Sammendrag

Klimaet forventes å bli våtere, varmere og villere. Faren for økt avrenning, flom og jorderosjon vil øke, med påfølgende fare for høyere tilførsler av næringsstoff fra landbruket til vannforekomster. Det finnes mange undersøkelser og publikasjoner om overvannstiltak, og basert på denne informasjonen presenterer vi her en oversikt over tiltak som har til formål å holde vannet lengst mulig i nedbørfeltet, både i skogen og i typiske jordbruksområder, og som er egnet til bruk i Norge. Vi indikerer viktigste virkemåte av tiltakene: «forsink og fordrøy» (F) og/eller «fang og infiltrer»

Sammendrag

Noen av vassdragene på Smøla er påvirket av landbruksforurensing, i hovedsak fosfor og organiske partikler som fører til at vassdragene gror igjen, noe som gir dårligere forhold for ørret. Rapporten skisserer 5 konstruerte våtmarker/fangdammer som skal kunne holde tilbake næringsstoffer og fosfor. Våtmarkene er plassert i vassdrag med stor andel dyrka jord i nedbørfeltet. Våtmarkene består i hovedsak av et dypere sedimentasjonsbasseng, fulgt av et grunt vegetasjonsfilter med våtmarksvegetasjon.

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Sammendrag

Only a few studies have quantified and measured ecosystem services (ES) specifically related to soil. To address this gap, we have developed and applied a methodology to assess changes in ecosystem services, based on measured or estimated soil property changes that were stimulated by soil management measures (e.g., mulching, terracing, no-till). We applied the ES assessment methodology in 16 case study sites across Europe representing a high diversity of soil threats and land use systems. Various prevention and remediation measures were trialled, and the changes in manageable soil and other natural capital properties were measured and quantified. An Excel tool facilitated data collection, calculation of changes in ecosystem services, and visualization of measured short-term changes and estimated long-term changes at plot level and for the wider area. With this methodology, we were able to successfully collect and compare data on the impact of land management on 15 different ecosystem services from 26 different measures. Overall, the results are positive in terms of the impacts of the trialled measures on ecosystem services, with 18 out of 26 measures having no decrease in any service at the plot level. Although methodological challenges remain, the ES assessment was shown to be a comprehensive evaluation of the impacts of the trialled measures, and also served as an input to a stakeholder valuation of ecosystem services at local and sub-national levels.

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Sammendrag

The hydrological processes associated with vegetation and their effect on slope stability are complex and so difficult to quantify, especially because of their transient effects (e.g. changes throughout the vegetation life cycle). Additionally, there is very limited amount of field based research focusing on investigation of coupled hydrological and mechanical influence of vegetation on stream bank behavior, accounting for both seasonal time scale and different vegetation types, and none dedicated to marine clay soils (typically soil type for Norway). In order to fill this gap we established hydrological and mechanical monitoring of selected test plots within a stream bank, covered with different types of vegetation, typical for Norwegian agricultural areas (grass, shrubs and trees). The soil moisture, groundwater level and stream water level were continuously monitored. Additionally, soil porosity and shear strength were measured regularly. Observed hydrological trends and differences between three plots (grass, tree and shrub) were analysed and formed the input base for stream bank stability modeling. We did not find particular differences between the grass and shrub plot but we did observe a significantly lower soil moisture content, lower soil porosity and higher shear strength within the tree plot. All three plots were stable during the monitoring period, however modeling scenarios made it possible to analyse potential differences in stream bank stability under different vegetation cover depending on root reinforcement and slope angle.

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Sammendrag

Soils are vital for supporting food security and other ecosystem services. Climate change can affect soil functions both directly and indirectly. Direct effects include temperature, precipitation, and moisture regime changes. Indirect effects include those that are induced by adaptations such as irrigation, crop rotation changes, and tillage practices. Although extensive knowledge is available on the direct effects, an understanding of the indirect effects of agricultural adaptation options is less complete. A review of 20 agricultural adaptation case‐studies across Europe was conducted to assess implications to soil threats and soil functions and the link to the Sustainable Development Goals (SDGs). The major findings are as follows: (a) adaptation options reflect local conditions; (b) reduced soil erosion threats and increased soil organic carbon are expected, although compaction may increase in some areas; (c) most adaptation options are anticipated to improve the soil functions of food and biomass production, soil organic carbon storage, and storing, filtering, transforming, and recycling capacities, whereas possible implications for soil biodiversity are largely unknown; and (d) the linkage between soil functions and the SDGs implies improvements to SDG 2 (achieving food security and promoting sustainable agriculture) and SDG 13 (taking action on climate change), whereas the relationship to SDG 15 (using terrestrial ecosystems sustainably) is largely unknown. The conclusion is drawn that agricultural adaptation options, even when focused on increasing yields, have the potential to outweigh the negative direct effects of climate change on soil degradation in many European regions.

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Sammendrag

This study presents a specifically designed Mercury module in a coupled benthic-pelagic reactive-transport model - Bottom RedOx Model (BROM) that allows to study mercury (Hg) biogeochemistry under different conditions. This module considers the transformation of elemental mercury (Hg(0)), divalent mercury (Hg(II)) and methylmercury (MeHg). The behavior of mercury species in the model is interconnected with changes of oxygen, hydrogen sulfide, iron oxides, organic matter, and biota. We simulated the transformation and transport of Hg species in the water column and upper sediment layer under five different scenarios, combining various levels of oxygenation and trophic state in the Berre lagoon, a shallow eutrophic lagoon of the French Mediterranean coast subjected to seasonal anoxia. The first scenario represents the conditions in the lagoon that are compared with experimental data. The four other scenarios were produced by varying the biological productivity, using low and high nutrient (N and P) concentrations, and by varying the redox conditions using different intensity of vertical mixing in the water column. The results of the simulation show that both oxidized and reduced sediments can accumulate Hg, but any shifts in redox conditions in bottom water and upper sediment layer lead to the release of Hg species into the water column. Eutrophication and/or restricted vertical mixing lead to reducing conditions and intensify MeHg formation in the sediment with periodic release to the water column. Oxygenation of an anoxic water body can lead to the appearance of Hg species in the water column and uptake by organisms, whereby Hg may enter into the food web. The comparison of studied scenarios shows that a well-oxygenated eutrophic system favors the conditions for Hg species bioaccumulation with a potential adverse effect on the ecosystem. The research is relevant to the UN Minimata convention, EU policies on water, environmental quality standards and Mercury in particular.

Sammendrag

Mørdre nedbørfelt er en del av Program for jord- og vannovervåking i landbruket (JOVA) som rapporterer årlig om jordbruksdrift, avrenning og tap av partikler, næringsstoffer og plantevernmidler. I perioden fra 2010 til 2016 ble det observert de høye tap av fosfor i Mørdre-feltet. Denne rapporten presenterer en analyse av en lang tidsserie av observerte data for avrenning, suspendert sediment og fosfor tap som tar sikte på å undersøke årsakene til høye fosfortap samt eventuelt identifisere en permanent endring. Utfordringen er: (1) tidsavhengighet, (2) sammenkobling mellom prosessene i nedbørfelt og (3) nøyaktig informasjon om all aktiviteter i nedbørfeltet. Disse kan ikke identifiseres direkte fra gjeldende datasett. Forfattere identifiserte komplementære målinger og / eller tiltak som tar sikte på å undersøke og forstå vannets veier og transportprosesser for sediment og næringsstoffer i nedbørfeltet, og omfatter undersøkelser koblet til ekstreme hendelser.