Marianne Stenrød
Director
Authors
Christophe Moni Eva Farkas Claire Coutris Hanna Marika Silvennoinen Anders Aas Marit Almvik Liang Wang Kathinka Lang Xingang Liu Marianne StenrødAbstract
Biochar and pesticides are likely to be increasingly used in combination in agricultural soils, yet their combined effects on climate change mitigation remain unexplored. This study presents an 8-month incubation experiment with different soil types (silt loam and sandy loam), biochars (corncob and corn stem), and pesticides (with and without a pesticide mixture), during which CO2 production from soil organic matter (SOM) and biochar mineralisation was monitored using isotopic methods. A comprehensive modelling approach, describing all mineralisation results over the entire incubation with a reduced set of parameters, was employed to isolate the effects of biochar, pesticides, and their interactions across soil types and carbon pools, and captured the dynamic effect of biochar on SOM mineralisation. Over 99.5% of biochars remained inert after 8 months, confirming the role of biochar as a carbon sequestration technology. Biochar addition showed higher SOM stabilisation potential in soil with high clay content compared to soil with low clay content. This suggests that biochar amendment should be considered carefully in clay-depleted soils, as it could result in a loss of native SOM. Corn stem biochar, characterised by high surface area and low C/N ratio, demonstrated higher SOM stabilisation potential than corncob biochar with low surface area and high C/N ratio. Pesticide application reduced SOM mineralisation by 10% regardless of soil and biochar types. Finally, the interaction between corncob biochar and pesticides further reduced SOM mineralisation by 5%, while no interactive effect was observed with corn stem biochar. These findings highlight the importance of considering biochar-pesticide interactions when evaluating the impact of biochar amendments on native SOM stability.
Authors
Live Lingaas Nesse Kristin Forfang Jannice Schau Slettemeås Snorre Hagen Marianne Sunde Abdelhameed Elameen Gro Skøien Johannessen Marianne Stenrød Girum Tadesse Tessema Marit Almvik Hans Geir EikenAbstract
The abundance and diversity of antimicrobial-resistant bacteria (ARB) and antimicrobial resistance genes (ARGs) in agricultural landscapes may be important for the spread of antimicrobial resistance (AMR) in the environment. The aim of this study was to apply screening methods for ARB and ARGs to investigate the impact of farming on the prevalence of AMR in a country with low antibiotic usage. We have analyzed samples (n = 644) from soil and wild terrestrial animals and plants (slugs, snails, mice, shrews, earthworms, and red clover) collected over two years in agricultural fields accompanied by nearby control areas with low human activity. All samples were investigated for the occurrence of 35 different ARGs using high-throughput quantitative PCR (HT-qPCR) on a newly developed DNA array. In addition, samples from the first year (n = 415) were investigated with a culture-based approach combined with whole-genome sequencing (WGS) to identify antimicrobial-resistant E. coli (AREC). ARGs were detected in 59.5% of all samples (2019 + 2020). AREC, which was only investigated in the 2019 samples, was identified in 1.9% of these. Samples collected in the autumn showed more ARGs and AREC than spring samples, and this was more pronounced for organic fields than for conventional fields. Control areas with low human activity showed lower levels of ARGs and a lack of AREC. The use of livestock manure was correlated with a higher level of ARG load than other farming practices. None of the soil samples contained antibiotics, and no association was found between AMR and the levels of metals or pesticides. High qualitative similarity between HT-qPCR and WGS, together with the positive controls to the validation of our 35 ARG assays, show that the microfluid DNA array may be an efficient screening tool on environmental samples. In conclusion, even in a country with a very low consumption of antimicrobials by production animals, our results support the hypothesis of these animals being a source of AREC and ARGs in agricultural environments, primarily through the use of manure.
Authors
Marianne Stenrød Esther Bloem Nana Yaa Boahene Tor Fredrik Holth Tim Hofer Mette Helen Bjørge Müller Elise Rundén-Pran Christian VogelsangAbstract
Vitenskapskomiteen for mat og miljø (VKM) har oppdatert et metodedokument for helse og miljørisikovurderinger av plantevernmidler. Målet med oppdateringen er å gjenspeile gjeldende regelverk og praksis, og sikre kvaliteten på fremtidige risikovurderinger utført av faggruppen for plantevernmidler i VKM. Det forrige metodedokumentet er fra 2012, og oppdateringen var nødvendig for å tilpasse metodene til nytt EU-regelverk for plantevernmidler, og for å innarbeide nye datakrav og retningslinjer for plantevernmidler og biocider. Ved å oppdatere metodedokumentet, ønsket faggruppen å sikre at risikovurderingene de leverer er i tråd med gjeldende regelverket og vitenskapelig kunnskap. Viktige endringer Dokumentet er oppdatert med henvisninger til nye forskrifter og veiledninger, om for eksempel biocider, nye typer plantevernmidler, og forenklet godkjenning/risikovurdering for mikrobielle stoffer. Det nye dokumentet inneholder også veiledning om fareidentifikasjon av stoffer med hormonforstyrrende egenskaper, alternative metoder for å redusere toksikologisk testing hos dyr, og vurdering av ikke-kostholdeksponering av plantevernmidler. Dokumentet inneholder oppdatert informasjon om metodikk knyttet til vurdering av plantevernmidlers egenskaper og skjebne i miljøet, inkludert norske jord- og klimaforhold, renseanlegg og drikkevannsrenseprosesser. Veiledning om risikovurdering for bier og andre insekter, akvatiske organismer, fugler, pattedyr og andre vertebrater, samt meitemark og andre jordlevende organismer, er også oppdatert. Innen flere av feltene er eller vil det bli etablert spesifikke beskyttelsesmål og trinnvise risikovurderinger. Samlet sett fungerer det oppdaterte metodedokumentet som en referanse for VKMs risikovurderingsarbeid for plantevernmidler, og sikrer at fremtidige vurderinger gjennomføres i samsvar med gjeldende regelverk og vitenskapelig kunnskap. Metode VKM har benyttet en semi-systematisk tilnærming, ved å utarbeide et arbeidsdokument for innhenting og sammenstilling av nødvendig informasjon om nye datakrav fra gjeldende regelverk for plantevernmidler og biocider i EU. Dokumentet er godkjent av VKMs faggruppe for plantevernmidler.