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.

2023

Abstract

Intensification and specialization of farming systems in Europe and elsewhere has resulted in poor crop rotations, with low plant and animal diversity. This has resulted in more uniform landscapes, soil carbon loss and low efficiency in nutrient cycling, particularly in regions dominated by annual crops. Inclusion of ley in crop rotations is expected to increase soil organic carbon (SOC) stocks, nitrogen availability and improve soil physical properties. The effect of ley-arable rotations versus continuous annual cropping on soil quality, soil organic carbon and soil biology was assessed by summarizing and discussing results from publications from long-term experiments in Norway and Sweden. These studies support the hypotheses that the inclusion of leys in crop rotations promotes soil fertility and carbon sequestration in Northern Europe, supplies nutrients to subsequent crops and improves soil physical properties. However, one or two years of ley in rotations may not be enough for maintaining SOC and good soil structure over time. For keeping the relatively high SOC concentrations occurring at many sites in Northern Europe, the proportion of ley in rotation should be at least 50%.

Abstract

Ethiopia has the highest livestock numbers in Africa, and a large part of the population depends fully or partly on cattle for their livelihoods. The country experiences high rates of soil erosion due to degradation of cropland and rangelands, and overgrazing is a serious problem. In this paper, we report results from the first two harvests of two field experiments established in June 2021 at two different highland locations in Ethiopia: Hawassa in the south, and Bahir Dar in the north. Four species; two legumes (Desmodium intortum and Stylosanthes guianensis) and two grasses (Brachiaria hybrid ‘Cayman’ and Panicum maximum ‘Mombasa’) were sown in monocultures and various mixtures in a simplex design. Dry matter yields and botanical composition from each cut were recorded. The first harvest was taken around 100 days after establishment, while the second harvest was taken during the drought period, i.e. in January 2022 at Hawassa and in March 2022 at Bahir Dar. The difference between monoculture and mixture community performances varied in magnitude from site to site and across harvests; we found evidence of positive interactions between grasses and legumes at Hawassa. These preliminary results show that grass-legume mixtures using tropical species have some potential under Ethiopian conditions.

To document

Abstract

Chlorella vulgaris is a freshwater microalga that synthesises large amounts of saturated lipids, which makes it suitable for production of bioenergy and biofuels. Since its cultivation usually requires freshwater, it competes with agriculture, economic development and ecological conservation for this limited natural resource. This study investigated the possibility of the partial replacement of freshwater by seawater (50 %) in the growth medium for a more sustainable biomass and lipid production. Chlorella vulgaris 211-11b was cultivated as shake-flask cultures in Bold's Basal Medium (BBM) formulated with 50 % freshwater and 50 % seawater under photoautotrophic, mixotrophic and heterotrophic conditions for eight days with glucose as organic carbon source in the latter two cases. The alga's best growth performance and highest lipid contents (49 % DW−1), dominated by palmitioleic and oleic acid, occurred under mixotrophic rather than photoautotrophic and heterotrophic conditions. This study demonstrates a more economic and ecologically sustainable biomass and lipid production of C. vulgaris by saving 50 % freshwater, which is available for other purposes.