Erik J. Joner
Head of Department/Head of Research
Biography
Abstract
Heavy metals in soil pose a constant risk for animals and humans when entering their food chains, and limited means are available to reduce plant accumulation from more or less polluted soils. Biochar, which is made by pyrolysis of organic residues and sees increasing use as a soil amendment to mitigate anthropogenic C emissions and improve agronomic soil properties, has also been shown to reduce plant availability of heavy metals in soils. The cause for the reduction of metal uptake in plants when grown in soils enriched with biochar has generally been researched in terms of increased pH and alkalinity, while other potential mechanisms have been less studied. We conducted a pot experiment with barley using three soils differing in metal content and amended or not with 2% biochar made from Miscanthus x giganteus, and assessed plant contents and changes in bioavailability in bulk and rhizosphere soil by measuring extractability in acetic acid or ammonium nitrate. In spite of negligible pH changes upon biochar amendment, the results showed that biochar reduced extractability of Cu, Pb and Zn, but not of Cd. Rhizosphere soil contained more easily extractable Cu, Pb and Zn than bulk soil, while for Cd it did not. Generally, reduced plant uptake due to biochar was reflected in the amounts of metals extractable with ammonium nitrate, but not acetic acid.
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.
Authors
Nanna B. Svenningsen Stephanie J Watts-Williams Erik J. Joner Fabio Battini Aikaterini Efthymiou Carla Cruz-Paredes Ole Nybroe Iver JakobsenAbstract
Arbuscular mycorrhizal fungi (AMF) colonise roots of most plants; their extra-radical mycelium (ERM) extends into the soil and acquires nutrients for the plant. The ERM coexists with soil microbial communities and it is unresolved whether these communities stimulate or suppress the ERM activity. This work studied the prevalence of suppressed ERM activity and identified main components behind the suppression. ERM activity was determined by quantifying ERM-mediated P uptake from radioisotope-labelled unsterile soil into plants, and compared to soil physicochemical characteristics and soil microbiome composition. ERM activity varied considerably and was greatly suppressed in 4 of 21 soils. Suppression was mitigated by soil pasteurisation and had a dominating biotic component. AMF-suppressive soils had high abundances of Acidobacteria, and other bacterial taxa being putative fungal antagonists. Suppression was also associated with low soil pH, but this effect was likely indirect, as the relative abundance of, e.g., Acidobacteria decreased after liming. Suppression could not be transferred by adding small amounts of suppressive soil to conducive soil, and thus appeared to involve the common action of several taxa. The presence of AMF antagonists resembles the phenomenon of disease-suppressive soils and implies that ecosystem services of AMF will depend strongly on the specific soil microbiome.
Authors
Alice Budai Daniel Rasse Thomas Cottis Erik J. Joner Vegard Martinsen Adam O'Toole Hugh Riley Synnøve Rivedal Ievina Sturite Gunnhild Søgaard Simon Weldon Samson ØpstadAbstract
Carbon content is a key property of soils with importance for all ecosystem functions. Measures to increase soil carbon storage are suggested with the aim to compensate for agricultural emissions. In Norway, where soils have relatively high carbon content because of the cold climate, adapting management practices that prevent the loss of carbon to the atmosphere in response to climate change is also important. This work presents an overview of the potential for carbon sequestration in Norway from a wide range of agricultural management practices and provides recommendations based on certainty in the reported potential, availability of the technology, and likelihood for implementation by farmers. In light of the high priority assigned to increased food production and degree of self-sufficiency in Norway, the following measures were considered: (1) utilization of organic resources, (2) use of biochar, (3) crop diversification and the use of cover crops, (4) use of plants with larger and deeper root systems, (5) improved management of meadows, (6) adaptive grazing of productive grasslands (7) managing grazing in extensive grasslands, (8) altered tillage practices, and (9) inversion of cultivated peat with mineral soil. From the options assessed, the use of cover crops scored well on all criteria evaluated, with a higher sequestration potential than previously estimated (0.2 Mt CO2-equivalents annually). Biochar has the largest potential in Norway (0.9 Mt CO2-equivalents annually, corresponding to 20% of Norwegian agricultural emissions and 2% of total national emissions), but its readiness level is not yet achieved despite interest from industry to apply this technology at large scale. Extensive grazing and the use of deep-rooted plants also have the potential for increasing carbon storage, but there is uncertainty regarding their implementation and the quantification of effects from adapting these measures. Based on the complexities of implementation and the expected impacts within a Norwegian context, promising options with substantial payoff are few. This work sheds light on the knowledge gaps remaining before the presented measures can be implemented.
Authors
Paal Krokene Beatrix Alsanius Jorunn Børve Daniel Flø Bjørn Arild Hatteland Erik J. Joner Lawrence Richard Kirkendall Christer Magnusson Mogens Nicolaisen Line Nybakken Johan Stenberg Selamawit Tekle Gobena Kristine Bakke Westergaard Sandra A.I. WrightAbstract
Import av planter med jord og andre vekstmedier til Norge utgjør en betydelig risiko for innføring av planteskadegjørere som kan skade landbruket og naturlige økosystemer. Denne risikoen kan reduseres ved å stille strengere importkrav. Dette er hovedkonklusjonen i en risikovurdering Vitenskapskomiteen for mat og miljø (VKM) har gjort for Mattilsynet og Miljødirektoratet. Oppdragsgiverne har bedt VKM vurdere risikoen forbundet med jord og andre vekstmedier som følger med importerte planter. De har også bedt oss vurdere hvor effektive ulike risikoreduserende tiltak er for å forhindre innførsel av planteskadegjørere. Bakgrunn Planteskadegjørere som sopp, bakterier, nematoder og insekter kan komme til Norge med jord og andre vekstmedier som følger med importerte planter fra Europa. Slike skadegjørere kan forårsake alvorlig skade på norsk plantehelse. Selv med dagens kontrolltiltak, er det høy sannsynlighet for at skadelige organismer kan komme inn i landet. Risiko VKM har identifisert flere planteskadegjørere som er knyttet til import av jord og andre vekstmedier, og vurdert risikoen for negative effekter på norsk plantehelse: Planteskadegjørere i jord og vekstmedier: Jord og vekstmedier kan inneholde skadelige organismer som kan etablere og spre seg i Norge, noe som kan skade landbruket og økosystemer. Høye importvolumer av planter med jord og vekstmedier øker sannsynligheten for innføring av skadegjørere. Spesielt import fra land som Nederland, Tyskland, Danmark og Sverige medfører høy risiko, fordi mesteparten av plantene som importeres til Norge kommer fra disse landene. Nåværende regelverk og kontrolltiltak, som i stor grad baserer seg på visuell inspeksjon, er ikke tilstrekkelige for å oppdage alle skadegjørere. - Når vi kjøper levende planter, vokser de i et tilhørende vekstmedium. Denne klumpen rundt rota kan inneholde skadegjørere, som insekter, sopp, rundormer eller bakterier. Kanskje har planten levd mange år i dette vekstmediet før den kommer til Norge – det kan ha utviklet seg et helt lite økosystem nede i potten. Når vi importerer busker og trær er det dermed stor sannsynlighet for at de har med seg organismer vi ikke ønsker inn i landet. Disse organismene kan gjøre alvorlig skade på norsk plantehelse, og påvirke både landbruket og naturlige økosystemer, sier fagansvarlig Paal Krokene, som sitter i VKMs faggruppe for plantehelse, og har ledet arbeidet med rapporten. Risikoreduserende tiltak VKM er også bedt om å identifisere flere tiltak som kan redusere risikoen for uønsket innførsel av planteskadegjørere: Strengere krav til import av jord og andre vekstmedier, inkludert bruk av sterile eller varmebehandlete vekstmedier. Innføring av obligatorisk grensekontroll og mer omfattende inspeksjoner av planter importert med jord og vekstmedier. Forbud mot import av planter med jord og andre vekstmedier fra områder med kjent høy risiko for å huse planteskadegjørere. Bruk av DNA-analyser og andre avanserte metoder for å bedre påvise skadegjørere i vekstmedier, også i tilfeller der plantene ikke har synlige tegn på infeksjon. Konklusjon Import av planter med jord og andre vekstmedier utgjør en betydelig risiko for introduksjon av planteskadegjørere. Strengere kontrolltiltak og regelverk vil kunne bidra til å redusere risikoen for innførsel av skadelige organismer og beskytte norsk plantehelse.
Abstract
Since the 1950s, the use of plastics in agriculture has helped solving many challenges related to food production, while its persistence and mismanagement has led to the plastic pollution we face today. Soils are no exception and concentrations of polyethylene mulch debris up to 380 kg/ha have been reported in Chinese agricultural soils. A variety of biodegradable plastic products have thus been developed and marketed, with the aim to solve plastic pollution through complete degradation after use. But the environmental conditions for rapid and complete degradation are not always fulfilled, and the risk that biodegradable plastics could also contribute to plastic pollution must be evaluated. In this presentation, we want to share the knowledge gained through research projects on biodegradable plastics in agricultural soil, where we both studied the degradation of biodegradable mulch under Nordic soil conditions, and the fate of other biodegradable plastics in soil amendments such as compost and biogas digestate. A two-year field experiment with biodegradable mulch (PBAT-starch and PBAT-PLA) buried in soil in mesh bags showed that also under colder climatic conditions does degradation occur, involving fragmentation already after 2 months, but that complete degradation may take 3 to 9 years, depending on soil temperature and soil organic matter content (both correlate positively with degradation rate). Accumulation is therefore likely to happen when biodegradable mulch is repeatedly used every year. A full-scale experiment with compostable plastic cups (PLA) at an industrial composting plant, where we followed their fate and conducted metagenomic analysis over 13 weeks, demonstrated the major role played by fungi for a successful degradation of PLA. However, the successful management of biodegradable plastic products largely depends on existing waste management infrastructure. Most biodegradable plastic bags, labelled as compostable and used for food waste collection do not end up in industrial composting plants in Norway, but in biogas production plants. Here, we showed that these plastic bags (Mater-Bi®) are only marginally degraded (maximum 21-33 % mass loss) during biogas production, and likely to end up in biogas digestate and then in agricultural soils, unless digestate is treated to remove plastic residues.
Division of Environment and Natural Resources
PROLAND – Protecting agricultural lands from plastic pollution
PROLAND addresses the sources of plastic pollution in agricultural soils: sewage sludge, compost, biogas digestate, agricultural plastics, and atmospheric deposition. The project unfolds pressures of plastic and associated chemical hazards by analyzing their levels in soils and conducting fate and impact studies. It deploys cutting edge “design thinking” methods to co-develop measures for pollution prevention.
Division of Environment and Natural Resources
TerraNordica: Nordic Partnership for Soil Health and Agroecology
Soil health and Ecosystem Services (ES) are assessed through measuring carefully selected physical, chemical, and biological soil indicators related to dynamic soil properties, and compare these to thresholds or standard values that separate healthy from unhealthy conditions.