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.
2018
Abstract
In cold-temperate climate with high soil water content in spring, the farmer often faces the choice between topsoil compaction during seedbed preparation and delayed sowing, both of which may reduce attainable cereal yield. The objective of this study was to explore whether future climate change with increasing precipitation would aggravate this dilemma. We generated weather based on historical and projected future climate in Southeastern and Central Norway. Using this weather data as input, we simulated spring workability, attainable yield, timeliness costs, and mechanization management with a workability model and a mechanization model. The projected climate changes resulted in improved workability for spring fieldwork and higher attainable yield in South-eastern Norway, and either positive or negative changes in Central Norway compared to historical conditions. We observed a general increase in variability of workability and attainable yield, and a larger risk of extremely unfavourable years in the most unfavourable scenarios in Central Norway. Changes in profitability and mechanization management were small, but followed the same pattern. The negative effects in the most unfavourable climate scenarios in Central Norway were in contrast to positive effects in earlier studies. We explained discrepancies by differences in research methods and purpose. However, simulated sowing dates of annual crops should consider workability of the soil, in terms of water content. Under worst-case conditions, in need of a certain time window to complete their spring fieldwork, farmers might adapt to impaired spring workability by working the soil at higher water content than simulated in our study. The consequence would be a larger loss of attainable yield and less profitability in the future. We anticipate that negative effects may also be expected in other northern cold-temperate regions with high soil water content in spring.
Abstract
No abstract has been registered
Authors
O. Janne Kjønaas Sunil Mundra Teresa Gómez de la Bárcena Mette Hansen Gro Hylen Håvard KauserudAbstract
No abstract has been registered
Authors
O. Janne Kjønaas Sunil Mundra Teresa Gómez de la Bárcena Mette Hansen Gro Hylen Håvard KauserudAbstract
Tree species change has been suggested as one of the government policies to mitigate climate change in Nor-way with the aim to increase the annual uptake of CO2 and the long-term storage of carbon (C) in forests. The strategy includes replacing native, deciduous species with fast-growing species, mainly Norway spruce. A shift in tree species is expected to affect the pools and fluxes of C in the stand as well as the microbial community. As part of the BalanC project, we assess C storage related to shift in tree species cover in western Norway and whether a corresponding shift in soil microbial communities are happening. The study aim at integrating results on soil respiration, C mineralization, soil stability, diversity of bacteria, fungi and micro-eukaryotes, soil nutrient pools, litter inputs and edaphic factors at the stand level in order to identify key drivers for changes in the soil C stocks. Fifteen paired plots of native birch and planted Norway spruce at five locations were sampled. Prelimi-nary results suggests a redistribution of C from the mineral soil to the forest floor in the spruce stands, with minor changes in the total soil C pools over the 45-60 years since the tree species change. The in situ soil respi-ration and heterothropic respiration, as well as C mineralization rates, were higher in birch than in spruce stands. Differences in C mineralization rates attenuate with depth between forest types. The microbial com-munities of the three organismal groups were all strongly structured along the vertical depth.
Authors
Anto Raja Dominic Ole Martin Eklo Marianne Stenrød Eivind Solbakken Roar Lågbu Peter Horney D Daehmlow Jörn StrassemeyerAbstract
No abstract has been registered
Authors
Anto Raja Dominic Ole Martin Eklo Marianne Stenrød Eivind Solbakken Roar Lågbu Peter Horney Burkhard Golla Jörn StrassemeyerAbstract
No abstract has been registered
Authors
Ole Martin Eklo Jens Kværner Eivind Solbakken Marianne Stenrød Roar Lågbu Randi Bolli Marit Almvik Sven R. Odenmarck Ivar Solberg Stein SorknesAbstract
No abstract has been registered
2017
Authors
Dorothee Kolberg Lars Olav Brandsæter Göran Bergkvist Knut Asbjørn Solhaug Bo Melander Björn RingselleAbstract
Quackgrass is a problematic agricultural weed in the temperate zones of the world and is difficult to control without herbicides or intensive tillage. However, it may be possible to control quackgrass with less environmental impact by combining multiple low-intensity control methods. A pot experiment was conducted in July to October 2012 and repeated in June to September 2013 to investigate the effect of rhizome fragmentation, competition from white clover, shoot-cutting frequency, and cutting height on quackgrass. Rhizome fragmentation was expected to result in more, but weaker, quackgrass shoots that would be more vulnerable to shoot cutting and competition. However, by 20 d past planting, rhizome fragmentation did not change the total number of quackgrass shoots per pot, because an increase in main shoots was offset by a decrease in tiller numbers. Rhizome fragmentation did not reduce quackgrass biomass acquisition during the experimental period. Although rhizome fragmentation did reduce total fructan content, it did not enhance the effect of clover competition, shoot-cutting frequency, or shoot-cutting height. Clover competition by itself reduced quackgrass shoot numbers by 72%, rhizome biomass by 81%, and belowground fructan concentration by 10 percentage points, compared with no competition. The more frequently quackgrass shoots were cut, the less biomass quackgrass acquired, and a high shoot-cutting frequency (each time quackgrass reached 2 leaves) resulted in a lower belowground fructan concentration than a low shoot-cutting frequency (at 8 leaves). However, in pots without competition, a higher shoot-cutting frequency resulted in more quackgrass shoots. A lower shoot-cutting height (25 mm) had more impact when shoot cutting was more frequent. In conclusion, rhizome fragmentation did not reduce the number of quackgrass shoots or rhizome biomass, but competition from white clover, a high shoot-cutting frequency, and a low shoot-cutting height strongly suppressed quackgrass biomass and fructan acquisition.
Abstract
Conversion from agriculture to forestry is considered a measure for mitigation of atmospheric CO2 but the impacts on soil C and N processes remain still unclear. We investigated heterotrophic respiration (RH), specific carbon mineralization (CMIN) and nitrogen mineralization (NMIN) in Norway spruce (Picea abies (Karst.) L.) and oak (Quercus robur L.) chronosequences on former cropland by laboratory incubation. The RH was estimated as the release of C per gram soil and CMIN as the release of C per gram of soil organic matter (SOM). Seven Norway spruce stands (16–44 years), eight oak stands (4–43 years), a cropland, a 35 years old permanent pasture and a 200-year-old oak-dominated forest were sampled (0–5 cm and 5–15 cm soil layers) in early spring. The SOM content gradually increased with stand age in 0–5 cm but remained the same in the 5–15 cm soil layer. The RH in the 0–5 cm layer gradually increased with time since afforestation in both tree species while there was no change in CMIN. In 5–15 cm, neither RH nor CMIN changed significantly after afforestation, but oak stands had significantly higher RH than Norway spruce. The NMIN and nitrification in 0–5 cm significantly increased with stand age and only nitrification was higher in oak. In 5–15 cm, only NMIN in oak increased with stand age, but both NMIN and nitrification were significantly higher in oak than spruce. Cropland RH, CMIN and NMIN rates were comparable to those found within the first decades of afforestation, whereas the 200-year-old forest and the pasture generally had RH and NMIN rates similar to the older chronosequence stands. We conclude that potential RH and soil N mineralization increased with time since afforestation and were tree species specific. Soil organic C stock gains observed in this area during the first 45 years after afforestation were not driven by decreased SOM decomposability, leaving increased litter C inputs as a more likely explanation. The lower CMIN in the 200-year-old forest suggests that future studies should include older forests to assess if the stability of C and the retention of N may increase in a longer term perspective.
Authors
Anto Raja Dominic Ole Martin Eklo Marianne Stenrød Eivind Solbakken Roar Lågbu P Horney D Daehmlow Jörn StrassemeyerAbstract
No abstract has been registered