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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.

2024

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Abstract

1. Wild pollinators are crucial for ecosystem functioning and human food production and often rely on floral resources provided by different (semi-) natural ecosystems for survival. Yet, the role of European forests, and especially the European forest herb layer, as a potential provider of floral resources for pollinators has scarcely been quantified. 2. In this study, we measured the potential nectar production (PNP) of the forest herb layer using resurvey data across 3326 plots in temperate forests in Europe, with an average time interval of 41 years between both surveys in order to assess (i) the importance of the forest herb layer in providing nectar for wild pollinators, (ii) the intra-annual variation of PNP, (iii) the overall change in PNP between survey periods and (iv) the change in intra-annual variation of PNP between survey periods. The PNP estimates nectar availability based on the relative cover of different plant species in the forest herb layer. Although PNP overestimates actual nectar production, relative differences amongst plots provide a valid and informative way to analyse differences across time and space. 3. Our results show that the forest herb layer has a large potential for providing nectar for wild pollinator communities, which is greatest in spring, with an average PNP of almost 16 g sugar/m2/year. However, this potential has drastically declined (mean plot-level decline >24%). 4. Change in light availability, associated with shifts in canopy structure and canopy composition, is the key driver of temporal PNP changes. 5. Synthesis. Our study shows that if management activities are carefully planned to sustain nectar-producing plant species for wild pollinators, European forest herb layers and European forests as a whole can play key roles in sustaining wild pollinator populations.

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Abstract

Automated sorption balances are widely used for characterizing the interaction of water vapor with hygroscopic materials. These instruments provide an efficient way to collect sorption isotherm data and kinetic data. A typical method for defining equilibrium after a step change in relative humidity (RH) is using a particular threshold value for the rate of change in mass with time. Recent studies indicate that commonly used threshold values yield substantial errors and that further measurements are needed at extended hold times as a basis to assess the accuracy of abbreviated equilibration criteria. However, the mass measurement accuracy at extended times depends on the operational stability of the instrument. Published data on the stability of automated sorption balances are rare. An interlaboratory study was undertaken to investigate equilibration criteria for automated sorption balances. This paper focuses on the mass, temperature, and RH stability and includes data from 25 laboratories throughout the worl

Abstract

To increase soil organic carbon (SOC) storage, we need to improve our understanding on how to make best use of available plant biomass. Is it better to leave harvest residues on the field, or can we achieve higher SOC storage after processing biomass through, for instance, composting or pyrolysis to produce biochar? In the present study, we developed new parameters for different types of exogenous organic materials (EOMs), which allowed us to estimate the long-term effect of EOM addition on SOC storage using the soil carbon model RothC. For this purpose, we used a model version that included two additional EOM pools. First, we simulated the SOC evolution after addition of equal amounts of C in plant material and different EOMs (manure, compost, digestate, biochar) for a 38-year cropland trial in Switzerland. As expected, biochar showed the greatest increase in SOC due to its high stability. Next, we estimated how much C would remain after subjecting equivalent amounts of plant material and other EOMs to different processes. Loss rates of C for different processes were obtained from the literature. Due to different decomposition rates, the amounts of C remaining in the EOMs ranged from 7 % for anaerobic digestion of animal excreta to 100 % for plant material added directly to soil. These amounts of C were then added to the soil in the model experiments. Although the largest amount of C is lost during processing to biochar, biochar would clearly lead to highest long-term SOC stocks. Based on these first results we conclude that the trade-off between off-site stabilization and in-soil mineralization does not compromise the use of biochar for soil C storage. This means that despite the high C losses of about 50 % during biochar production, higher amounts of C remain in the soil because biochar has very low decomposition rates. In terms of C sequestration efficiency, biochar thus clearly outperforms the other biomass processing pathways. However, for practical recommendations, additional factors should be considered, such as nutrient availability of EOMs and environmental effects during processing, storage and soil application like nutrient leaching or gaseous emissions. Furthermore, we suggest a full life cycle assessment that considers e.g. energy costs for transport of biomass and energy savings from fossil fuel substitution by natural gas.