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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.

2016

Abstract

This report gives a comprehensive review of current knowledge on nitrous oxide (N2O) emissions from mineral soils with special reference to the Norwegian agriculture and some research results from other countries. The report starts by highlighting the importance of N2O followed by descriptions of the pathways to N2O production and factors affecting N2O emissions from agricultural soils and measurement techniques and modelling N2O emissions. This is followed by reviewing and discussing research results on the effects of soil management practices including fertilizer application, soil compaction, soil tillage, effects of soil moisture and drainage conditions, effects of soil pH, freezing-thawing effects and effects of soil drying and rewetting on N2O emissions. Furthermore, some relevant mitigation measures to reduce N2O emissions are presented. The report concludes by suggesting future research needs to measure and mitigate soil N2O emissions.

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Abstract

Ryegrass x fescue interspecific hybridization (so-called Festulolium) has great potential for forage diversification because of its many amphiploid and introgression-bred forms. Festulolium breeding efforts aim to improve adaptation to mainly winter cold and summer drought through higher abiotic stress tolerance. This goal must be met with a minimum of compromise regarding productivity in the first years of full exploitation. To compare field performances, a 21-entry trial of Festulolium and controls of pure species has been ongoing since 2012 in eight European countries. The yield data collected in 2012 and 2013 in nine locations showed that the Festulolium cultivars performed on average quite well compared to pure species controls. In amphiploids, the annual yield appeared to be mainly driven by the Lolium sp. parent combined with F. pratensis (Fp); the Lm x Fp amphiploids performed thus far better on average than the Lp x Fp equivalents. The only amphiploid from F. glaucescens included in the study had an intermediate response over locations, which was closer to tall fescue than to F. pratensis. Interestingly, a broad variability for yield among the Lm x Fp cultivars appeared to be associated with climate interactions when cold, wet locations were contrasted with more temperate locations with early spring growth.

Abstract

This report contains all the monitoring data collected in the course of three years, from 2013 to May 2016. The deposits had high contents of organic material and high water content before monitoring started. Data showed minimum temperatures close to 0-2°C under winter conditions and maximum temperatures at 14°C during the period from May to September in 2013. In 2014 the minimum temperature increased to 6-7°C and the maximum temperature increased to 17-18°C. Data recorded in 2015 showed minimum temperature 7-9°C and maximum temperature at 16-19°C. The average and median values calculated in 2013 were about 11°C, 13°C in 2014 and 14°C in 2015. High soil moisture was found in all layers, and fluctuated with precipitation. This increased more frequently in 2014 and 2015 under periods with high precipitation. This high precipitation frequency the last two years and infiltration of roof water has decreased the redox potential to more anoxic conditions, which is positive for the preservation of the archaeological remains. The previous status report II, written in 2015, informs that the redox sensor was malfunction because of the great curve drop in 2014 for sensors in layer 2 and 3. In 2015, the redox sensors all show more stable conditions of -400, -311 to -11 mV in layers 2, 3 and 4.

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Abstract

Key message Quality and reliability of forest resource assessments depend on the ability of national forest inventories (NFIs) to supply necessary and high-quality data. Over the last decades and especially since the 1990s, the NFIs in European countries have been rapidly developing. Possibilities for obtaining reliable and accurate data on annual increment from different inventory types were evaluated, and sample-based inventories have been found to be superior to standwise inventories in providing reliable data. Simplified methods may be employed when increment cannot be directly estimated from inventory data. Context An increasing intensity of forest resource use requires more accurate, detailed and reliable information, not only on forest area and growing stock but also on forest stand productivity, wood increment and its components. Aims The main objectives were to assess the capacities of forest inventories, the methods used for estimation of gross increment and its components and their accuracy and to demonstrate an effective method for estimation of increment when direct inventory methods are not available. Methods Data about national forest inventory methods were obtained from 30 responses to a questionnaire, distributed amongst national correspondents of all European countries; reports of COST Actions E43 and FP 1001, databases of Temperate and Boreal Forest Resource Assessment (TBFRA) 2000 and State of Europe’s Forests (SoEF) 2011 were used as well. Analysis and comparison of results from different forest inventories were used for evaluation of data reliability. Relationships between growing stock and gross increment in European forests were also analysed, and corresponding models were proposed. Results Seventy-nine percent of European forest area is covered by national forest inventories (NFIs) based on sampling methods and the rest on stand-level inventory and other inventory methods. Data obtained by aggregating standwise data usually underestimate growing stock by 15–20 % and gross increment even more. Almost half of the European forest area (47 %) is monitored using permanent plots, measured twice or more, allowing the estimation of gross increment and its components to be made directly. Conclusion Implementation of NFIs based on sampling methods, especially with permanent plots, resulted in an improvement of data quality and in most cases an increase of growing stock and gross increment. The estimation of natural losses is the weakest link in today’s NFIs and in the current assessment of European forest resources. The proposed default values for gross increment and its components is an option to be used in countries not having NFI at all or those which have started it only recently.

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Abstract

Accurate estimation of winter wheat frost kill in cold-temperate agricultural regions is limited by lack of data on soil temperature at wheat crown depth, which determines winter survival. We compared the ability of four models of differing complexity to predict observed soil temperature at 2 cm depth during two winter seasons (2013-14 and 2014-15) at Ultuna, Sweden, and at 1 cm depth at Ilseng and Ås, Norway. Predicted and observed soil temperature at 2 cm depth was then used in FROSTOL model simulations of the frost tolerance of winter wheat at Ultuna. Compared with the observed soil temperature at 2 cm depth, soil temperature was better predicted by detailed models than simpler models for both seasons at Ultuna. The LT50 (temperature at which 50 % of plants die) predictions from FROSTOL model simulations using input from the most detailed soil temperature model agreed better with LT50 FROSTOL outputs from observed soil temperature than what LT50 FROSTOL predictions using temperature from simpler models did. These results highlight the need for simpler temperature prediction tools to be further improved when used to evaluate winter wheat frost kill.