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.
2020
Forfattere
Tor MykingSammendrag
Det er ikke registrert sammendrag
Sammendrag
The study aimed to explore whether an increase in bunker silage density obtained by turning to a heavier packing machine than a farm size tractor would reduce losses and improve grass silage quality and aerobic stability. At each of three harvests, two bunkers were packed with either a 14.5 t wheel loader (WL) or an 8.3 t tractor (T). For comparison with the bunker silages, silage was produced simultaneously in round bales with high and low chamber pressure and wrapped immediately or after delay, and in laboratory silos. Compaction with WL increased silage dry matter (DM) density by 9 % compared with T, from 204 to 222 kg DM/m3. On average for three harvests, DM recovered as silage, or lost, was almost identical for the two packing treatments, with 870 g/kg of harvested DM recovered as feed offered to animals, 55 g/kg as wasted silage, and 75 g/kg as invisible losses due to respiration, effluent, fermentation and aerobic deterioration. However, in the harvest with lowest crop DM content, 266 g/kg, invisible DM losses with WL exceeded losses with T by 46 g/kg, of which the main portion was assumed to be caused by more effluent squeezed out by the WL. In the harvest with highest crop DM, 332 g/kg, invisible DM losses with T exceeded losses with WL by 43 g/kg, of which the main portion was assumed to be caused by poorer compaction with T, and therefore higher respiration and aerobic deterioration losses. Wasted silage DM was lower in bales than in bunkers (P = 0.004). The proportion of offered silage DM from poorly compacted bales sealed after delay (867 g/kg) was similar to that of bunkers, whereas the proportion of offered silage DM from well compacted and immediately sealed bales (963 g/kg) was similar to that of laboratory silos. Significant increases in protein bound in the neutral detergent and acid detergent fiber fractions were found in bales sealed after delay where temperatures had rised to 47 °C at wrapping. Similar levels of fiber bound protein were found in bunker silage, suggesting that they were also heated during filling. Spot samples from bunker silo shoulders were more infected by yeasts, moulds and Clostridium tyrobutyricum than samples from mid in bunkers and from bales. No differences in losses, silage composition or aerobic stability were observed between bunker silo packing with WL or T on average over three harvests.
Forfattere
Ellen Johanne SvalheimSammendrag
Det er ikke registrert sammendrag
Forfattere
Mekjell MelandSammendrag
Det er ikke registrert sammendrag
Forfattere
Haftamu Gebretsadik Gebrehiwot Jens Bernt Aune Ole Martin Eklo Torfinn Torp Lars Olav BrandsæterSammendrag
Allelopathic potential of 10 teff varieties was assessed in laboratory experimentation (conducted in NIBIO, Norway), and determined with an agar-based bioassay using ryegrass and radish as model weeds. Field experiments were conducted in Tigray, Ethiopia during 2015 and 2016 to identify the most important agronomic traits of teff contributing to its weed competitive ability. A split plot design with three blocks was used considering hand weeding as the main plot and varieties as the subplot. Randomized complete block design (RCBD) with four blocks was used in the laboratory experiment. The highest potential allelopathic activity (PAA) and specific potential allelopathic activity (SPAA) were recorded from a local landrace with an average PAA value of 11.77% and SPAA value of 1.21%/mg respectively, when ryegrass was used as the model weed. ‘Boset’ had the highest average PAA value of 16.25% and an SPAA value of 1.53%/mg, when using radish as the model weed. The lowest PAA and SPAA values were recorded from ‘DZ-Cr-3870 when using ryegrass and radish as model weeds. Days to emergence, height, tiller no./plant, biomass yield, and PAA of the crop significantly contributed to the variance of the weed biomass, cover, and density. Hence, they were the most important agronomic traits enhancing the competitive ability of teff.
Forfattere
D. Vanella D.S. Intrigliolo S. Consoli G. Longo-Minnolo G. Lizzio R.C. Dumitrache E. Mateescu Johannes Deelstra J.M. Ramírez-CuestaSammendrag
The reliability of short-term weather forecast provided by COSMO model in simulating reference evapotranspiration (ET0) was evaluated in 7 study sites distributed in 4 countries (Italy, Norway, Romania and Spain). The main objective of the study was to assess the optimal scenario for calculating ET0, using the FAO-56 Penman-Monteith (PM) equation, by separately considering the accuracy in the use of “past” and “forecast” data input. Firstly, each forecasted variable (air temperature, Tair; relative humidity, RH; wind speed, u2; solar radiation, Rs) and ET0 were compared with in situ observations at hourly and daily scales. Moreover the seasonality effect in the forecast performance was evaluated. Secondly, simulated ET0 were computed every three days with: (i) a “past scenario” that used the observed data input measured in situ during the previous three days, (ii) a “forecast scenario” that used the forecasted input variables for the next three days; and compared with (iii) actual ET0 obtained from the in situ measured data. A general good agreement was found between observed and forecasted agro-meteorological parameters at the different explored time-scales. The best performance was obtained for Tair and Rs, followed by RH and u2. Globally, the comparison between ET0 from the measured and forecasted data input showed high performance, with R2 and RMSE of 0.90 and 0.68 mm d−1. ET0 simulations resulted more accurate using the “forecast scenario” (1.7% overestimation), rather than using the “past scenario” (2.6% underestimation). These results open promising perspectives in the use of forecast for ET0 assessment for different agriculture practices and particularly for irrigation scheduling under water scarcity conditions.
Forfattere
Franca G. Rossi Belachew Asalf Tadesse Chloé Grieu Rodrigo B. Onofre Natalia A. Peres David M. Gadoury Arne StensvandSammendrag
In a number of pathosystems involving the powdery mildews (Erysiphales), plant stress is associated with decreased disease susceptibility and is detrimental to pathogen growth and reproduction. However, in strawberry, anecdotal observations associate severe powdery mildew (Podosphaera aphanis) with water stress. In a 2017 survey of 42 strawberry growers in Norway and California, 40 growers agreed with a statement that water-stressed strawberry plants were more susceptible to powdery mildew compared with nonstressed plants. In repeated in vitro and in vivo experiments, we found that water stress was consistently and significantly unfavorable to conidial germination, infection, and increases in disease severity. Deleterious effects on the pathogen were observed from both preinoculation and postinoculation water stress in the host. Soil moisture content in the range from 0 to 50% was correlated (R2 = 0.897) with germinability of conidia harvested from extant colonies that developed on plants growing at different levels of water stress. These studies confirm that P. aphanis fits the norm for biotrophic powdery mildews and hosts under stress. Mild water stress, compared with a state of optimal hydration, is likely to decrease rather than increase susceptibility of strawberry to P. aphanis. We believe it is possible that foliar symptoms of leaf curling due to diffuse and inconspicuous infection of the lower leaf surfaces by P. aphanis could easily be mistakenly attributed to water stress, which we observed as having a nearly identical leaf curling symptom in strawberry.
Forfattere
Leonardo H. Teixeira Florencia A. Yannelli Gislene Ganade Johannes KollmannSammendrag
Ecosystem properties can be positively affected by plant functional diversity and compromised by invasive alien plants. We performed a community assembly study in mesocosms manipulating different functional diversity levels for native grassland plants (communities composed by 1, 2 or 3 functional groups) to test if functional dispersion could constrain the impacts of an invasive alien plant (Solidago gigantea) on soil fertility and plant community biomass via complementarity. Response variables were soil nutrients, soil water nutrients and aboveground biomass. We applied linear mixed-effects models to assess the effects of functional diversity and S. gigantea on plant biomass, soil and soil water nutrients. A structural equation model was used to evaluate if functional diversity and invasive plants affect soil fertility directly or indirectly via plant biomass and soil pH. Invaded communities had greater total biomass but less native plant biomass than uninvaded ones. While functional diversity increased nutrient availability in the soil solution of uninvaded communities, invasive plants reduced nutrient concentration in invaded soils. Functional diversity indirectly affected soil water but not soil nutrients via plant biomass, whereas the invader reduced native plant biomass and disrupted the effects of diversity on nutrients. Moreover, invasive plants reduced soil pH and compromised phosphate uptake by plants, which can contribute to higher phosphate availability and its possible accumulation in invaded soils. We found little evidence for functional diversity to constrain invasion impacts on nutrients and plant biomass. Restoration of such systems should consider other plant community features than plant trait diversity to reduce establishment of invasive plants.
Forfattere
Hang Su Chengjian Fan Zhiwei Liao Chunrong Yang Jihong Liu Clarke Yongan Zhang Jianguo SuSammendrag
Diseases caused by viruses threaten the production industry and food safety of aquaculture which is a great animal protein source. Grass carp reovirus (GCRV) has caused tremendous loss, and the molecular function of viral proteins during infection needs further research, as for most aquatic viruses. In this study, interaction between GCRV major outer capsid protein VP4 and RIG-I, a critical viral RNA sensor, was screened out by GST pull-down, endogenous immunoprecipitation and subsequent LC-MS/MS, and then verified by co-IP and an advanced farred fluorescence complementation system. VP4 was proved to bind to the CARD and RD domains of RIG-I and promoted K48-linked ubiquitination of RIG-I to degrade RIG-I. VP4 reduced mRNA and promoter activities of key genes of RLR pathway and sequential IFN production. As a consequence, antiviral effectors were suppressed and GCRV replication increased, resulting in intensified cytopathic effect. Furthermore, results of transcriptome sequencing of VP4 stably expressed CIK (C. idella kidney) cells indicated that VP4 activated the MyD88-dependent TLR pathway. Knockdown of VP4 obtained opposite effects. These results collectively revealed that VP4 interacts with RIG-I to restrain interferon response and assist GCRV invasion. This study lays the foundation for anti-dsRNA virus molecular function research in teleost and provides a novel insight into the strategy of immune evasion for aquatic virus.
Sammendrag
Soil particles and bound nutrients that erode from agricultural land may end up in surface waters and cause undesirable changes to the environment. Various measures, among them constructed wetlands have been proposed as mitigation, but their efficiency varies greatly. This work was motivated by the assumption that the induced coagulation of particles may accelerate sedimentation in such wetlands and by that help reduce the amount of material that is lost from the vicinity of the diffuse source. Our specific aim was to laboratory-test the effectiveness of various salt-based coagulants in accelerating the process of sedimentation. We tested the effect of Na+, Mg2+, Ca2+, Fe3+ and Al3+ cations in 10, 20, 40 and 80 mg L-1 doses added to a soil solution in select, soluble forms of their chlorides, sulphates and hydroxides. We mixed such salts with 1 gram of physically dispersed, clay and silt rich (>85% in total) soil material in 500 mL of solution and used time-lapse photography and image analysis to evaluate the progress of sedimentation over 3 hours. We found that 20–40 mg L-1 doses of Mg2+, Ca2+ in their chloride or sulphate forms appeared to provide the best consensus in terms of efficiently accelerating sedimentation using environmentally present and acceptable salts but keeping their dosage to a minimum. Comprehensive in-field efficiency and environmental acceptability testing is warranted prior to any practical implementation, as well as an assessment of small scale economic and large-scale environmental benefits by retaining soil and nutrients at/near the farm.