Hopp til hovedinnholdet

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.

2021

Abstract

A large proportion of the soils in Norway require artificial drainage to improve the conditions for crop growth and field operations, but also to reduce the risk of soil compaction, surface runoff and erosion. The need for artificial drainage depends on climate, topography, soil type, groundwater conditions, and also the crop. At present, about 60-70 % of the agricultural land in Norway is artificially drained. Future climate change is expected to lead to higher temperatures, more precipitation and more frequent extreme events in Norway. This poses a challenge with respect to the drainage systems as more intensive drainage than present today may be required in some areas, although it is unclear whether this will be an efficient solution. In this study we aimed to evaluate the possible future changes in subsurface runoff and water balance elements at the Kvithamar experimental site. We set up the and calibrated the DrainMod model for the experimental data from poorly and optimally drained experimental fields. The calibrated model was further used to evaluate changes in subsurface runoff and the water cycle as a whole under changing conditions. We tested the effect of different drainage system designs (drain depth and spacing) on water regime under present and future climate conditions. It was quite difficult to calibrate the DrainMod model for surface runoff and drain flow measured from the Kvithamar lysimeter plots and to find a parameter set that could give a reasonable partitioning of the water. We concluded that due to the complexity of the hydrological regime of a drained field the effect of drains can be masked by other factors, like land use and spatio-temporal variability of soil properties. Our simulation results indicate that drainage system design has a big effect on surface and subsurface runoff as well as on evapotranspiration. Concerning future changes in the hydrological regime, the results varied depending on the future climate scenarios selected.

To document

Abstract

Bicarbonate was evaluated as an alternative carbon source for a green microalga, Tetradesmus wisconsinensis, isolated from Lake Norsjø in Norway. Photosynthesis, growth, and lipid production were studied using four inorganic carbon regimes: (1) aeration only, (2) 20 mM NaHCO3, (3) 5% (v/v) CO2 gas, and (4) combination of 20 mM NaHCO3 and 5% CO2. Variable chlorophyll a fluorescence analysis revealed that the bicarbonate treatment supported effective photosynthesis, while the CO2 treatment led to inefficient photosynthetic activity with a PSII maximum quantum yield as low as 0.31. Conversely, bicarbonate and CO2 treatments gave similar biomass and fatty acid production. The maximum growth rate, the final cell dry weight, and total fatty acids under the bicarbonate-only treatment were 0.33 (± 0.06) day−1, 673 (± 124) mg L−1 and 75 (± 5) mg g−1 dry biomass, respectively. The most abundant fatty acid components were α-linolenic acid and polyunsaturated fatty acids constituting 69% of the total fatty acids. The fatty acid profile eventuated in unsuitable biodiesel fuel properties such as high degree of unsaturation and low cetane number; however, it would be relevant for food and feed applications. We concluded that bicarbonate could give healthy growth and comparative product yields as CO2.

Abstract

This research aimed to determine if creeping bentgrass (Agrostis stolonifera L.) can be used as an alternative to colonial bentgrass (Agrostis capillaris L.) in a mixture with red fescue [equal rates of Chewings fescue (Festuca rubra ssp. commutata Gaud.) and slender creeping red fescue (Festuca rubra ssp. littoralis [G. Mey.] Auquier)] on Nordic golf greens managed without pesticides. The two mixtures were compared in two experiments: Experiment 1 under the creeping bentgrass management regime (mowing height, 3 mm; fertilization, 15 g N m−2 yr−1) and Experiment 2 under the red fescue management regime (5 mm and 10 g N m−2 yr−1) at three sites during 2015–2018. A seed mixture of red fescue and velvet bentgrass (Agrostis canina L.) was included in Experiment 2 only. The results showed that red fescue plus creeping bentgrass produced greens of equal turfgrass quality and with less Microdochium patch than red fescue plus colonial bentgrass under both regimes. In Experiment 2, red fescue plus velvet bentgrass resulted in higher turfgrass quality than the other mixtures but was more susceptible to Microdochium patch than red fescue plus creeping bentgrass. Tiller counts in the mixed plots at Landvik showed that red fescue was not outcompeted by bentgrass in any of the mixtures and that it was easier to manipulate the balance between red fescue and bentgrass in the mixture with creeping bentgrass than that with colonial bentgrass. More research should be put into optimal management, especially irrigation and thatch control, of mixed red fescue–bentgrass greens.

Abstract

In 2018–2019, establishment problems were encountered, after reseeding creeping bentgrass (Agrostis stolonifera) on a sand-based putting green after ice encasement at the NIBIO Turfgrass Research Center, Norway. Seeds germinated, but the seedlings attained a purple color and died in large patches. Replacement of the top 3 cm layer with new sand amended with Sphagnum peat or garden compost did not solve the problem. To explain this phenomenon, we (1) analyzed the original substrate for nematodes in patches with and without reestablishment failure; and (2) conducted a factorial pot trial with creeping bentgrass and Chewings fescue (Festuca rubra ssp. commutata) seeded on different substrates, some of them in layers, and with and without phosphorus (P) fertilization. The nematode counts showed six times more stubby-root nematodes and two times more spiral nematodes and needle nematodes in the patches with dead seedlings than in the patches with healthy seedings. In the pot trial, the fastest and slowest reestablishment was observed with new sand amended with garden compost and in the two treatments that included the original substrate, respectively. Replacement of the top 3 cm of the old substrate with new garden compost resulted in stagnation of bentgrass seedlings from four weeks after seeding, while fescue seedlings were unaffected. We conclude that the failure to reestablish creeping bentgrass was primarily due to nematodes, which are likely to be more critical for seedlings than for established turf. The green was later reestablished successfully with a 100 % red fescue seed blend.

To document

Abstract

Pesticides in agricultural surface water runoff cause a major threat to freshwater systems. Installation of filter systems or constructed wetlands in areas of preferential run-off is a possible measure for pesticides abatement. To develop such systems, combinations of filter materials suitable for retention of both hydrophilic and hydrophobic organic pesticides were tested for pesticide removal in planted microcosms. The retention of six pesticides frequently detected in surface waters (bentazone, MCPA, metalaxyl, propiconazole, pencycuron, and imidacloprid) was evaluated in unplanted and planted pot experiments with novel bed material mixtures consisting of pumice, vermiculite, water super-absorbent polymer (SAP) for retention of ionic and water soluble pesticides, and synthetic hydrophobic wool for adsorption of hydrophobic pesticides. The novel materials were compared to soil with high organic matter content. The highest retention of the pesticides was observed in the soil, with a considerable translocation of pesticides into the plants, and low leaching potential, in particular for the hydrophobic compounds. However, due to the high retention of pesticides in soil, environmental risks related to their long term mobilization cannot be excluded. Mixtures of pumice and vermiculite with SAP resulted in high retention of i) water and ii) both hydrophilic and hydrophobic pesticides but with much lower leaching potential compared to the mineral systems without SAP. Mixtures of such materials may provide near natural treatment options in riparian strips and also for treatment of rainwater runoff without the need for water containment systems.

To document

Abstract

To investigate the possible family influence on sea lice grazing of lumpfish on Atlantic salmon, ten families of lumpfish (N = 480) with a mean (± SD) weight of 54.8 ± 9.2 g were distributed among ten sea cages (5 × 5 × 5 m) each stocked with 400 Atlantic salmon with a mean (± SD) weight of 621.4 ± 9.2 g. All the ten cages were stocked with 48 lumpfish (12% stocking density). The stocking of cages was such that each cage consisted of two random families where full- and paternal half-sib families were randomly allocated to the different cages. There were clear differences in sea lice grazing efficacy, growth and cataract prevalence between the ten families assessed in this study. Lumpfish from families 2, 6 and 10 had the lowest mean weights but showed comparable growth rates compared to the other families throughout the study and this may be as a direct result of genetic influence. In addition, fish from these families had a significantly higher incidence of lice grazing of both L. salmonis and C. elongatus compared to the other families. Using mixed linear model to analyse the data revealed significant family and paternal effect on sea lice grazing. There was a trend for a reduction in sea lice grazing with increased size within each family. The results indicated that it was the smallest size classes of lumpfish (40–140 g) which exhibited higher sea lice grazing potential compared to the larger size classes within families. There were no clear differences in the lice grazing potential between male and female lumpfish within and between families. Overall, present findings showed that sea lice grazing of both L. salmonis and C. elongatus can be enhanced using targeted family production and if this behaviour has a genetic basis it may further enhanced through selection and targeted breeding programs.