| 1. |
- Abiven, Samuel, et al.
(författare)
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Biochar amendment increases maize root surface areas and branching : a shovelomics study in Zambia
- 2015
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Ingår i: Plant and Soil. - : Springer Science and Business Media LLC. - 0032-079X .- 1573-5036. ; 395:1-2, s. 45-55
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Tidskriftsartikel (refereegranskat)abstract
- Positive crop yield effects from biochar are likely explained by chemical, physical and/or biological factors. However, studies describing plant allometric changes are scarcer, but may be crucial to understand the biochar effect. The main aim of the present study is to investigate the effect of biochar on root architecture under field conditions in a tropical setting. The presented work describes a shovelomics (i.e., description of root traits in the field) study on the effect of biochar on maize root architecture. Four field experiments we carried out at two different locations in Zambia, exhibiting non-fertile to relatively fertile soils. Roots of maize crop (Zea mays L.) were sampled from treatments with fertilizer (control) and with a combination of fertilizer and 4 t.ha(-1) maize biochar application incorporated in the soil. For the four sites, the average grain yield increase upon biochar addition was 45 +/- 14 % relative to the fertilized control (from 2.1-6.0 to 3.1-9.1 ton ha(-1)). The root biomass was approximately twice as large for biochar-amended plots. More extensive root systems (especially characterized by a larger root opening angle (+14 +/- 11 %) and wider root systems (+20 +/- 15 %)) were observed at all biochar-amended sites. Root systems exhibited significantly higher specific surface areas (+54 +/- 14 %), branching and fine roots: +70 +/- 56 %) in the presence of biochar. Biochar amendment resulted in more developed root systems and larger yields. The more extensive root systems may have contributed to the observed yield increases, e.g., by improving immobile nutrients uptake in soils that are unfertile or in areas with prolonged dry spells.
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| 2. |
- Kupryianchyk, Darya, et al.
(författare)
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Sorption of hydrophobic organic compounds to a diverse suite of carbonaceous materials with emphasis on biochar
- 2016
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Ingår i: Chemosphere. - : Elsevier. - 0045-6535 .- 1879-1298. ; 144, s. 879-887
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Tidskriftsartikel (refereegranskat)abstract
- Carbonaceous materials like biochars are increasingly recognized as effective sorbent materials for sequestering organic pollutants. Here, we study sorption behavior of two common hydrophobic organic contaminants 2,2',5,5'-tetrachlorobiphenyl (CB52) and phenanthrene (PHE), on biochars and other carbonaceous materials (CM) produced at a wide range of conditions and temperatures from various feedstocks. The primary aim was to establish structure–reactivity relationships responsible for the observed variation in CM and biochar sorption characteristics. CM were characterized for their elemental composition, surface area, pore size distribution, aromaticity and thermal stability. Freundlich sorption coefficients for CB52 and PHE (i.e. LogKF,CB52 and KF,PHE, respectively) to CM showed a variation of two to three orders of magnitude, with LogKF,CB52 ranging from 5.12 ± 0.38 to 8.01 ± 0.18 and LogKF,PHE from 5.18 ± 0.09 to 7.42 ± 1.09. The highest LogKF values were observed for the activated CM, however, non-activated biochars produced at high temperatures (>700 °C) sorbed almost as strongly (within 0.2–0.5 Log units) as the activated ones. Sorption coefficients significantly increased with pyrolysis temperature, CM surface area and pore volume, aromaticity, and thermal stability, and decreased with H/C, O/C, (O + N)/C content. The results of our study contribute to the understanding of processes underlying HOC sorption to CM and explore the potential of CM as engineered sorbents for environmental applications.
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| 3. |
- Le Noë, Julia, et al.
(författare)
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Soil organic carbon models need independent time-series validation for reliable prediction
- 2023
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Ingår i: Communications Earth & Environment. - 2662-4435. ; 4:1
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Tidskriftsartikel (refereegranskat)abstract
- Numerical models are crucial to understand and/or predict past and future soil organic carbon dynamics. For those models aiming at prediction, validation is a critical step to gain confidence in projections. With a comprehensive review of ~250 models, we assess how models are validated depending on their objectives and features, discuss how validation of predictive models can be improved. We find a critical lack of independent validation using observed time series. Conducting such validations should be a priority to improve the model reliability. Approximately 60% of the models we analysed are not designed for predictions, but rather for conceptual understanding of soil processes. These models provide important insights by identifying key processes and alternative formalisms that can be relevant for predictive models. We argue that combining independent validation based on observed time series and improved information flow between predictive and conceptual models will increase reliability in predictions.
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| 4. |
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| 5. |
- Wiedemeier, Daniel B., et al.
(författare)
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Characterization, Quantification and Compound-specific Isotopic Analysis of Pyrogenic Carbon Using Benzene Polycarboxylic Acids (BPCA)
- 2016
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Ingår i: Journal of Visualized Experiments. - : MyJove Corporation. - 1940-087X. ; :111
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Tidskriftsartikel (refereegranskat)abstract
- Fire-derived, pyrogenic carbon (PyC), sometimes called black carbon (BC), is the carbonaceous solid residue of biomass and fossil fuel combustion, such as char and soot. PyC is ubiquitous in the environment due to its long persistence, and its abundance might even increase with the projected increase in global wildfire activity and the continued burning of fossil fuel. PyC is also increasingly produced from the industrial pyrolysis of organic wastes, which yields charred soil amendments (biochar). Moreover, the emergence of nanotechnology may also result in the release of PyC-like compounds to the environment. It is thus a high priority to reliably detect, characterize and quantify these charred materials in order to investigate their environmental properties and to understand their role in the carbon cycle. Here, we present the benzene polycarboxylic acid (BPCA) method, which allows the simultaneous assessment of PyC's characteristics, quantity and isotopic composition (C-13 and C-14) on a molecular level. The method is applicable to a very wide range of environmental sample materials and detects PyC over a broad range of the combustion continuum, i.e., it is sensitive to slightly charred biomass as well as high temperature chars and soot. The BPCA protocol presented here is simple to employ, highly reproducible, as well as easily extendable and modifiable to specific requirements. It thus provides a versatile tool for the investigation of PyC in various disciplines, ranging from archeology and environmental forensics to biochar and carbon cycling research.
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