Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
2026
Sammendrag
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Forfattere
Junbin Zhao Mounir Takriti Per-Erik Jansson Ed Jones Mikhail Mastepanov Erling Fjelldal Cornelya Klutsch David Kniha Runar Kjær Simon Weldon Kjetil Fadnes Knut Bjørkelo Jonathan Rizzi Christian Wilhelm Mohr Gunnhild Søgaard Jagadeesh YeluripatiSammendrag
Abstract Peatlands drained for agriculture and other uses release substantial carbon dioxide. Many countries estimate these emissions using the 2014 IPCC Tier 1 emission factors. Here we calibrated an ecosystem model with data from two cultivated peatland sites in Norway and simulate carbon dioxide emissions at 50 sites nationwide for 2001–2022. Model results showed that carbon dioxide emissions were strongly controlled by water table depth and aligned well with observations from other European peatlands of similar climate zones. Crucially, the Tier 1 emission factor matched our simulations only under very deep water tables (< –0.7 m), but overestimated emissions by 31–88% when water levels ranged from –0.7 m to –0.3 m. This indicates that Tier 1 methods may overstate emissions from cultivated peatlands in cool temperate and boreal regions, inflating estimates of mitigation potential. Tier 2 or 3 approaches can reduce uncertainty but require more field data.
Forfattere
Junbin ZhaoSammendrag
Det er ikke registrert sammendrag
Sammendrag
Sustainable agricultural practices are needed to ensure food production and minimize environmental impacts. In high-latitude regions, where the potential for agricultural production is increasing due to rising temperatures and prolonged growing seasons, undersowing cover crops and the application of biochar are promising methods. However, current understanding of the simultaneous uptake of multiple essential nutrients into the cover crop biomass, and the effects of cover crops and biochar on the main crop’s physiology, remains limited. This study was conducted in a field experiment in Mid-Norway, five years after its establishment. We compared six treatments: unfertilized oats (Control); NPK-fertilized oats with and without biochar (Biochar and Monocrop); and three NPK-fertilized cover crop systems where oats were undersown with ryegrass (hereafter referred to as “Ryegrass”); ryegrass, red clover, and white clover (hereafter referred to as “Clover”); and ryegrass, red clover, bird’s-foot trefoil, and chicory (hereafter referred to as “Chicory”). At different stages during the growing season, shoot and root samples of oats and cover crops were analyzed for biomass and essential nutrients, oat gas exchange was measured, and soil plant-available nitrogen and the soil’s C/N ratio were determined. Cover crop mixtures showed 2.4 to 13.7-fold higher uptake of N, Ca, Mg, B, and Cu in their shoots and 2.9 to 4.6-fold higher uptake of N and B in their roots compared to the Ryegrass system. The cover crop roots accounted for approximately 20-45% of the total nutrient uptake for most nutrients. During tillering, the cover crops increased the concentration of plant-available nitrogen in the soil, thereby compensating for the competition from cover crops in the system. Undersowing cover crops had no significant effect on oat plant biomass, gas exchange, yield, or nutrient concentrations in oat tissue. Only oats in the Ryegrass system showed a lower root biomass and dark respiration during tillering and decreased nutrient uptake in the oat biomass during tillering and grain filling, without affecting yield. Biochar application significantly reduced the concentrations of N, K, Ca, Mg, S, Na, and Cu in oat shoots (13-61%) and N in oat roots (15%) during tillering. Although these deficiencies were compensated for by grain filling and no effect of biochar on the grain yield was observed, the grain protein content remained reduced. The results highlight the importance of cover crop mixtures and nutrient storage in cover crop roots for nutrient legacy effects in high-latitude agriculture and demonstrate the need for optimized biochar management to avoid temporary nutrient shortages and maintain yield quality.
Forfattere
Steffen A. Schweizer Yahan Hu Johann Maximilian Zollner Thiago Inagaki Carmen Höschen Martin WernerSammendrag
Mineral-associated organic matter (OM) exhibits a heterogeneous arrangement in soils at the microscale and nanoscale as revealed by high-resolution imaging techniques. The arrangement of OM at the microscale has broad implications for biogeochemical cycles of major elements such as C and N by compartmentalizing their dynamics into distinct micropatches and a few µm-sized hotspots. It is crucial to understand the organization of this heterogeneous microscale arrangement across diverse soil systems. Here, we present a meta-analysis of spatial patterns of OM patches based on unsupervised segmentation of nanoscale secondary ion mass spectrometry (NanoSIMS) measurements. Using a dataset of over 450 measurements of fine fractions from soils with different texture and C content, we evaluated the spatial coverage, clustering, and heterogeneity of OM micropatches across mineral surfaces. The OM coverage across mineral surfaces linearly correlated with the bulk soil C content, indicating a spatially expanding arrangement of OM whereas large parts of mineral-dominated surface remain. Higher OM coverage was related to more connected and more clustered OM patches. Within the OM patches, we found evidence of recurring µm-sized distinct C-rich and N-rich subunits based on a fractal geography approach. Within more homogeneous OM patches, subunits showed stronger differentiation in C and N composition, whereas subunits within more heterogeneous patches exhibited less differentiated C and N composition. The distinct spatial organization of OM micropatches observed here suggests a compartmentalized framework of OM dynamics with implications for C and N cycling in soils.
Forfattere
Raphael Silva Thiago Inagaki Thomas Trentin Laura Péres Cléber Jesus Luis Alleoni Matheus SoaresSammendrag
Highly reactive, fine-particle biochars are particularly effective in recarbonizing degraded soils, but they can be more vulnerable to fire degradation due to higher surface area. How biochar particle size influences its persistence in the environment remains poorly understood, particularly in regions affected by fire events such as the Cerrado. In this study, we investigated the stability of micrometric (200 µm) and nanometric (<50 nm) açaí seed biochar incubated in an Oxisol for 180 days, followed by simulated burning using a propane–butane torch. Biochar amended soil had higher total C and nitrogen (N) contents, with a 43% increase for microbiochar and 88% for nanobiochar in the mineral-associated organic matter (MAOM) fraction, indicating incorporation into stable pools. Burning reduced C associated with the particulate organic matter (POM) more when amended with microbiochar than with nanobiochar, demonstrating their vulnerability fire. An increase, up to fivefold, in dissolved organic carbon (DOC) and nitrogen (DN) contents occurred after burning. XRD data showed no mineralogical differences among samples, while FTIR indicated loss of polysaccharides after burning. TGA revealed that microbiochar was more thermally stable under unburned conditions but lost stability after burning. In contrast, nanobiochar was less stable in unburned soil but became more stable following burning, resulting in lower mass loss. The reduced mass loss in the burned control is attributed to its ~40% lower soil C content. Biochar’s particle size governs carbon stability, fire vulnerability, and post-burn soil resilience, thereby using nanobiochar for fire-prone areas act as strategy improving the management of agricultural soils.
Forfattere
Thiago Inagaki Junbin Zhao Claire Douheret Pierre-Adrien Rivier Jihong Liu Clarke Nicholas ClarkeSammendrag
Earthworms enhance compost mineralization, improving its fertilizer value and soil quality (biological activity, structure). However, they often increase greenhouse gas (GHG) emissions, particularly nitrous oxide (N₂O), via nitrogen mineralization. Combining biochar with compost may mitigate these emissions while further boosting soil benefits alongside earthworm activity. We present preliminary results from a soil incubation (2 months) experiment testing this synergy. Using a Norwegian loam Cambisol, a 2x2x2 factorial design (four replicates) assessed the presence/absence of earthworms (Lumbricus terrestris - 10 adults/jar), compost (manure/food waste - 60 Mg ha⁻¹ equivalent), and rice-straw biochar (700°C pyrolyzed - 20 Mg ha⁻¹ equivalent). We hypothesized that earthworm and compost addition may present synergistic effects in improving N mineralization with consequent enhanced GHG emissions. We expect that biochar may counteract these emissions and potentially present positive effects for soil quality. The goal was to develop a biochar-compost-earthworm system creating a fertilizer with higher nutrient availability and lower GHG emissions. In the first week of the incubation, we found that higher CO2 and N2O productions were associated with the presence of compost. Earthworms could further enhance the carbon decomposition but appeared to mitigate CH4 production. Further analysis will be carried out with a focus on GHG emissions (CO₂, CH₄, N₂O) and nitrogen mineralization dynamics.
Forfattere
Thiago Inagaki Frederik Bøe Ievina Sturite Meike S. Bärmann Franziska Bucka Alice Budai Anders Aas Daniel RasseSammendrag
In high-latitude arable systems (63.9°N), short growing seasons and cold climates often constrain regenerative practices. This study investigates how cover crop (CC) diversity influences the synergy among root development, carbon (C) persistence, and nutrient (N and P) dynamics within a barley (Hordeum vulgare L.)-oat (Avena sativa) rotation. Over three years, we evaluated a gradient of CC intercropping complexity using a randomized complete block design. Treatments were: (1) Control (barley/oat without NPK), (2) Biochar-Fertilizer (barley/oat + NPK + 1.8 Mg ha-1 year-1 biochar), (3) Monocrop (barley/oat), (4) Ryegrass (barley + ryegrass), (5) Clover (barley + ryegrass + white/red clover), and (6) Chicory (barley + ryegrass + red clover + chicory + bird’s-foot trefoil). We quantified root biomass, soil organic matter (SOM) fractions, specifically Mineral-Associated Organic Matter (MAOM) and Particulate Organic Matter (POM), aggregate stability, nutrient stocks, and microbial abundance via qPCR. The CCs sown shortly after barley were successfully established, with an average biomass of 1525 kg/ha, without compromising cereal yields, thereby confirming their viability in Nordic climates. A central finding was that root development served as the primary driver of organo-mineral associations. Ryegrass- and Clover-based systems produced significantly higher root biomass, which correlated strongly (p < 0.01) with MAOM stocks and total P acquisition. These systems stored 12 Mg/ha more MAOM-C and 1.1 Mg/ha more MAOM-N than the control at 0-20 cm depth. The inclusion of diverse functional traits in the complex five-species mixture significantly improved soil physical structure, yielding higher aggregate stability and lower bulk density. While CCs accumulated approximately 7 kg P/ha, the diverse mix optimized nutrient availability, whereas simpler mixtures showed higher C:P ratios, suggesting potential microbial P immobilization. Microbial abundance was consistently higher in multi-species treatments, indicating a more active biological environment. Ongoing analysis integrates cereal physiological data, focusing on the photosynthetic efficiency of oats in response to cultivation? regimes. Our findings bridge the gap between root morphology, plant physiology, and long-term SOM persistence, providing a strategic framework for using functional crop traits to enhance soil resilience and nutrient efficiency in cold-climate regions.
Forfattere
Thiago Inagaki Frederik Bøe Ievina Sturite Meike Sophie Bärmann Franziska Bucka Alice Budai Anders Aas Daniel RasseSammendrag
High-latitude regions pose challenges for soil organic matter (SOM) sequestration and for improving soil fertility due to low temperatures, which shorten growing seasons and promote off-season nutrient leaching. Even long-term experiments on conservation practices have shown only modest increases in C storage. Nonetheless, persistent SOM fractions, such as mineral-associated organic matter (MAOM), have been shown to improve relatively quickly through conservation practices in temperate regions, which could be key in high-latitude regions. MAOM is an important SOM fraction not only for promoting carbon (C) storage but also for providing an available form of nitrogen (N) for plant nutrition. In this study, we show that, in Norwegian agriculture (63.9°N), MAOM (C and N) stocks improved only after three years of implementing cover crop systems that combined 1 to 4 cover crops with cereals (barley or oats) intercropped simultaneously (12 Mg ha-1 for C and 1.1 Mg ha-1 for N in the 0-20 cm layer more compared to unfertilized Control plots). Cover crops containing red and white clover and ryegrass efficiently increased the MAOM fraction in soil. An increase in root biomass and changes in root morphology were the primary factors linking cover crops to MAOM improvements in this field. In addition to benefits for SOM stocks, we recorded improvements in microbial abundance, soil structure, nutrient cycling, and cereal physiology. Our findings help to reframe MAOM as a bioavailable nutrient pool essential for soil health and nutrient cycling, which can be improved in the relatively short term through root development.
Forfattere
Thiago InagakiSammendrag
Det er ikke registrert sammendrag