Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2019
Authors
Peter Simon Claus Schulze Celeste Brindley José M. Fernández Ralf Rautenberger Hugo Pereira Rene Hubertus Wijffels Viswanath KironAbstract
Light attenuation in photobioreactors is a major bottleneck in microalgal production. A possible strategy for artificial light-based microalgal production to deliver light deep inside the culture is through the periodical emission of high intensity light flashes (so-called flashing light). However, our results did not show improved photosynthetic rates compared to continuous light for dilute and concentrated Tetraselmis chui cultures exposed to flashing light with various repetition rates (frequencies 0.01 Hz–1 MHz), light-dark ratios (duty cycles: 0.001–0.7) or time-averaged light intensity (50–1000 μmol s−1 m−2). Likewise, flashing light applied to Chlorella stigmatophora and T. chui batch cultures could not enhance growth. However, we observed flashing light effects at different duty cycles and frequencies, depending on cell acclimation, culture concentration, and light intensity. In conclusion, artificial flashing light does not improve microalgal biomass productivities in photobioreactors, but low frequencies (f < 50 Hz) may be still used to improve light harvesting-associated biomolecules production.
Authors
Rune Slimestad Torgils Fossen Cato BredeAbstract
No abstract has been registered
Abstract
Humic substances are important indicators of soil fertility. The fluorescence properties of humic acids from black soils in Harbin, northeast China, were investigated, after long-term fertilization using treatments with or without mineral fertilizer (NPK) and organic manure. Excitation and emission matrices combined with parallel factor analysis were used to investigate the structure of the humic acid. Principal component analysis was performed to select the most suitable parameters for the description of humic acid. The dimension reduction for the original fluorescence parameters extracted two principal components. By using the two principal component scores as a new index for clustering, it was concluded that long-term fertilization treatments in black soil in Harbin clustered into three groups of manure + NPK and organic manure treatments, NPK treatment, and soil without any fertilization. Manure + NPK fertilization and manure fertilization alone led to a higher degree of humification than NPK only or the control. We conclude that long-term fertilization with organic matter with or without NPK could increase the humification degree of these soils.
Academic – FluxCalR: a R package for calculating CO2 and CH4 fluxes from static chambers
Junbin Zhao
Authors
Junbin ZhaoAbstract
As the main drivers of climate change, greenhouse gas (e.g., CO2 and CH4) emissions have been monitored intensively across the globe. The static chamber is one of the most commonly used approaches for measuring greenhouse gas fluxes from ecosystems (e.g., stem/soil respiration, CH4 emission, etc.) because of its easy implementation, high accuracy and low cost (Pumpanen et al., 2004). To perform the measurements, a gas analyzer is usually used to measure the changes of greenhouse gas concentrations within a closed chamber that covers an area of interest (e.g., soil surface) over a certain period of time (usually several minutes). The flux rates (F) are then calculated from the recorded gas concentrations assuming that the changing rate is linear: F = vol/(R · T a · area) · dG/dt where vol is the volume of the chamber (l), R is the universal gas constant (l atm K-1 mol-1), Ta is the ambient temperature (K), area is the area of the chamber base (m2 ), and dG/dt is the rate of the measured gas concentration change over time t (ppm s-1) (i.e., the slope of the linear regression).
Authors
Sparkle Malone Abad Chabbi Gregory Starr Teng Hu Nicolas Puche Steven. F. Oberbauer Paulo Olivas Jessica Schedlbauer Junbin Zhao Christina Staudhammer Sean Charles Zhuoran YuAbstract
No abstract has been registered
Authors
Klara Petkovic Maja Manojlovic Ranko Čabilovski Dorde Krstic Zdenko Loncaric Peder LombnæsAbstract
Biofortification of forage crops has an important role in improving the quality of plants used for animal nutrition. The field experiments were conducted in three consecutive years in Subotica, Serbia, in order to investigate the effect of Se, Zn, and Cu foliar fertilization on the yield, Se and Zn contents and nutrient efficiency, as well as on other mineral compositions of alfalfa hay. The treatments were as follows: i) control without fertilization, ii) 5 g Se ha-1, iii) 10 g Se ha-1, iv) 0.5 kg Zn ha-1, v) 1 kg Zn ha-1, vi) the combination of these two elements (0.5 kg Zn ha-1 and Se 10 g ha-1) and vii) 2% Cu solution. The application of Se, Zn, and Cu had no effect on dry yield or on crude protein, P, K, Ca, Mg, Fe, Mn, Mo, and Co contents in alfalfa hay. However, Se, Zn, and Cu fertilization significantly increased the contents of Se, Zn, and Cu in alfalfa hay. The results showed that Se and Zn contents in plant biomass were significantly correlated with the applied doses of Se (r=0.99) and Zn (r=0.99). The production years of alfalfa and the weather conditions proved to be significant factors in fertilization efficiency.
Abstract
The objective of this paper was to examine how cutting frequency, silage fermentation patterns and clover performance in grass-clover swards influence the use of inputs and profitability in an organic dairy system. A linear programming model was developed to compare a three-cut and a two-cut system for a model farm in Central Norway, either with restricted or extensive silage fermentation at low or high red clover (Trifolium pratense L.) proportion in the sward, giving 8 different silage types in all. Input-output relations incorporated into the model were derived from a meta-analysis of organic grassland field trials in Norway as well as a silage fermentation experiment, and with feed intakes and milk yields from simulations with the ‘TINE Optifôr’ feed ration planner in the Norfor feed evaluation system. The model maximized total gross margin of farms with 260,000 l milk quota and housing capacity for 45 cows, with separate model versions for each of the 8 silage types. Farmland availability varied from 30 to 70 ha with 40 ha as the basis. Our results suggested that farmland availability and marginal return of a competing barley crop profoundly influenced the profitability of the different silage types. A high clover proportion increased dry matter (DM) yields and was far more important for profitability than the score on the other factors considered at restricted land availabilities. Profits with the three-cut systems were always greater than those with the two-cut systems, the former being associated with greater silage intakes and improved dairy cow performances but lower DM forage yields. Three-cut systems were further favoured as land availability increased and also by a lower marginal return of barley. Although use of an acidifying silage additive improved feed intakes and milk production per cow, the practice reduced total milk production and depressed profit compared to untreated, extensively fermented silage at restrictive land availabilities. With more land available, and in particular at a low marginal return of barley, use of a silage additive was profitable.
Authors
Krzysztof KusnierekAbstract
No abstract has been registered
Authors
Krzysztof KusnierekAbstract
No abstract has been registered
Authors
Rasmus Astrup Johannes Rahlf Knut Bjørkelo Misganu Debella-Gilo Arnt Kristian Gjertsen Johannes BreidenbachAbstract
This paper describes the development and utility of the Norwegian forest resources map (SR16). SR16 is developed using photogrammetric point cloud data with ground plots from the Norwegian National Forest Inventory (NFI). First, an existing forest mask was updated with object-based image analysis methods. Evaluation against the NFI forest definitions showed Cohen's kappa of 0.80 and accuracy of 0.91 in the lowlands and a kappa of 0.73 and an accuracy of 0.96 in the mountains. Within the updated forest mask, a 16×16 m raster map was developed with Lorey's height, volume, biomass, and tree species as attributes (SR16-raster). All attributes were predicted with generalized linear models that explained about 70% of the observed variation and had relative RMSEs of about 50%. SR16-raster was segmented into stand-like polygons that are relatively homogenous in respect to tree species, volume, site index, and Lorey's height (SR16-vector). When SR16 was utilized in a combination with the NFI plots and a model-assisted estimator, the precision was on average 2–3 times higher than estimates based on field data only. In conclusion, SR16 is useful for improved estimates from the Norwegian NFI at various scales. The mapped products may be useful as additional information in Forest Management Inventories.