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.
2019
Authors
Robert Barneveld Sjoerd E.A.T.M. van der Zee Inga Greipsland Sigrun Hjalmarsdottir Kværnø Jannes StolteAbstract
Measures designed to control erosion serve two purposes: on site (reduce soil loss) and off site (reduce sediment delivery to streams and lakes). While these objectives often coincide or at least are complementary, they could result in different priority areas when spatial planning is concerned. Prioritising for soil loss reduction at the field level will single out areas with high erosion risk. When sediment flux at the catchment scale is concerned, sediment pathways need to be identified in ex ante analyses of soil conservation plans. In Norway, different subsidy schemes are in place to reduce the influx of solutes and sediments to the freshwater system. Financial support is given to agronomic measures, the most important of which is reduced autumn tillage where areas with higher erosion risk receive higher subsidies. The objectives of this study are (1) to assess the use of an index of connectivity to estimate specific sediment yields, and (2) to test whether conservation measures taken in critical source areas are more effective than those taken at where erosion risk levels are the highest. Different modelling approaches are combined to assess soil loss at catchment level from sheet and gully erosion and soil losses through the drainage system. A calibration on two parameters gave reasonable results for annual soil loss. This model calibration was then used to quantify the effectiveness of three strategies for spatial prioritisation: according to hydrological connectivity, sheet erosion risk level and estimated specific sediment yield. The latter two strategies resulted in a maximum reduction in total soil loss due to reduced autumn tillage of 10%. Both model performance and the effectiveness of the different prioritisation strategies varied between the study catchments.
Abstract
We investigated dissipation, earthworm and plant accumulation of organic contaminants in soil amended with three types of sewage sludge in the presence and absence of plants. After 3 months, soil, plants and earthworms were analyzed for their content of organic contaminants. The results showed that the presence of plant roots did not affect dissipation rates, except for galaxolide. Transfer of galaxolide and triclosan to earthworms was significant, with transfer factors of 10–60 for galaxolide and 140–620 for triclosan in the presence of plants. In the absence of plants, transfer factors were 2–9 times higher. The reduced transfer to worms in the presence of plants was most likely due to roots serving as an alternative food source. Nonylphenol monoethoxylate rapidly dissipated in soil, but initial exposure resulted in uptake in worms, which was detected even 3 months after sewage sludge application. These values were higher than the soil concentration at the start of the exposure period. This indicates that a chemical's short half-life in soil is no guarantee that it poses a minimal environmental risk, as even short-term exposure may cause bioaccumulation and risks for chronic or even transgenerational effects.
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No abstract has been registered
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Biochar has been shown to reduce nitrous oxide (N2O) emissions from soils, but the effect is highly variable across studies and the mechanisms are under debate. To improve our mechanistic understanding of biochar effects on N2O emission, we monitored kinetics of NO, N2O and N2 accumulation in anoxic slurries of a peat and a mineral soil, spiked with nitrate and amended with feedstock dried at 105 °C and biochar produced at 372, 416, 562 and 796 °C at five different doses. Both soils accumulated consistently less N2O and NO in the presence of high-temperature chars (BC562 and BC796), which stimulated reduction of denitrification intermediates to N2, particularly in the acid peat. This effect appeared to be strongly linked to the degree of biochar carbonisation as predicted by the H:C ratio of the char. In addition, biochar surface area and pH were identified as important factors, whereas ash content and CEC played a minor role. At low pyrolysis temperature, the biochar effect was soil dependent, suppressing N2O accumulation in the mineral soil, but enhancing it in the peat soil. This contrast was likely due to the labile carbon content of low temperature chars, which contributed to immobilise N in the mineral soil, but stimulated denitrification and N2O emission in the peat soil. We conclude that biochar with a high degree of carbonisation, high pH and high surface area is best suited to supress N2O emission from denitrification, while low temperature chars risk supporting incomplete denitrification.
Abstract
Biochar is a carbon-rich material that, due to its inherent resistance to decomposition, is primarily developed with the aim of sequestering carbon in soil. Despite the convincing benefits of biochar as a climate mitigation solution, it has not yet advanced much beyond the research stage, notably because its effect on yield are too modest. Therefore, there is a need for win-win biochar solutions benefiting both food production and climate mitigation. Such a solution is the development of biochar fertilizers, which capitalizes on the capacity of biochar to capture and release nutrients. This effect is largely attributed to the porous structure and large surface area of biochar, with surface charges and ash content also appearing to play a role. The nutrient-retaining capacity of biochar appears to vary among studies investigating different types of biochar exposed to different types of nutrients (mineral anions and cations, organic molecules) under different conditions. In the present study, we will report on a meta-analysis of published biochar properties that are associated with controlling the sorption of nutrients. As biochar properties largely depend on pyrolysis conditions and feedstock properties, this work contributes to the selective design of biochars for the purpose of improving nutrient use efficiency.
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No abstract has been registered
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A negative impact of multiple anthropogenic stressors on surface waters can be observed worldwide threatening fresh- and marine water ecosystem functioning, integrity and services. Water pollution may result from point or diffuse sources. An important difference between a point and a diffuse source is that a point source may be collected, treated or controlled. Agricultural activities related to crop production are considered as diffuse sources and are among the main contributors of nutrient loads to open water courses, being to a large degree responsible for the eutrophication of inland and coastal waters. Knowledge of hydrological and biogeochemical processes are needed for climate adaptive water management as well as for introducing mitigation measures aiming to improve surface water quality. Mathematical models have the potential to estimate changes in hydrological and biogeochemical processes under changing climatic or land use conditions. These models, indeed, need careful calibration and testing before being applied in decision making. The aim of this study was to evaluate the efficiency of various water protective adaptation strategies and mitigation measures in reducing the soil particle and nutrient losses towards surface water courses from agricultural dominated catchments. We applied the INCA-N and INCA-P models to a well-studied Norwegian watershed belonging to the Norwegian Agricultural Environmental Monitoring Program. Available measurements on water discharge, TN and TP concentration of stream water and local expert knowledge were used as reference data on land-use specific sediment, N and P losses. The calibration and the validation of both the models was successful; the Nash-Sutcliffe statistics indicated good agreement between the measured and simulated discharge and nutrient loads data. Further, we created a scenario matrix consisting of land use and soil management scenarios combined with different climate change scenarios. Our results indicate that land use change can lead to more significant reduction in particle and nutrient losses than changes in agricultural practices. The most favourable scenario for freshwater ecosystems would be afforestation: changing half of the agricultural areas to forest would reduce sediment, total N and total P losses by approximately 44, 35 and 40%, respectively. Changes in agricultural practices could also improve the situation, especially by reducing areas with autumn tillage to a minimum. We concluded, that the implementation of realistic land use and soil management scenarios still would not lead to satisfactory reduction in freshwater pollution. Hence, mitigation measures, enhancing water and particle retention in the landscape – as sedimentation ponds, constructed wetlands etc. – are important in facing the upcoming pressures on water quality in the future.
Abstract
No abstract has been registered
Authors
Trygve S. Aamlid Ellen Johanne Svalheim Eveliina Kallioniemi Hans Martin Hanslin Håkon Borch Knut Anders HovstadAbstract
No abstract has been registered