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Production of biochar from corn cob and corn stalk has gained great interest for efficient waste management with benefits of improving soil properties, increasing crop productivity, and contributing to carbon sequestration. This study investigated slow pyrolysis of corn cob and corn stalk at 600 °C to characterize yields and properties of products, with focus on solid biochar. Spruce wood, a rather well studied woody biomass, was also included for comparison purposes. It was observed that yields of biochar and condensates from corn cob, corn stalk, and spruce wood were comparable. However, gas release profiles and yields from the three biomasses were quite different, which is mainly related to the different chemical compositions (i.e., hemicellulose, cellulose, lignin, and inorganic species) of the studied raw feedstocks. The produced biochars were analyzed for proximate analysis, CHNS-elemental analysis, specific surface area and specific pore volume for pores in the nm-range, inorganic composition, solid functional groups, and aromaticity. The corn cob and corn stalk biochar presented significantly higher concentration of inorganic elements, especially P and K, favoring soil application. The SEM analysis results showed that the spruce wood biochar has different microstructure than corn cob and corn stalk biochars. Condensates and light gases, as by-products from biochar production, contained over 50% of the energy and 40% of the total carbon of the initial biomass. Utilization of the condensates and light gases as valuable resources is therefore critical for improving environmental and energy benefits of the biochar production process.

Sammendrag

Deliverable 2.12. This report presents a picture of the inventory of the different models accounting and monitoring soil quality and soil carbon stocks used in 21 different countries in Europe, and especially for the reporting of greenhouse gas (GHG) emissions to the UNFCCC (UNFCCC, 2020). The report synthesizes the information collected regarding the use of these models both at national and farm scale, as well as information of other models for soil quality monitoring, by different actors (policy making, farmers, and extension services). The study identified a big variability in the models used at national level and GHG reporting, where the Yasso07 model is currently the most widely used, and with several countries planning its implementation in the future. The number of models used at the farm scale to estimate SOC change presented an even bigger variability than those reported at the national scale, including some of the models included in the national scale, but also incorporating smaller spatial models intended for use at the farm scale, at the field scale or even at smaller scales. Most of the models are intended for mineral soils, both arable or grasslands, and only a few are reported for organic soils and/or other land use. A big heterogeneity was also present in the reported soil quality models (besides those used for accounting for SOC change). Two models included in the national and farm scale are also included here (RothC and Yasso07). The most reported soil quality models focus on greenhouse gas (GHG) emissions estimation and leaching, and are mainly related to the nitrogen cycle, but also to other nutrients, and soil physical properties. Our results show that synergies derived from European collaborations are not fully used but offer the possibility to enhance the quality of model applications for national GHG reporting and at smaller scales for the support of farm management.

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Perennial versus short term (<3 years) grass vegetation cover is likely to have considerable differences in root density and thus carbon (C) inputs to soil. Carbon inputs are important to maintain soil organic carbon (SOC) and may even increase it. In Norway and Scandinavia, the SOC content in soil is often higher than in other parts of Europe, due to the cold climate and high precipitation (i.e. slower turnover rates for soil organic matter) and a dominance of animal production systems with a large amount of grassland. Here we aimed to evaluate differences in SOC content, down to 60 cm depth, of a long-term grassland (without ploughing for decades) and a short-term grassland (frequently renewed by ploughing) under contrasting climate, soil and management conditions. Quantification of SOC was carried out on three long-term experimental sites on an extended latitude gradient in West and North Norway. The samples were taken from 4 depth increments (0-5, 5-20, 20-40 and 40-60 cm) in treatments that have not been ploughed for at least 43 years, and in treatments that were ploughed every third year until 2011. Preliminary results suggest that there is no significant difference in SOC storage down to 60 cm between long-term and short-term grasslands.

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Background: Global warming is going to affect both agricultural production and carbon storage in soil worldwide. Given the complexity of the soil-plant-atmosphere continuum, in situ experiments of climate warming are necessary to predict responses of plants and emissions of greenhouse gases (GHG) from soils. Arrays of infrared (IR) heaters have been successfully applied in temperate and tropical agro-ecosystems to produce uniform and large increases in canopy surface temperature across research plots. Because this method had not yet been tested in the Arctic where consequences of global warming on GHG emission are expected to be largest, the objective of this work was to test hexagonal arrays of IR heaters to simulate a homogenous 3 °C warming of the surface, i.e. canopy and visible bare soil, of five 10.5-m2 plots in an Arctic meadow of northern Norway. Results: Our results show that the IR warming setup was able to simulate quite accurately the target + 3 °C, thereby enabling us to simulate the extension of the growing season. Meadow yield increased under warming but only through the lengthening of the growing season. Our research also suggests that, when investigating agricultural systems on the Arctic, it is important to start the warming after the vegetation is established,. Indeed, differential emergence of meadow plants impaired the homogeneity of the warming with patches of bare soil being up to 9.5 °C warmer than patches of vegetation. This created a pattern of soil crusting, which further induced spatial heterogeneity of the vegetation. However, in the Arctic these conditions are rather rare as the soil exposed by snow melt is often covered by a layer of senescent vegetation which shelters the soil from direct radiation. Conclusions: Consistent continuous warming can be obtained on average with IR systems in an Arctic meadow, but homogenous spatial distribution requires that the warming must start after canopy closure.

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The application of biochar to soils is a promising technique for increasing soil organic C and offsetting GHG emissions. However, large-scale adoption by farmers will likely require the proof of its utility to improve plant growth and soil quality. In this context, we conducted a four-year field experiment between October 2010 to October 2014 on a fertile silty clay loam Albeluvisol in Norway to assess the impact of biochar on soil physical properties, soil microbial biomass, and oat and barley yield. The following treatments were included: Control (soil), miscanthus biochar 8 t C ha1 (BC8), miscanthus straw feedstock 8 t C ha1 (MC8), and miscanthus biochar 25 t C ha1 (BC25). Average volumetric water content at field capacity was significantly higher in BC25 when compared to the control due to changes in BD and total porosity. The biochar amendment had no effect on soil aggregate (2–6 mm) stability, pore size distribution, penetration resistance, soil microbial biomass C and N, and basal respiration. Biochar did not alter crop yields of oat and barley during the four growing seasons. In order to realize biochar’s climate mitigation potential, we suggest future research and development efforts should focus on improving the agronomic utility of biochar in engineered fertilizer and soil amendment products.

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Precise methods for the detection of geologically stored CO2within and above soil surfaces are an impor-tant component of the development of carbon capture and storage (CCS) under terrestrial environments.Although CO2leaks are not expected in well-chosen and operated storage sites, monitoring is required bylegislation and any leakage needs to be quantified under the EU Emissions Trading Directive. The objec-tive of the present research was to test if13C stable isotope motoring of soil and canopy atmosphere CO2increases our detection sensitivity for CCS-CO2as compared with concentration monitoring only. A CO2injection experiment was designed to create a horizontal CO2gradient across 6 m × 3 m plots, which weresown with oats in 2011 and 2012. Injected CO2was methane derived and had an isotopic signature of−46.2‰. The CO2concentrations were measured within the soil profile with passive samplers and at sev-eral heights within the crop canopies. The CO2fluxes and their13C signatures were also measured acrossthe experimental plots. In situ monitoring and gas samples measurements were conducted with a cavityring down spectrometer (CRDS). The plots displayed hot spots of injected-CO2leakage clearly detectableby either concentration or isotopic signature measurements. In addition, the13C signature measurementsallow us to detect injected CO2in plot regions where its presence could not be unequivocally ascertainedbased on concentration measurement alone.

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Glyfosat er det mest brukte ugrasmiddelet i Norge. I 2003 ble det omsatt over 200 tonn glyfosat her til lands og bruken er økende. Glyfosat brukes hovedsakelig mot løvtrær i skogbruket og mot kveke i kornåkeren etter innhøsting. Tradisjonelt har glyfosat blitt regnet som lite miljøskadelig sammenlignet med andre sprøytemidler, fordi det brytes raskt ned og fordi det binder seg hardt til jordpartiklene. En har hatt den oppfatning at glyfosat ikke havner i vassdragene. I takt med utviklingen av bedre analysemetoder, har glyfosat de senere årene blitt påvist i grunnvannet i flere europeiske land (Tyskland, Wales, Spania, Hellas og Danmark). Danmark henter 99% av drikkevannet sitt fra grunnvann og har nå innført forbud mot sprøyting med glyfosat på leirjord i soner nær vassdrag og risikoutsatte områder. I Norge bruker vi nesten bare overflatevann som drikkevann. Statens næringsmiddeltilsyn initierte i 1997 en undersøkelse av overflatevann som benyttes til drikkevann i Norge. Lave konsentrasjoner av glyfosat og AMPA ble da påvist i 6 drikkevannskilder (Fonahn 2002). Glyfosat er altså mer mobilt enn man hittil har trodd. I prosjektet "Plantevernmidler i miljøet - Strategisk instituttprogram for redusert miljøbelastning ved bruk av plantevernmidler" har vi undersøkt hvordan klimaet påvirker nedbrytning og transport av glyfosat her til lands. Feltforsøk med glyfosat har blitt utført på to felt: Grue i Hedmark og Målselv i Troms. Resultatene fra disse feltforsøkene hjelper oss å avdekke hvilke mekanismer som styrer skjebnen til glyfosat i norsk jord.