringa. Kulturlandskapet er også viktig for verdsarvstatusen i seg sjølv, ettersom dette er ein viktig del av kjerneverdiane til området (OUV). Utviklinga i landbruket gjer at tungdrivne areal også i verdsarvområda går ut av bruk. Opphøyr eller låg bruksintensitet går spesielt ut over utmarksressursane og dei seminaturlege naturtypane. Utmarka i Geirangerfjordområdet er særleg trua, da tradisjonell bruk med beiting, slått og hausting no i stor grad har teke slutt, og naturtypane gror att med buskar og kratt. Gjengroing fører til tap avvariasjon, artar og økologiske funksjonar. Intensivering av landbruket vil også forringe naturverdiane og landskapskvalitetane. For at landbruket ikkje berre skal vere eit «kulisselandbruk», men vere del av eit berekraftig driftssystem, må tilgjengelege arealressursar på innmark og utmark nyttast til matproduksjon og andre livsviktige økosystemtenester. Gjeldande landbrukspolitikk, med mål om stordrift og effektivisering av matproduksjonen, er ei sterkare drivkraft enn dei tiltaka som er sett inn for å bremse og motverke at tungdrivne areal går ut av bruk i verdsarvområda. Den lokale turist- og reiselivsnæringa kan også hamne i noko av same marginaliserte situasjonen som landbruksnæringa fordi dei ikkje lenger er dei mest sentrale aktørane. Eksterne aktørar representert ved cruiseindustri, turbussar og storskala reisearrangørar er ofte i enda større grad premissleverandørar. Det trengs ei heilskapleg tilnærming for å løyse utfordringane. Ein prosess som forskyv maktbalansen frå eksterne aktørar innan masseturisme og i retning lokalt næringsliv og verdiskaping og som inkluderer innbyggjarane, krev nytenking, utvikling av nye forretningsmodellar og evne til gjennomføring gjennom demokratiske planprosessar. Av ulike konkrete verkemiddel som kan prøvast ut, men da helst som element i ein større endringsprosess, vil vi peike på særskilde landbrukspolitiske verkemiddel i retning sveitsisk modell, turistskatt, anna betaling for fellesgode og bygdeutviklingsprosjekt som kan gi auka tilflytting og ny næringsaktivitet. Dialog og partnarskapsbygging kan fremme ansvarleg medverknad.Forskingsbehova for verdsarvområda og tilsvarande område med store og unytta ressursar i utmarka er mange, og arbeidsgruppa si vurdering er summert og konkretisert i denne rapporten