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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.

2025

Abstract

Warmer temperatures due to global warming and use of climate-enhancing fbre covers makes it important to gain specifc knowledge of the temperature response in potato cultivars grown under Midnight Sun in northern Scandinavia. The temperature response was therefore studied in climate-controlled growth chambers under constant temperatures from 9 to 21 °C under a natural 24-h photoperiod in a greenhouse in Tromsø (69.7°N, 18.9°E), Norway, for the potato cultivars Gullauge (medium late) and Mandel (late). There was a strong response in both cultivars to temperature, with reduced developmental time from emergence and leaf formation to visible fower buds at increasing temperature intervals. Emergence was earlier for Gullauge than for Mandel, followed by no diference in development time between cultivars for subsequent developmental stages. Shoot dry matter weight per plant was highest at 12 °C and 15 °C for both cultivars, although with higher shoot biomass at harvest in Mandel than in Gullauge. Tuber yields and tuber dry-matter percentages were higher for Gullauge than for Mandel. Fresh weight yields and dry matter percentage for both cultivars were highest at 15 °C. Optimum temperature for above-ground vegetative development-rate was estimated to be 24.0 °C and 22.6 °C, for Gullauge and Mandel, respectively. In contrast, the respective temperature optima for developing tuber dry matter content were 16.6 °C and 15.6 °C. Lower temperature optima for below-ground developme below ground with optimumsa of around nt make potato a suitable crop for temperate and boreal climates with cooler autumn temperatures. Diferent temperature response for above- and below-ground development may be used for decision about when to remove climate-enhancing covers in response to the temperature during the season. This diference may also be important for developing temperature-based growth models for potato cultivars from emergence to tuber yields.

Abstract

Metabarcoding targeting nematodes, bacteria, fungi and oomycetes was used in combination with multispectral drone imagery and traditional soil extraction of nematodes to diagnose poor growth in patches of a potato field in Norway. Areas of good and poor growth as identified by the normalised difference vegetation index (NDVI) based on aerial photography were compared, and nematodes were identified as the likely drivers of poor growth. This was based on the presence of known plant-parasitic nematodes in the field and the significant association between low alpha diversity (total genus richness and abundance) for nematodes with areas of poor growth, while alpha diversity for other organism groups did not vary between patches with good and poor growth. Metabarcoding represented nematodes well compared to traditional soil extraction. The combination of aerial photography and metabarcoding used in this work offers a promising possibility to identify biological drivers of growth differences across organism groups at field scale.

To document

Abstract

Low pollinator richness and abundance is a primary driver of pollination deficits and may lead to reduced yields (production deficits). In response, domesticated honeybees are often used to increase pollination success, even though honeybees are less efficient pollinators than naturally occurring wild bees. Here, we explored whether Norwegian apple orchards experience pollination and production deficits, and if such deficits could be related to specific pollinator groups and activity. We conducted a supplemental pollination experiment and measured seed set and yield (fruit set x weight) for three cultivars, in six orchards, in two distinct apple growing regions in central Norway, for two years. In addition, we used cameras to record relative pollinator activity throughout the flowering period. Overall, we found a pollination and production deficit across all cultivars, although there were differences in pollination deficit among cultivars. Three orchards had a pollination deficit both years of the study, suggesting sub-optimal orchard structure and/or a lack of pollinators. However, we found that solitary bees significantly reduced both pollination and production deficit, suggesting that orchard management actions should focus on increasing wild bee diversity and abundance.

To document

Abstract

Sustainable land management can play an important role in climate change mitigation by reducing soil organic carbon (SOC)losses or even by sequestering C in soils. This can be achieved through practices that increase C inputs to the soil and/or improve the quality of these inputs, thereby facilitating the removal of atmospheric carbon dioxide (CO 2) and storing it in the soil asSOC. In this study, we investigated the potential of an increased share of legumes in crop rotations to enhance SOC accrual—defined as the increase in SOC stocks at a given land unit compared to the baseline scenario—using data from 30 mid-term(MTEs, 5–20 years) and long-term (LTEs, 20+ years) field experiments across Europe. Our findings indicate that increasing the proportion of forage legumes in rotations (based on 21 experiments and 39 paired comparisons) led to SOC accrual of up to13.25 Mg ha−1 (0.44 Mg ha−1 year−1), while grain legumes (based on nine experiments and 28 paired comparisons) resulted in a decrease in SOC stocks of up to 14.37 Mg ha−1 (−0.48 Mg ha−1 year−1) compared to the reference treatment. For forage legumes,the largest SOC gains were achieved at sites with the smallest reference SOC stocks and greater share of forage legumes in the rotation. Our observations suggested that the duration of crop growth of the forage legumes (annual vs. perennial) did not exert a significant impact on SOC stock increase, while pedoclimatic zone did. Positive effects on SOC stocks were more pronounced in the Atlantic climatic zone in contrast to the Mediterranean climatic zone. For grain legumes, larger SOC losses were observed with a greater share of grain legumes in the rotation. Overall, integrating forage legumes in cropping systems can enhance their sustainability and present a viable option for climate change mitigation. Finally, we present a regression equation to derive emission factors (EFs) for estimating SOC changes due to the increase of the share of forage legumes in a rotation, and another due to the increase of the share of grain legumes in the rotation. The first can be used to support the assessment of management impacts for the purpose of rewarding carbon farming and the estimation of a national-scale SOC accrual potential, while the second can be used for estimating national-scale SOC losses.

Abstract

Based on data from 58 stands located in three different regions within Norway, this study presents new models for quantifying growth characteristics of young, planted trees of Norway spruce (Picea abies (L.) Karst), a species that forms the backbone of the Norwegian forestry sector. The study focused on well-established, sufficiently stocked plantations to capture their inherent growth patterns. The presented models predict total tree height and the number of years required to reach a diameter at breast height of 5 cm for dominant and average-sized individuals, using common tree- and stand-level metrics. The study’s findings indicate enhanced growth of young spruce stands compared to growth dynamics observed in the 1960–1970s, likely due to improved growing conditions. The models presented here are an improvement over existing similar models and can be used in future forest growth and yield simulations. The study also aimed to provide a means to predict diameter distributions of young spruce plantations. While the results suggested significant differences between observed and predicted distributions, this still represents progress as there are currently no tools to estimate diameter distributions of young spruce plantations in Norway. Further research is recommended to corroborate the findings across a larger number of sites and to consider larger sample plots for potentially more accurate diameter distribution predictions.