Daniel Rasse
Head of Department/Head of Research
Authors
Simon Weldon Bert van der Veen Eva Farkas Nazli Pelin Kocatürk Schumacher Alba Dieguez-Alonso Alice Budai Daniel RasseAbstract
Sorption of nutrients such as NH4+ is often quoted as a critical property of biochar, explaining its value as a soil amendment and a filter material. However, published values for NH4+ sorption to biochar vary by more than 3 orders of magnitude, without consensus as to the source of this variability. This lack of understanding greatly limits our ability to use quantitative sorption measurements towards product design. Here, our objective was to conduct a quantitative analysis of the sources of variability, and infer which biochar traits are more favourable to high sorption capacity. To do so, we conducted a standardized remodelling exercise of published batch sorption studies using Langmuir sorption isotherm. We excluded studies presenting datasets that either could not be reconciled with the standard Langmuir sorption isotherm or generated clear outliers. Our analysis indicates that the magnitude of sorption capacity of unmodified biochar for NH4+ is lower than previously reported, with a median of 4.2 mg NH4+ g−1 and a maximum reported sorption capacity of 22.8 mg NH4+ g−1. Activation resulted in a significant relative improvement in sorption capacity, but absolute improvements remain modest, with a maximum reported sorption of 27.56 mg NH4+ g−1 for an activated biochar. Methodology appeared to substantially impact sorption estimates, especially practices such as pH control of batch sorption solution and ash removal. Our results highlight some significant challenges in the quantification of NH4+ sorption by biochar and our curated data set provides a potentially valuable scale against which future estimates can be assessed.
Authors
Simon Weldon Bert van der Veen Eva Farkas Nazli Pelin Kocatürk Schumacher Alba Dieguez-Alonso Alice Budai Daniel RasseAbstract
Sorption of nutrients such as NH4+ is often quoted as a critical property of biochar, explaining its value as a soil amendment and a filter material. However, published values for NH4+ sorption to biochar vary by more than 3 orders of magnitude, without consensus as to the source of this variability. This lack of understanding greatly limits our ability to use quantitative sorption measurements towards product design. Here, our objective was to conduct a quantitative analysis of the sources of variability, and infer which biochar traits are more favourable to high sorption capacity. To do so, we conducted a standardized remodelling exercise of published batch sorption studies using Langmuir sorption isotherm. We excluded studies presenting datasets that either could not be reconciled with the standard Langmuir sorption isotherm or generated clear outliers. Our analysis indicates that the magnitude of sorption capacity of unmodified biochar for NH4+ is lower than previously reported, with a median of 4.2 mg NH4+ g−1 and a maximum reported sorption capacity of 22.8 mg NH4+ g−1. Activation resulted in a significant relative improvement in sorption capacity, but absolute improvements remain modest, with a maximum reported sorption of 27.56 mg NH4+ g−1 for an activated biochar. Methodology appeared to substantially impact sorption estimates, especially practices such as pH control of batch sorption solution and ash removal. Our results highlight some significant challenges in the quantification of NH4+ sorption by biochar and our curated data set provides a potentially valuable scale against which future estimates can be assessed.
Authors
Daniel RasseAbstract
No abstract has been registered
Authors
Daniel RasseAbstract
No abstract has been registered
Authors
Daniel Rasse Simon Weldon Erik J. Joner Stephen Joseph Claudia I. Kammann Xiaoyu Liu Adam O´Toole Genxing Pan Nazli Pelin Kocatürk SchumacherAbstract
Background Biochar-based fertilizer products (BCF) have been reported to increase both crop yield and N-use efficiency. Such positive effects are often assumed to result from the slow-release of N adsorbed on BCF structures. However, a careful review of the literature suggests that actual mechanisms remain uncertain, which hampers the development of efficient BCF products. Scope Here, we aim at reviewing BCF mechanisms responsible for enhanced N uptake by plants, and evaluate the potential for further improvement. We review the capacity of biochar structures to adsorb and release N forms, the biochar properties supporting this effect, and the methods that have been proposed to enhance this effect. Conclusions Current biochar products show insufficient sorption capacity for the retention of N forms to support the production of slow-release BCFs of high enough N concentration. Substantial slow-release effects appear to require conventional coating technology. Sorption capacity can be improved through activation and additives, but currently not to the extent needed for concentrated BCFs. Positive effects of commercial BCFs containing small amount of biochar appear to result from pyrolysis-derived biostimulants. Our review highlights three prospects for improving N retention: 1) sorption of NH3 gas on specifically activated biochar, 2) synergies between biochar and clay porosities, which might provide economical sorption enhancement, and 3) physical loading of solid N forms within biochar. Beyond proof of concept, quantitative nutrient studies are needed to ascertain that potential future BCFs deliver expected effects on both slow-release and N use efficiency.
Abstract
No abstract has been registered
Abstract
Communication to JordPro AS about the research status regarding the use of biochar as an ingredient in organic fertilizer products.
Abstract
Biochar-based fertilizer products (BCF) are receiving increasing attention as potential win-win solutions for mitigating climate change and improving agricultural production. BCFs are reported to increase yields through increased N use efficiency, an effect which is often assumed to result from the slow-release of adsorbed N forms into the soil. Here, we review the magnitude of this effect, the potential for further improvement and the need to consider other mechanisms in product development. Current high-N commercial BCFs are mostly physical blends of biochar and mineral fertilizer, with little evidence of slow-release effects supported by sorption mechanisms. For such products, the main effect potentially results from root-growth promoting factors and from increases in soil pH and Eh and stimulation of beneficial micro-organisms in the rhizosphere, which all result in an increase in uptake of specific nutrients. Our reanalysis of literature data indicates that the median sorption capacity of untreated biochar for mineral N forms requires applying 200 times more biochar than N fertilizer. This ratio needs reducing by at least an order of magnitude for producing efficient sorption-based BCFs. Activation of biochar with acids and oxidizing agents, as reported in many studies, appears to only marginally increase sorption capacity in absolute values. Fixation of clay and organics within the porous structure of biochar appears a more promising technology, suggesting that macro- and mesoporosity is a key biochar property that deserves greater scrutiny and research towards making efficient sorption-based BCFs. Mechanisms of action and dose responses need to be more systematically studied in order to devise products that combine positive effects and can be used within realistic agronomic management practices. Long-term effects resulting from accumulated annual inputs of BCF also need to be better evaluated in terms of nutrient cycling and the progressive improvement of soil health.
Authors
Liang Wang Alba Dieguez-Alonso Maria Nicte Polanco Olsen Simon Weldon Alice Budai Daniel Rasse Øyvind SkreibergAbstract
No abstract has been registered
Abstract
Forest harvest residue is a low-competitive biomass feedstock that is usually left to decay on site after forestry operations. Its removal and pyrolytic conversion to biochar is seen as an opportunity to reduce terrestrial CO2 emissions and mitigate climate change. The mitigation effect of biochar is, however, ultimately dependent on the availability of the biomass feedstock, thus CO2 removal of biochar needs to be assessed in relation to the capacity to supply biochar systems with biomass feedstocks over prolonged time scales, relevant for climate mitigation. In the present study we used an assembly of empirical models to forecast the effects of harvest residue removal on soil C storage and the technical capacity of biochar to mitigate national-scale emissions over the century, using Norway as a case study for boreal conditions. We estimate the mitigation potential to vary between 0.41 and 0.78 Tg CO2 equivalents yr−1, of which 79% could be attributed to increased soil C stock, and 21% to the coproduction of bioenergy. These values correspond to 9–17% of the emissions of the Norwegian agricultural sector and to 0.8–1.5% of the total national emission. This illustrates that deployment of biochar from forest harvest residues in countries with a large forestry sector, relative to economy and population size, is likely to have a relatively small contribution to national emission reduction targets but may have a large effect on agricultural emission and commitments. Strategies for biochar deployment need to consider that biochar's mitigation effect is limited by the feedstock supply which needs to be critically assessed.
Authors
Liang Wang Alba Dieguez-Alonso Maria Nicte Polanco Olsen Alice Budai Daniel Rasse Øyvind SkreibergAbstract
No abstract has been registered
Authors
Liang Wang Alba Dieguez-Alonso Maria Nicte Polanco Olsen Alice Budai Daniel Rasse Ondřej Mašek Øyvind SkreibergAbstract
No abstract has been registered
Authors
Alexandre Tisserant Marjorie Morales Otávio Cavalett Adam O´Toole Simon Weldon Daniel Rasse Francesco CherubiniAbstract
Limiting temperature rise below 2 °C requires large deployment of Negative Emission Technologies (NET) to capture and store atmospheric CO2. Compared to other types of NETs, biochar has emerged as a mature option to store carbon in soils while providing several co-benefits and limited trade-offs. Existing life-cycle assessment studies of biochar systems mostly focus on climate impacts from greenhouse gasses (GHGs), while other forcing agents, effects on soil emissions, other impact categories, and the implications of a large-scale national deployment are rarely jointly considered. Here, we consider all these aspects and quantify the environmental impacts of application to agricultural soils of biochar from forest residues available in Norway considering different scenarios (including mixing of biochar with synthetic fertilizers and bio-oil sequestration for long-term storage). All the biochar scenarios deliver negative emissions under a life-cycle perspective, ranging from -1.72 ± 0.45 tonnes CO2-eq. ha−1 yr−1 to -7.18 ± 0.67 tonnes CO2-eq. ha−1 yr−1 (when bio-oil is sequestered). Estimated negative emissions are robust to multiple climate metrics and a large range of uncertainties tested with a Monte-Carlo analysis. Co-benefits exist with crop yields, stratospheric ozone depletion and marine eutrophication, but potential trade-offs occur with tropospheric ozone formation, fine particulate formation, terrestrial acidification and ecotoxicity. At a national level, biochar has the potential to offset between 13% and 40% of the GHG emissions from the Norwegian agricultural sector. Overall, our study shows the importance of integrating emissions from the supply chain with those from agricultural soils to estimate mitigation potentials of biochar in specific regional contexts.
Authors
Miro Jacob Peter Maenhout Simone Verzandvoort Greet Ruysschaert Sigbert Huber Bettina Schwarzl Bruno Huygebaert Martin Hvarregaard Thorsøe Eloïse Mason Anna Jacobs Stella Sonnenburg Axel Don Lilian O’Sullivan David Wall Raimonds Kasparinskis Oļģerts Nikodemus Imants Kukuļs Ivo Vinogradovs Baiba Dirnēna Kristīne Afanasjeva Kristaps Auziņš Žydrė Kadžiulienė Frederik Bøe Jannes Stolte Kamilla Skaalsveen Teresa Gómez de la Bárcena Daniel Rasse Grzegorz Siebielec Fátima Calouro Ana Marta Paz Cristina Sempiterno Maria da Encarnação Marcelo Pedro Jordão Michal Sviček Kristína Buchová Vladimír Hutár Rok Mihelič Sara Mavsar Borut Vrščaj Klara Rekič Helena Grčman Benjamin Sanchez Lena Engström Noemi Peter Olivier Heller Gina Garland Peter Weisskopf Wieke Vervuurt Janjo de Haan Sevinc Madenoglu Hesna Ozcan Dario Fornara Elaine Groom Jill Mellon Suzanne Higgins Rachael Ramsey Alex Higgins Lisa BlackAbstract
Deliverable 2.5. This report contributes to the EJP SOIL roadmap for climate-smart sustainable agricultural soil management and research by identifying current policy targets and realizations and setting soil service aspirational goals by 2050 at the regional/national (Chapter 2) and European scale (Chapter 3). At both scales, the report is based on a desk study of current agricultural soil related policies, followed by a stakeholder consultation. Twenty countries/regions have contributed to the regional/national analyses and 347 different stakeholders have provided their views on soil policy. The policy analysis demonstrates that large differences exist between the number of policy targets per soil challenge. In general, the soil challenge ‘Maintaining/increasing soil organic carbon’ can be considered as the most important soil challenge taking into account both the policies of the participating countries and of the EU level. This soil challenge not only has (one of) the largest share(s) of quantitative and qualitative targets, but also has a large share of the targets for which an indicator and monitoring is in progress or existing. At the EU level, ‘Avoiding contamination’ is also particularly high addressed in policy documents. In the participating countries, other very important soil challenges in policy are ‘Enhance nutrient retention/use efficiency’, ‘Avoid soil erosion’ and ‘Avoid soil contamination’. These soil challenges comprise a large share of soil- and agricultural soil specific targets. However, despite the large number of policy targets, identified by the participating EJP SOIL countries, there is still a shared need for appropriate clear (quantified) policy targets with a specific time horizon, well-defined indicators and a monitoring systems. Similar results are found at the EU level. Policy targets addressing soil challenges are mostly not expressed in quantitative terms and indicators for monitoring policy targets with references to soil challenges were identified for less than half of the cases. From the stakeholder consultations, it becomes clear that for all soil challenges there is still a way to go before future aspirational goals will be met. Generally, when averaging between all countries, the gap between current policy targets and realizations is for most soil challenges considered between large and halfway in reaching the current policy targets and for most soil challenges current policy targets are regarded almost- to- far from being futureproof. In the prioritization of soil challenges, stakeholders at the regional/country and European level, clearly marked maintaining/increasing SOC as the most relevant soil challenge in the upcoming decades. The stakeholders explain the key role of maintaining/increasing soil organic carbon through the multiple interactions with other soil challenges and for climate change mitigation. At the EU level, the second highest ranked prioritization is soil sealing, due to its irreversible nature. This is, however, not reflected at the country level, potentially due to a misinterpretation of soil sealing as compaction by part of the stakeholders. At the country level, enhancing soil nutrient retention/use efficiency was ranked 2nd in the prioritization exercise. Generally, there is an urgency for policy updates, because the current policy is considered unable to tackle the prominent soil challenges. In the report, also the soil related management practices to achieve the aspirational goals have been identified, both in the policy analysis and in the stakeholder consultation. The most prominent differences between policy and stakeholders, is in the emphasis on the use of buffer strips and small landscape elements in policy, while measures in this category are less highly ranked by the stakeholders. On the other hand, conservation agriculture, agro-ecological farming, precision agriculture, incorporation ........
Authors
Leonor Rodrigues Julia Fohrafellner Brieuc Hardy Bruno Huyghebaert Jens Leifeld Alberto Sanz Cobeña Alice Budai Andis Lazdiņš Arezoo Taghizadeh Axel Don Bartosz Adamczyk Benjamin Gimeno Benjamin Sanchez Bo Stenberg Claudia Di Bene Corina Carranca Dalia Feiziene Daniel Rasse Daria Seitz Dario Fornara Eduardo Aguilera Elena Rodriguez Eloïse Mason Erich Inselsbacher Gabriela Barančíková Grzegorz Siebielec Heide Spiegel Imants Kukuļs Jacek Niedźwiecki Jan P. Lesschen Karin Kauer Kestutis Armolaitis Lilian OSullivan Lenka Pavlu Maarten De Boever Nils Kauer Peter Kuikman Peter Laszlo Raquel Mano Raimonds Kasparinskis Rok Mihelič Sevinc Madenoglu Sophie Cornu Sophie Zechmeister-Boltenstern Stephan Glatzel Sylvain Pellerin Teresa Gómez de la Bárcena Thalisa Slier Thomas Kätterer Martin A. Bolinder Kerstin Berglund Toth Toth GergelyAbstract
Deliverable 2.3. This synthesis identifies the available knowledge of achievable carbon sequestration in mineral soils and GHGs mitigation in organic soils in agricultural land, including pasture/grassland across Europe. The inventory of past and current studies on carbon sequestration and GHGs mitigation measures in agricultural soils and the methodology used for the assessment were considered from 25 Member states (MS) across Europe. The stocktake shows that availability of datasets concerning soil carbon sequestration (SCS) is variable among Europe. While northern Europe and central Europe is relatively well studied, there is a lack of studies comprising parts of Southern, Southeaster and Western Europe. Further, it can be concluded that at present country based knowledge and engagement is still poor; very few countries have an idea on their national-wide achievable carbon sequestration potential. The presented national SCS potentials (MS n=13) do however point towards important contributions to mitigate climate change by covering considerable shares of national greenhouse gas emissions from the agricultural sector in the range of 0.1-27 %, underpinning the importance of further investigations. In contrast to mineral soils, effective mitigation measures for organic soils while maintaining industrial agricultural production are still in its infancy. Very few mitigation options exist to mitigate GHG emissions without compromising agricultural production. Most GHG mitigation practices reported by the MS involve the restoration of organic soils, which means a complete abandonment of land from any agricultural use. Only one contribution (NL) reports possible mitigation potentials, which are based on specific water management measures (water level fixation). Nevertheless, there is an increasing awareness of the need of mitigation measures reflected by the several ongoing research projects on peatland management.
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.
Authors
Daniel RasseAbstract
No abstract has been registered
Authors
Bertrand Guenet Benoit Gabrielle Claire Chenu Dominique Arrouays Jerome Balesdent Martial Bernoux Elisa Bruni Jean-Pierre Caliman Remi Cardinael Songchao Chen Philippe Ciais Dominique Desbois Julien Fouche Stefan Frank Cathrine Henault Emanuele Lugato Victoria Naipal Thomas Nesme Michael Obersteiner Sylvain Pellerin David S. Powlson Daniel Rasse Frédéric Rees Jean-Francois Soussana Yang Su Hanqin Tian Hugo Valin Feng ZhouAbstract
To respect the Paris agreement targeting a limitation of global warming below 2°C by 2100, and possibly below 1.5 °C, drastic reductions of greenhouse gas emissions are mandatory but not sufficient. Large‐scale deployment of other climate mitigation strategies are also necessary. Among these, increasing soil organic carbon (SOC) stocks is an important lever because carbon in soils can be stored for long periods and land management options to achieve this already exist and have been widely tested. However, agricultural soils are also an important source of nitrous oxide (N2O), a powerful greenhouse gas, and increasing SOC may influence N2O emissions, likely causing an increase in many cases, thus tending to offset the climate change benefit from increased SOC storage. Here, we review the main agricultural management options for increasing SOC stocks. We evaluate the amount of SOC that can be stored as well as resulting changes in N2O emissions to better estimate the climate benefits of these management options. Based on quantitative data obtained from published meta‐analyses and from our current level of understanding, we conclude that the climate mitigation induced by increased SOC storage is generally overestimated if associated N2O emissions are not considered but, with the exception of reduced tillage, is never fully offset. Some options (e.g, biochar or non‐pyrogenic C amendment application) may even decrease N2O emissions.
Authors
Gaby Deckmyn Omar Flores Mathias Mayer Xavier Domene Andrea Schnepf Katrin Kuka Kris Van Looy Daniel Rasse Maria J.I. Briones Sébastien Barot Matty Berg Elena Vanguelova Ivika Ostonen Harry Vereecken Laura M. Suz Beat Frey Aline Frossard Alexei Tiunov Jan Frouz Tine Grebenc Maarja Öpik Mathieu Javaux Alexei Uvarov Olga Vindušková Paul Henning Krogh Oskar Franklin Juan Jimenez Jorge Curiel YusteAbstract
The relatively poor simulation of the below-ground processes is a severe drawback for many ecosystem models, especially when predicting responses to climate change and management. For a meaningful estimation of ecosystem production and the cycling of water, energy, nutrients and carbon, the integration of soil processes and the exchanges at the surface is crucial. It is increasingly recognized that soil biota play an important role in soil organic carbon and nutrient cycling, shaping soil structure and hydrological properties through their activity, and in water and nutrient uptake by plants through mycorrhizal processes. In this article, we review the main soil biological actors (microbiota, fauna and roots) and their effects on soil functioning. We review to what extent they have been included in soil models and propose which of them could be included in ecosystem models. We show that the model representation of the soil food web, the impact of soil ecosystem engineers on soil structure and the related effects on hydrology and soil organic matter (SOM) stabilization are key issues in improving ecosystem-scale soil representation in models. Finally, we describe a new core model concept (KEYLINK) that integrates insights from SOM models, structural models and food web models to simulate the living soil at an ecosystem scale.
Abstract
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Authors
Daniel RasseAbstract
No abstract has been registered
Abstract
No abstract has been registered
Abstract
At the Norwegian Institute of Bioeconomy Research (NIBIO, formerly Bioforsk), biochar has been a topic of research since 2009 through both laboratory and field studies. Initial results demonstrated that biochar produced from clean biomass is safe to use on agricultural soils, and that pyrolysis temperatures of ≥370 °C are necessary for producing biochar that is resistant to decomposition on a timescale of 100 years. Further work identified the chemical transformations that are responsible for biochar stability and contributed to finding the best indicator of this stability. Throughout the years, we have had close collaboration with industry and farmers in Norway, where now industrial networks are in action and there is financial support for the implementation of biochar technology. Despite the convincing benefits of biochar as a climate mitigation solution, it has only slowly advanced beyond the research stage, notably because its effect on yield are too modest. There is therefore a need for win-win biochar solutions benefiting both food production and climate mitigation. Such a solution is the development of biochar fertilizers, which capitalizes on the capacity of biochar to capture and release nutrients. As biochar properties largely depend on pyrolysis conditions and feedstock properties, our current work contributes to the selective design of biochars for the purpose of improving nutrient use efficiency.
Authors
Daniel RasseAbstract
No abstract has been registered
Abstract
Mediterranean climate areas are home to highly relevant and distinctive agro-ecosystems, where sustainability is threatened by water scarcity and continuous loss of soil organic carbon. In these systems, recycling strategies to close the loop between crop production (and agrorelated industries) and soil conservation are of special interest in the current context of climate change mitigation. Pyrolysis represents a recycling option for the production of energy and biochar, a carbonaceous product with a wide range of environmental and agronomic applications. Considering that biochar functionality depends on both the original biomass and the pyrolysis conditions, we produced and characterized 22 biochars in order to evaluate their potential to sequester C and modify soil physicochemical properties. The pore size distribution was a function of the original biomass and did not change with the temperature of pyrolysis. The highest number of pores within the size 0.2−30 μm, relevant for plant available water retention, was reached at 600 °C. However, ideal pyrolysis conditions to optimize C stability and hydrologic properties was reached at 400 °C in woody derived biochars, as higher temperatures lead to a nontransient hydrophobicity. This study highlights relevant physicochemical properties of locally derived biochars that can be used to tackle specific challenges in Mediterranean agroecosystems.
Authors
Christophe Moni Hanna Marika Silvennoinen Bruce A. Kimball Erling Fjelldal Marius Brenden Ingunn Burud Andreas Svarstad Flø Daniel RasseAbstract
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.
Authors
Daniel RasseAbstract
No abstract has been registered
Authors
Pete Smith Jean-Francois Soussana Denis Angers Louis Schipper Claire Chenu Daniel Rasse Niels H. Batjes Fenny van Egmond Stephen McNeill Matthias Kuhnert Cristina Arias‐Navarro Jørgen E. Olesen Ngonidzashe Chirinda Dario Fornara Eva Wollenberg Jorge Álvaro-Fuentes Alberto Sanz-Cobena Katja KlumppAbstract
There is growing international interest in better managing soils to increase soil organic carbon (SOC) content to contribute to climate change mitigation, to enhance resilience to climate change and to underpin food security, through initiatives such as international ‘4p1000’ initiative and the FAO's Global assessment of SOC sequestration potential (GSOCseq) programme. Since SOC content of soils cannot be easily measured, a key barrier to implementing programmes to increase SOC at large scale, is the need for credible and reliable measurement/monitoring, reporting and verification (MRV) platforms, both for national reporting and for emissions trading. Without such platforms, investments could be considered risky. In this paper, we review methods and challenges of measuring SOC change directly in soils, before examining some recent novel developments that show promise for quantifying SOC. We describe how repeat soil surveys are used to estimate changes in SOC over time, and how long‐term experiments and space‐for‐time substitution sites can serve as sources of knowledge and can be used to test models, and as potential benchmark sites in global frameworks to estimate SOC change. We briefly consider models that can be used to simulate and project change in SOC and examine the MRV platforms for SOC change already in use in various countries/regions. In the final section, we bring together the various components described in this review, to describe a new vision for a global framework for MRV of SOC change, to support national and international initiatives seeking to effect change in the way we manage our soils.
Abstract
No abstract has been registered
Abstract
Biochar has been shown to reduce nitrous oxide (N2O) emissions from soils, but the effect is highly variable across studies and the mechanisms are under debate. To improve our mechanistic understanding of biochar effects on N2O emission, we monitored kinetics of NO, N2O and N2 accumulation in anoxic slurries of a peat and a mineral soil, spiked with nitrate and amended with feedstock dried at 105 °C and biochar produced at 372, 416, 562 and 796 °C at five different doses. Both soils accumulated consistently less N2O and NO in the presence of high-temperature chars (BC562 and BC796), which stimulated reduction of denitrification intermediates to N2, particularly in the acid peat. This effect appeared to be strongly linked to the degree of biochar carbonisation as predicted by the H:C ratio of the char. In addition, biochar surface area and pH were identified as important factors, whereas ash content and CEC played a minor role. At low pyrolysis temperature, the biochar effect was soil dependent, suppressing N2O accumulation in the mineral soil, but enhancing it in the peat soil. This contrast was likely due to the labile carbon content of low temperature chars, which contributed to immobilise N in the mineral soil, but stimulated denitrification and N2O emission in the peat soil. We conclude that biochar with a high degree of carbonisation, high pH and high surface area is best suited to supress N2O emission from denitrification, while low temperature chars risk supporting incomplete denitrification.
Abstract
Biochar is a carbon-rich material that, due to its inherent resistance to decomposition, is primarily developed with the aim of sequestering carbon in soil. Despite the convincing benefits of biochar as a climate mitigation solution, it has not yet advanced much beyond the research stage, notably because its effect on yield are too modest. Therefore, there is a need for win-win biochar solutions benefiting both food production and climate mitigation. Such a solution is the development of biochar fertilizers, which capitalizes on the capacity of biochar to capture and release nutrients. This effect is largely attributed to the porous structure and large surface area of biochar, with surface charges and ash content also appearing to play a role. The nutrient-retaining capacity of biochar appears to vary among studies investigating different types of biochar exposed to different types of nutrients (mineral anions and cations, organic molecules) under different conditions. In the present study, we will report on a meta-analysis of published biochar properties that are associated with controlling the sorption of nutrients. As biochar properties largely depend on pyrolysis conditions and feedstock properties, this work contributes to the selective design of biochars for the purpose of improving nutrient use efficiency.
Abstract
Norway is strongly committed to the Paris Climate Agreement with an ambitious goal of 40% reduction in greenhouse gas emission by 2030. The land sector, including agriculture and forestry, must critically contribute to this national target. Beyond emission reduction, the land sector has the unique capacity to actively removing CO2 from the atmosphere through biological carbon storage in biomass and in soils. Soils are the largest reservoir of terrestrial carbon, and relatively small changes in soil carbon content can have an amplified mitigation effect on the Earth’s climate. Therefore, improved management of soils for carbon storage is receiving a lot of attention, for example through international political initiatives such as the “4-permill” initiative. However, in Norway, many mitigation measures targeting soil carbon might negatively impact food production and economic activity. For example, soil carbon storage can be increased by shifting from cereal crop production to grasslands, but Norway already has abundant grassland and a comparatively small area dedicated to cereals. Another such issue is cultivation on drained peatland, where food is produced at the expense of large losses of soil carbon as CO2 to the atmosphere. Therefore, there is a need to look for win-win solutions for soil carbon storage, which benefit both food production and climate mitigation. Large-scale conversion of agricultural and forest waste biomass to biochar is such an option, and is considered the activity with the largest potential for soil carbon sequestration in Norway. Biochar has been demonstrated to have a mean residence time exceeding 100 years in Norwegian field conditions (Rasse et al, 2017), and no negative effects on plant and soils has been observed. However, despite the convincing benefits of biochar as a climate mitigation solution, it has not yet advanced much beyond the research stage, notably because its effect on yield are too modest. Here, we will first present the comparative advantage of biochar technology as compared to traditional agronomy methods for large-scale C storage in Norwegian agricultural soils. We will further discuss the need for developing innovations in pyrolysis and nutrient-rich waste recycling leading to biochar-fertilizer products as win-win solution for carbon storage and food production.
Authors
Daniel RasseAbstract
No abstract has been registered
Abstract
No abstract has been registered
Authors
Adam O´Toole Christophe Moni Simon Weldon Anne Schols Monique Carnol Bernard Bosman Daniel RasseAbstract
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.
Authors
Chunjing Qiu Dan Zhu Philippe Ciais Bertrand Guenet Gerhard Krinner Shushi Peng Mika Aurela Christian Bernhofer Christian Brümmer Syndonia Bret-Harte Housen Chu Jiquan Chen Ankur R. Desai Jiří Dušek Eugénie S. Euskirchen Krzysztof Fortuniak Lawrence B. Flanagan Thomas Friborg Mateusz Grygoruk Sébastien Gogo Thomas Grünwald Birger U. Hansen David Holl Elyn Humphreys Miriam Hurkuck Gerard Kiely Janina Klatt Lars Kutzbach Chloé Largeron Fatima Laggoun-Défarge Magnus Lund Peter M. Lafleur Xuefei Li Ivan Mammarella Lutz Merbold Mats B. Nilsson Janusz Olejnik Mikaell Ottosson-Löfvenius Walter C. Oechel Frans-Jan W. Parmentier Matthias Peichl Norbert Pirk Olli Peltola Włodzimierz Pawlak Daniel Rasse Janne Rinne Gaius R. Shaver Hans Peter Schmid Matteo Sottocornola Rainer Steinbrecher Torsten Sachs Marek Urbaniak Donatella Zona Klaudia ZiemblinskaAbstract
Peatlands store substantial amounts of carbon and are vulnerable to climate change. We present a modified version of the Organising Carbon and Hydrology In Dynamic Ecosystems (ORCHIDEE) land surface model for simulating the hydrology, surface energy, and CO2 fluxes of peatlands on daily to annual timescales. The model includes a separate soil tile in each 0.5° grid cell, defined from a global peatland map and identified with peat-specific soil hydraulic properties. Runoff from non-peat vegetation within a grid cell containing a fraction of peat is routed to this peat soil tile, which maintains shallow water tables. The water table position separates oxic from anoxic decomposition. The model was evaluated against eddy-covariance (EC) observations from 30 northern peatland sites, with the maximum rate of carboxylation (Vcmax) being optimized at each site. Regarding short-term day-to-day variations, the model performance was good for gross primary production (GPP) (r2 = 0.76; Nash–Sutcliffe modeling efficiency, MEF = 0.76) and ecosystem respiration (ER, r2 = 0.78, MEF = 0.75), with lesser accuracy for latent heat fluxes (LE, r2 = 0.42, MEF = 0.14) and and net ecosystem CO2 exchange (NEE, r2 = 0.38, MEF = 0.26). Seasonal variations in GPP, ER, NEE, and energy fluxes on monthly scales showed moderate to high r2 values (0.57–0.86). For spatial across-site gradients of annual mean GPP, ER, NEE, and LE, r2 values of 0.93, 0.89, 0.27, and 0.71 were achieved, respectively. Water table (WT) variation was not well predicted (r2 < 0.1), likely due to the uncertain water input to the peat from surrounding areas. However, the poor performance of WT simulation did not greatly affect predictions of ER and NEE. We found a significant relationship between optimized Vcmax and latitude (temperature), which better reflects the spatial gradients of annual NEE than using an average Vcmax value.
Authors
Frans-Jan W. Parmentier Daniel Rasse Magnus Lund Jarle W. Bjerke Bert G. Drake Simon Weldon Hans Tømmervik Georg Heinrich HansenAbstract
Extreme winter events that damage vegetation are considered an important climatic cause of arctic browning—a reversal of the greening trend of the region—and possibly reduce the carbon uptake of northern ecosystems. Confirmation of a reduction in CO2 uptake due to winter damage, however, remains elusive due to a lack of flux measurements from affected ecosystems. In this study, we report eddy covariance fluxes of CO2 from a peatland in northern Norway and show that vegetation CO2 uptake was delayed and reduced in the summer of 2014 following an extreme winter event earlier that year. Strong frost in the absence of a protective snow cover—its combined intensity unprecedented in the local climate record—caused severe dieback of the dwarf shrub species Calluna vulgaris and Empetrum nigrum. Similar vegetation damage was reported at the time along ~1000 km of coastal Norway, showing the widespread impact of this event. Our results indicate that gross primary production (GPP) exhibited a delayed response to temperature following snowmelt. From snowmelt up to the peak of summer, this reduced carbon uptake by 14 (0–24) g C m−2 (~12% of GPP in that period)—similar to the effect of interannual variations in summer weather. Concurrently, remotely-sensed NDVI dropped to the lowest level in more than a decade. However, bulk photosynthesis was eventually stimulated by the warm and sunny summer, raising total GPP. Species other than the vulnerable shrubs were probably resilient to the extreme winter event. The warm summer also increased ecosystem respiration, which limited net carbon uptake. This study shows that damage from a single extreme winter event can have an ecosystem-wide impact on CO2 uptake, and highlights the importance of including winter-induced shrub damage in terrestrial ecosystem models to accurately predict trends in vegetation productivity and carbon sequestration in the Arctic and sub-Arctic.
Authors
Claudia Kammann Jim Ippolito Nikolas Hagemann Nils Borchard Maria Luz Cayuela José M. Estavillo Teresa Fuertes-Mendizabal Simon Jeffery Jürgen Kern Jeff Novak Daniel Rasse Sanna Saarnio Hans-Peter Schmidt Kurt Spokas Nicole Wrage-MönnigAbstract
Agriculture and land use change has significantly increased atmospheric emissions of the non-CO2 green-house gases (GHG) nitrous oxide (N2O) and methane (CH4). Since human nutritional and bioenergy needs continue to increase, at a shrinking global land area for production, novel land management strategies are required that reduce the GHG footprint per unit of yield. Here we review the potential of biochar to reduce N2O and CH4 emissions from agricultural practices including potential mechanisms behind observed effects. Furthermore, we investigate alternative uses of biochar in agricultural land management that may significantly reduce the GHG-emissions-per-unit-of-product footprint, such as (i) pyrolysis of manures as hygienic alternative to direct soil application, (ii) using biochar as fertilizer carrier matrix for underfoot fertilization, biochar use (iii) as composting additive or (iv) as feed additive in animal husbandry or for manure treatment. We conclude that the largest future research needs lay in conducting life-cycle GHG assessments when using biochar as an on-farm management tool for nutrient-rich biomass waste streams.
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Frans-Jan W. Parmentier Daniel Rasse Magnus Lund Jarle W. Bjerke Bert G. Drake Simon Weldon Hans Tømmervik Georg Heinrich Hansen Lennart Nilsen Elisabeth J. CooperAbstract
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Authors
Daniel RasseAbstract
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Frans-Jan W. Parmentier Daniel Rasse Magnus Lund Jarle W. Bjerke Bert G. Drake Simon Weldon Hans Tømmervik Georg Heinrich HansenAbstract
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Authors
Alice Budai Lucia Calucci Daniel Rasse Line Tau Strand Annelene Pengerud Daniel Wiedemeier Samuel Abiven Claudia ForteAbstract
Infrared and 13C solid state nuclear magnetic resonance spectroscopies and benzene polycarboxylic acids (BPCA) analysis were used to characterize the structural changes occurring during slow pyrolysis of corncob and Miscanthus at different temperatures from 235 °C to 800 °C. In the case of corncob, a char sample obtained from flash carbonization was also investigated. Spectroscopic techniques gave detailed information on the transformations of the different biomass components, whereas BPCA analysis allowed the amount of aromatic structures present in the different chars and the degree of aromatic condensation to be determined. The results showed that above 500 °C both corncob and Miscanthus give polyaromatic solid residues with similar degree of aromatic condensation but with differences in the structure. On the other hand, at lower temperatures, char composition was observed to depend on the different cellulose/hemicellulose/lignin ratios in the feedstocks. Flash carbonization was found to mainly affect the degree of aromatic condensation.
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Frans-Jan W. Parmentier Daniel Rasse Magnus Lund Jarle W. Bjerke Bert G. Drake Simon Weldon Hans Tømmervik Georg Heinrich Hansen Lennart Nilsen Elisabeth J. CooperAbstract
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Evaluating biochars for their persistence in soil under field conditions is an important step towards their implementation for carbon sequestration. Current evaluations might be biased because the vast majority of studies are short-term laboratory incubations of biochars produced in laboratory-scale pyrolyzers. Here our objective was to investigate the stability of a biochar produced with a medium-scale pyrolyzer, first through laboratory characterization and stability tests and then through field experiment. We also aimed at relating properties of this medium-scale biochar to that of a laboratory-made biochar with the same feedstock. Biochars were made of Miscanthus biomass for isotopic C-tracing purposes and produced at temperatures between 600 and 700°C. The aromaticity and degree of condensation of aromatic rings of the medium-scale biochar was high, as was its resistance to chemical oxidation. In a 90-day laboratory incubation, cumulative mineralization was 0.1% for the medium-scale biochar vs. 45% for the Miscanthus feedstock, pointing to the absence of labile C pool in the biochar. These stability results were very close to those obtained for biochar produced at laboratory-scale, suggesting that upscaling from laboratory to medium-scale pyrolyzers had little effect on biochar stability. In the field, the medium-scale biochar applied at up to 25 t C ha-1 decomposed at an estimated 0.8% per year. In conclusion, our biochar scored high on stability indices in the laboratory and displayed a mean residence time > 100 years in the field, which is the threshold for permanent removal in C sequestration projects.
Authors
Annelene Pengerud Marie-France Dignac Giacomo Certini Line Tau Strand Claudia Forte Daniel RasseAbstract
Increased mineralization of the organic matter (OM) stored in permafrost is expected to constitute the largest additional global warming potential from terrestrial ecosystems exposed to a warmer climate. Chemical composition of permafrost OM is thought to be a key factor controlling the sensitivity of decomposition to warming. Our objective was to characterise OM from permafrost soils of the European Arctic: two mineral soils—Adventdalen, Svalbard, Norway and Vorkuta, northwest Russia— and a ‘‘palsa’’ (ice-cored peat mound patterning in heterogeneous permafrost landscapes) soil in Neiden, northern Norway, in terms of molecular composition and state of decomposition. At all sites, the OM stored in the permafrost was at an advanced stage of decomposition, although somewhat less so in the palsa peat. By comparing permafrost and active layers, we found no consistent effect of depth or permafrost on soil organic matter (SOM) chemistry across sites. The permafrost-affected palsa peat displayed better preservation of plant material in the deeper layer, as indicated by increasing contribution of lignin carbon to total carbon with depth, associated to decreasing acid (Ac) to aldehyde (Al) ratio of the syringyl (S) and vanillyl (V) units, and increasing S/V and contribution of plant-derived sugars. By contrast, in Adventdalen, the Ac/Al ratio of lignin and the Alkyl C to O-alkyl C ratio in the NMR spectra increased with depth, which suggests less oxidized SOM in the active layer compared to the permafrost layer. In Vorkuta, SOM characteristics in the permafrost profile did not change substantially with depth, probably due to mixing of soil layers by cryoturbation. The composition and state of decomposition of SOM appeared to be site-specific, in particular bound to the prevailing organic or mineral nature of soil when attempting to predict the SOM proneness to degradation. The occurrence of processes such as palsa formation in organic soils and cryoturbation should be considered when up-scaling and predicting the responses of OM to climate change in arctic soils.
Authors
Lea Piscitelli Pierre-Adrien Rivier Donato Mondelli Teodoro Miano Daniel Rasse Erik J. JonerAbstract
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Hanna Marika Silvennoinen Christophe Moni Teresa Gómez de la Bárcena Mats Höglind Daniel RasseAbstract
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Daniel RasseAbstract
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Esben Bruun Andrew Cross Jim Hammond Victoria Nelissen Daniel Rasse Henrik Hauggaard-NielsenAbstract
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Daniel RasseAbstract
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Biochar and its properties can be significantly altered according to how it is produced, and this has ramifications towards how biochar behaves once added to soil. We produced biochars from corncob and miscanthus straw via different methods (slow pyrolysis, hydrothermal and flash carbonization) and temperatures to assess how carbon cycling and soil microbial communities were affected. Mineralization of biochar, its parent feedstock, and native soil organic matter were monitored using 13C natural abundance during a 1-year lab incubation. Bacterial and fungal community compositions were studied using T-RFLP and ARISA, respectively. We found that persistent biochar-C with a half-life 60 times higher than the parent feedstock can be achieved at pyrolysis temperatures of as low as 370 °C, with no further gains to be made at higher temperatures. Biochar re-applied to soil previously incubated with our highest temperature biochar mineralized faster than when applied to unamended soil. Positive priming of native SOC was observed for all amendments but subsided by the end of the incubation. Fungal and bacterial community composition of the soil-biochar mixture changed increasingly with the application of biochars produced at higher temperatures as compared to unamended soil. Those changes were significantly (P < 0.005) related to biochar properties (mainly pH and O/C) and thus were correlated to pyrolysis temperature. In conclusion, our results suggest that biochar produced at temperatures as low as 370 °C can be utilized to sequester C in soil for more than 100 years while having less impact on soil microbial activities than high-temperature biochars.
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Elisa Lopez-Capel Kor Zwart Simon Shackley Romke Postma John Stenström Daniel Rasse Alice Budai Bruno GlaserAbstract
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Daniel RasseAbstract
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Hanna Marika Silvennoinen Teresa Gómez de la Bárcena Christophe Moni Marcin Szychowski Paulina Rajewicz Daniel RasseAbstract
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Hanna Marika Silvennoinen Mats Höglind Christophe Moni Ingunn Burud Erling Fjelldal Daniel RasseAbstract
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A. Lagomarsino A. E. Agnelli R. Pastorelli G. Pallara Daniel Rasse Hanna Marika SilvennoinenAbstract
The water management system of cultivated paddy rice soils is one of the most important factors affecting the respective magnitudes of CH4 and N2O emissions. We hypothesized an effect of past management on soil microbial communities and greenhouse gas (GHG) production potential. The ob- jectives of this study were to i) assess the influence of water management history on GHG production and microbial community structure, ii) relate GHG production to the microbial communities involved in CH4 and N2O production inhabiting the different soils. Moreover, the influence of different soil condi- tioning procedures on GHG production was determined. To reach these aims, we compared four soils with different water management history, using dried and sieved, pre-incubated and fresh soils. Soil conditioning procedures strongly affected GHG production: drying and sieving induced the highest production rates and the largest differences among soil types, probably through the release of labile substrates. Conversely, soil pre-incubation tended to homogenize and level out the differences among soils. The water management history strongly affected microbial community structure, which was itself tightly linked to CH4 and N2O production. N2O production was the highest in aerobic soil, which also exhibited the strongest evidence for active nitrifying communities (NirK). Drying and rewetting aerobic soil enhanced the production of nitrate, which was further reduced to N2O through denitrification. As expected, CH4 production was the lowest in aerobic soil, which showed a less abundant archaeal com- munity. This work supports the hypothesis that microbial communities in paddy soils progressively adapt to water management practices, thereby reinforcing potential differences in GHGs production.
Authors
Ma Xingzhu Baoku Zhou Alice Budai Alhaji S. Jeng Xiaoyu Hao Dan Wei Yulan Zhang Daniel RasseAbstract
Biochar is a carbon-rich solid product obtained by pyrolysis of biomass. Here, we investigated multiple biochars produced under slow pyrolysis (235–800 °C), flash carbonization, and hydrothermal carbonization (HTC), using Scanning Electron Microscope—Energy Dispersive X-ray Spectroscopy (SEM-EDX) in order to determine whether SEM-EDX can be used as a proxy to characterize biochars effectively. Morphological analysis showed that feedstock has an integrated structure compared to biochar; more pores were generated, and the size became smaller when the temperature increased. Maximum carbon content (max. C) and average carbon content (avg. C) obtained from SEM-EDX exhibited a positive relationship with pyrolysis temperature, with max. C correlating most closely with dry combustion total carbon content. The SEM-EDX O/C ratios displayed a consistent response with the highest treatment temperature (HTT). The study suggests that SEM-EDX produces highly consistent C, oxygen (O), and C/O ratios that deserve further investigation as an operational tool for characterization of biochar products.
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Frans-Jan W. Parmentier Daniel Rasse Georg Heinrich Hansen Jarle W. Bjerke Simon Weldon Magnus LundAbstract
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Alessandra Lagomarsino Bruce Linquist Arlene Adviento-Borbe Rossana Monica Ferrara Roberta Pastorelli Grazia Pallara Daniel Rasse Hanna Marika SilvennoinenAbstract
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Daniel RasseAbstract
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Daniel RasseAbstract
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Alice Budai Daniel Rasse Claudia Forte Line Tau Strand Samuel Abiven C. Rumpel Annelene Pengerud Alain Plante M. A. AlexisAbstract
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Georg Heinrich Hansen Daniel Rasse Heleen de Wit Hans Tømmervik Jarle W. Bjerke Magnus Lund Frans-Jan W. ParmentierAbstract
Greenhouse gas exchange between terrestrial ecosystems and the atmosphere are an important element of the climate system. Especially boreal and polar wetlands and peatlands may play a crucial role for the future development of atmospheric carbon dioxide and methane concentrations, because they contain stores of these gases in the same order of magnitude as the current atmospheric load. The aim of this project was to estimate the fluxes of CO2 and CH4 from an oceanic wetland in North‐Norway. Seven years of observations reveal that carbon exchange from this ecosystem is comparable to that of moderate zone coastal wetlands, but distinctly different from alpine and continental wetlands at the same latitude in Sweden and Finland. The seven‐year record of meteorological data reveals that the observed period was significantly warmer (especially during winter) and drier (especially in summer) than the climate reference period 1961‐1990. Carbon fluxes during the growing season are sensitive to both draught, cold spells and soil climate conditions before the onset of the growing season, but the annual Net Ecosystem Exchange is much less variable.
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Magnus Lund Jarle W. Bjerke Bert G. Drake Ola Engelsen Georg Heinrich Hansen Frans-Jan W. Parmentier Thomas Powell Hanna Marika Silvennoinen Matteo Sottocornola Hans Tømmervik Simon Weldon Daniel RasseAbstract
Northern peatlands hold large amounts of organic carbon (C) in their soils and are as such important in a climate change context. Blanket bogs, i.e. nutrient-poor peatlands restricted to maritime climates, may be extra vulnerable to global warming since they require a positive water balance to sustain their moss dominated vegetation andCsink functioning. This study presents a 4.5 year record of land– atmosphere carbon dioxide (CO2) exchange from the Andøya blanket bog in northern Norway. Compared with other peatlands, the Andøya peatland exhibited low flux rates, related to the low productivity of the dominating moss and lichen communities and the maritime settings that attenuated seasonal temperature variations. It was observed that under periods of high vapour pressure deficit, net ecosystem exchange was reduced, which was mainly caused by a decrease in gross primary production. However, no persistent effects of dry conditions on theCO2 exchange dynamics were observed, indicating that under present conditions and within the range of observed meteorological conditions the Andøya blanket bog retained its Cuptake function. Continued monitoring of these ecosystem types is essential in order to detect possible effects of a changing climate. peatland, carbon, blanket bog, eddy covariance, climate change, net ecosystem exchange
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Daniel RasseAbstract
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Ingunn Burud Christophe Moni Andreas Svarstad Flø Cecilia Marie Futsæther Markus Steffens Daniel RasseAbstract
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Christophe Moni Thomas Lerch Katrin Knoth Line Tau Strand Claudia Forte Giacomo Certini Daniel RasseAbstract
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Alessandra Lagomarsino Alessandroelio Agnelli Roberta Pastorelli Grazia Pallara Daniel Rasse Hanna Marika SilvennoinenAbstract
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Christophe Moni Hanna Marika Silvennoinen Erling Fjelldal M. Brenden B. Kimball Daniel RasseAbstract
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Authors
Herbert N. Mbufong Magnus Lund Mika Aurela Torben Röjle Christensen Werner Eugster Thomas Friborg Birger Ulf Hansen Elyn R. Humphreys Marcin Jackowicz-Korczyński Lars Kutzbach Peter M. Lafleur Walter C. Oechel Frans-Jan W. Parmentier Daniel Rasse A.V. Rocha Torsten Sachs Michiel K. Van Der Molen M.P. TamstorfAbstract
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Studies examining the effect of biochar on N2O turnover in soil have demonstrated that biochar affects both the rate and product ratio of denitrification. The mechanisms proposed include pH effects on N2O reductase , sorption of N2O and electron shuttling to N2O reductases. Recent studies suggest that pyrolysis alters the redox chemistry of biochar leading to the formation of redox active compounds which are thought to mediate the observed suppression of N2O in biochar amended soil. Redox active components however may not only be of significance to biological processes but also catalyze abiotic reactions of N-species which could confound the estimation of biological effects. Here we report experiments designed to examined abiotic interaction between biochar and NO in anoxic water slurries with biochar of increasing pyrolysis temperature. We determined the fate of NO added to the headspace of closed anoxic bottles using high frequency measurements of NO, N2O and N2. Our initial results show a swift disappearance of added NO which can not entirely be attributed to sorption to the biochar. Small but constant quantities of N2O were generated after NO addition indicating abiotic turnover of NO by biochar. NO is an important signal molecule in the regulation of denitrification and hence it is important to elucidate possible abiotic feedbacks of NO reactions in soil. The results will be discussed relative to the redox properties of the biochars tested.
Abstract
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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Authors
Alice Budai Liang Wang Morten Grønli Line Tau Strand Michael Jerry Antal, Jr Samuel Abiven Alba Dieguez-Alonso Andrés Anca-Couce Daniel RasseAbstract
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Hanna Marika Silvennoinen Adam O´Toole Katrin Knoth Monique Carnol Peter Dörsch Daniel RasseAbstract
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Authors
Nate McDowell Rosie A. Fisher Chonggang Xu J.C. Domec Teemu Hölttä D. Scott Mackay John Sperry Amanda Boutz L Dickmann Nathan Gehres Jean Marc Limousin Alison Macalady Jordi Maritinez-Vilalta Maurizio Mencuccini Jennifer Plaut Jèrôme Ogèe Robert E. Pangle Daniel Rasse Michael G. Ryan Sanna Sevanto Richard H. Waring A. Park Williams Enrico A. Yepez William T. PockmanAbstract
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Authors
Alice Budai Liang Wang Morten Grønli Line Tau Strand Samuel Abiven Alba Dieguez-Alonso Andrés Anca-Couce Daniel RasseAbstract
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Authors
Magnus Lund Jarle Werner Bjerke Bert G. Drake O Engelsen Georg Heinrich Hansen F.J.W. Parmentier Thomas L. Powell H. Silvennoinen Hans Tømmervik Simon Weldon Daniel RasseAbstract
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Authors
Alice Budai Samuel Abiven Morten Grønli Liang Wang Michael Jerry Antal Claudia Forte Daniel RasseAbstract
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Authors
A.E. Bond R. Metcalfe P. Suckling K. Tatcher R. Walke K. Smith Daniel Rasse M. Steven D. JonesAbstract
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Authors
Daniel RasseAbstract
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Authors
Daniel RasseAbstract
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Daniel RasseAbstract
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Daniel RasseAbstract
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Authors
Michael W.I. Schmidt Margaret S. Torn Samuel Abiven Thorsten Dittmar Georg Guggenberger Ivan A. Janssens Markus Kleber Ingrid Kögel-Knabner Johannes Lehmann David A.C. Manning Paolo Nannipieri Daniel Rasse Steve Weiner Susan E. TrumboreAbstract
Globally, soil organic matter (SOM) contains more than three times as much carbon as either the atmosphere or terrestrial vegetation. Yet it remains largely unknown why some SOM persists for millennia whereas other SOM decomposes readily—and this limits our ability to predict how soils will respond to climate change. Recent analytical and experimental advances have demonstrated that molecular structure alone does not control SOM stability: in fact, environmental and biological controls predominate. Here we propose ways to include this understanding in a new generation of experiments and soil carbon models, thereby improving predictions of the SOM response to global warming.
Abstract
The aliphatic biopolyesters cutins and suberins have been suggested to significantly contribute to the stable pool of soil organic matter (SOM), and to be tracers for the above- or belowground origin of plant material. Contrary to other plant-derived aliphatic molecules found in the lipid fraction of soils, the stable isotope derived estimates of turnover of cutins and suberins have never been studied in soils. The aim of this study was to analyse the dynamics of shoot- and root-derived biomarkers in soils using a wheat and maize (C3/C4) chronosequence, where changes in the natural 13C abundance can be used to evaluate the incorporation of new carbon into SOM at the molecular level. The relative distribution of aliphatic monomers in wheat and maize roots and shoots suggested that a,u-alkanedioic acids can be considered as root-specific markers and mid-chain hydroxy acids as shoot-specific markers. The contrasting distribution of the plant-specific monomers in plants and soils might be explained by different chemical mechanisms leading to selective degradation or stabilization of some biomarkers. The changes of the 13C isotopic signatures of these markers with years of maize cropping after wheat evidenced their contrasted behaviour in soil. After 12 years of maize cropping, shoot markers present in soil samples probably originated from old C3 vegetation suggesting that new maize cutin added to soils was mostly degraded within a year. The reasons for long-term stabilization of shoot biomarkers remain unclear. By contrast, maize root markers were highly incorporated into SOM during the first six years of maize crop, which suggested a selective preservation of root biomass when compared to shoots, possibly due to physical protection.
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The molecular composition of plant residues is suspected to largely govern the fate of their constitutive carbon (C) in soils. Labile compounds, such as metabolic carbohydrates, are affected differently from recalcitrant and structural compounds by soil-C stabilisation mechanisms. Producing 13C-enriched plant residues with specifically labeled fractions would help us to investigate the fate in soils of the constitutive C of these compounds. The objective of the present research was to test 13C pulse chase labeling as a method for specifically enriching the metabolic carbohydrate components of plant residues, i.e. soluble sugars and starch. Bean plants were exposed to a 13CO2-enriched atmosphere for 0.5, 1, 2, 3 and 21 h. The major soluble sugars were then determined on watersoluble extracts, and starch on HCl-hydrolysable extracts. The results show a quick differential labeling between water-soluble and water-insoluble compounds. For both groups, 13C-labeling increased linearly with time. The difference in δ13C signature between water-soluble and insoluble fractions was 7% after 0.5 h and 70% after 21 h. However, this clear isotopic contrast masked a substantial labeling variability within each fraction. By contrast, metabolic carbohydrates on the one hand (i.e. soluble sugarsRstarch) and other fractions (essentially cell wall components) on the other hand displayed quite homogeneous signatures within fractions, and a significant difference in labeling between fractions: δ13C=414±3.7% and 56±5.5%, respectively. Thus, the technique generates labeled plant residues displaying contrasting 13C-isotopic signatures between metabolic carbohydrates and other compounds, with homogenous signatures within each group. Metabolic carbohydrates being labile compounds, our findings suggest that the technique is particularly appropriate for investigating the effect of compound lability on the long-term storage of their constitutive C in soils.
Authors
Troy J. Seiler Daniel Rasse Jiahong Li Paul Dijkstra Hans P. Anderson David P. Johnson Thomas L. Powell Bruce A. Hungate C. Ross Hinkle Bert G. DrakeAbstract
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