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.
2018
Forfattere
Trine Aulstad Sogn Ivan Dragicevic Roar Linjordet Tore Krogstad Vincent Eijsink Susanne Eich-GreatorexSammendrag
Purpose The main purposes of the study were to assess the NPK fertilizer value of biogas digestates in different soils and to evaluate the risk of unwanted nutrient leaching. Methods The fertilizer value of digestates from anaerobic digesters was investigated in a greenhouse pot experiment with wheat in three different soils; silt, loam and sand. The digestates were based on different feedstock and had a low, dry matter content. The fertilizing effect of digestates was compared to mineral fertilizer and manure. To investigate the fate of excess nutrients in soil after the growing season, the pots were leached after harvest. A complementary soil column leaching experiment without plants was carried out in the laboratory. Results The concentration of ammonium in digestates provided a good indicator of the nitrogen fertilizer value of the digestates. In the silt and loam, the ammonium N fraction in digestates had a fertilizer replacement value equal to that of mineral fertilizer N, whereas the replacement value was higher in the nutrient poor sandy soil. Digestates often have a ratio between nitrogen, phosphorus and potassium which is not favourable for plant growth. However, the suboptimal balance did not result in reduced plant growth or unwanted leaching from soil. Conclusions The results show that digestates from biogas production based on fundamentally different feedstock are promising as NPK fertilizers. The N fertilization can simply be based on the digestate NH4+ concentration and, at least for wheat production, considerable variation in the concentrations of K and P can be tolerated.
Sammendrag
The long-term success of sites selected for species conservation depends on the persistence of target species. Red List species or threatened species lists are frequently defined as target species, but when Red Lists are updated, their species composition may change. Here we investigate the effects of Red List updates on the long-term robustness of fine-scale site selection. We used records of red-listed species (vascular plants, bryophytes, macrolichens, and polypore fungi) recorded in 1997–1998 in 1058 sample plots (50 × 50 m) from six forest landscapes in Norway, and four consecutive issues of the Norwegian Red List for species (1998, 2006, 2010, 2015). Sites were selected based on the first issue (1998) using both a scoring (“hotspot”) approach and a complementarity approach, and the ability of selected sites to include red-listed species of later issues was measured. In four boreal forests the mean proportion of red-listed species included in selected sites were reduced by18% during the study period, whereas no such effect was found in two hemiboreal forests, where increased clustering of red-listed species in sites compensated for target species changes. Changing target species adds to earlier documented challenges caused by population dynamics, and we suggest that alternatives to using occurrences of target species in site selection should be considered, and particularly at finer spatial scales.
Forfattere
Ravishankar Narayana Judith Fliegmann Ivan Paponov Massimo E. MaffeiSammendrag
The Earth magnetic field (or geomagnetic field, GMF) is a natural component of our planet and variations of the GMF are perceived by plants with a still uncharacterized magnetoreceptor. The purpose of this work was to assess the effect of near null magnetic field (NNMF, ∼40 nT) on Arabidopsis thaliana Col0 root ion modulation. A time-course (from 10 min to 96 h) exposure of Arabidopsis to NNMF was compared to GMF and the content of some cations (NH4 +, K+, Ca2+ and Mg2+) and anions (Cl−, SO4 =, NO3 − and PO4 =) was evaluated by capillary electrophoresis. The expression of several cation and anion channel- and transporter-related genes was assessed by gene microarray. A few minutes after exposure to NNMF, Arabidopsis roots responded with a significant change in the content and gene expression of all nutrient ions under study, indicating the presence of a plant magnetoreceptor that responds immediately to MF variations by modulating channels, transporters and genes involved in mineral nutrition. The response of Arabidopsis to reduced MF was a general reduction of plant ion uptake and transport. Our data suggest the importance to understand the nature and function of the plant magnetoreceptor for future space programs involving plant growth in environments with a reduced MF.
Forfattere
Marianna Pastuszak Andreas C. Bryhn Lars Håkanson Per Stålnacke Marius Zalewski Tycjan WodzinowskiSammendrag
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Redaktører
Oddmund HjukseSammendrag
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This paper compares technical efficiencies (TEs) and technological gap ratios (TGRs) for dairy farms in regions of Norway, accounting for differences in working environments. We used the state-of-the-art stochastic meta-frontier approach to estimate TEs and TGRs to account for regional heterogeneity, and the ‘true’ random-effect model to account for farm effects. The dataset used was farm-level balanced panel data for 24 years (1992–2014), with 5442 observations from 731 dairy farms. The results of the analysis provide empirical evidence of small regional differences in TEs, TGRs, and input use. Furthermore, the results may provide support for the more regionally specific agricultural policy, in terms of support schemes and structural regulations.
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