Glory and misery of biochar
Josef Maroušek, Marek Vochozka, Jan Plachý & Jaroslav Žák
Clean Technologies and Environmental Policy Focusing on Technology Research, Innovation, Demonstration, Insights and Policy Issues for Sustainable Technologies ISSN 1618-954X Clean Techn Environ Policy DOI 10.1007/s10098-016-1284-y
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Author's personal copy Clean Techn Environ Policy DOI 10.1007/s10098-016-1284-y
REVIEW
Glory and misery of biochar Josef Marousˇek1 • Marek Vochozka1 • Jan Plachy´1 • Jaroslav Zˇa´k1
Received: 4 May 2016 / Accepted: 19 September 2016 Ó Springer-Verlag Berlin Heidelberg 2016
Abstract Biochar refers to carbon-based dusty residues obtained from biomass pyrolysis. This recently rediscovered traditional soil improver is currently being glorified for its wide portfolio of favorable environmental aspects. With its lifetime of several centuries, it is being widely accepted as a promising method of carbon sequestration. Moreover, it has been demonstrated that biochar can reduce bioavailability of some heavy metals and that it has a high adsorption capacity to persistent organic pollutants. These effects are explained by a complex of physical, chemical and biological mechanisms. Besides agriculture, it has been currently used in food and chemical industries, as well as in the building industry. Many other promising applications are under investigation. However, contrary to many enthusiastic proclamations, no revolution in agriculture or environmental management is taking place. Despite significant achievements in reduction of biochar production costs, high demand from the industry and energy sector keeps the biochar price still high, which prevents a return of the ancient farming practice on a commercial scale. Keywords Soil management Environmental policy Technology transfer Agriculture Bioeconomy
Rediscovery of soil improver Biochar is a carbonaceous porous material obtained by pyrolysis of biomass, which is capable of absorbing and retaining plant nutrients in soil and thus improving soil & Josef Marousˇek
[email protected] 1
The Institute of Technology and Businesses in Cˇeske´ Budeˇjovice, Okruzˇnı´ 517/10, Cˇeske´ Budeˇjovice 370 01, Czech Republic
fertility (Lehmann 2007a). Its incorporation into topsoil is an ancient practice for soil structure improvement. Biochar has become the subject matter of intense research thanks to a book written by Joseph and Lehmann (2009) who summarized the current state of knowledge and highlighted biochar’s environmental potential. Since then almost all potential feedstock (farming and forest residues, food waste, paper waste, sewage sludge etc.), process parameters (biochemical pretreatment, particle size, temperature dynamics, hydraulic retention time, maximum temperature etc.) and other technoeconomic and environmental aspects (lignin content, heavy metals, persistent organic pollutants etc.) have been investigated (Zhao et al. 2013) and repeatedly reviewed (Ameloot et al. 2013) as a result of the wave of interest. A large number of laboratory pot experiments (Sohi et al. 2010) and field trials (Marousˇek 2014a, b) independently proved increased yields of many kinds of crops, as well as increase in soil quality indicators. However, the overall results from field trials with pure, untreated biochar are somewhat different from traditional practices where biochar was mixed with manure, human feces, food waste and agricultural residues to increase agricultural yields in poor soils (Ogawa and Okimori 2010). According to Joseph et al. (2010), interactions between biochar, soil, microbes and plant roots may occur within a short period. Bailey et al. (2011) claimed significant changes in soil enzymes (b-glucosidase, b-N-acetylglucosaminidase, lipase and leucine aminopeptidase) within 7 days. Possible reactions that may occur after biochar incorporation into soil include dissolution–precipitation, adsorption–desorption, acid–base and redox reactions. It has been also repeatedly demonstrated that biochar might increase pH, cation exchange capacity (CEC) and electrical conductivity, which all together significantly contribute to the overall soil fertility (Sohi et al. 2010). It
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should be also pointed out that the overall interactions seem to be sensitive to charring technology setup, i.e., to all the process parameters and to the nature of organic feedstock from which the biochar is produced. The overall agricultural and financial effects are definitely also dependent on the soil and the plant. Research conducted up to now has more or less confirmed that all interactions of biochar and topsoil are affected by physical, chemical and biological factors (Marousˇek et al. 2015a, b).
Physical properties Regarding the physical properties, the dusty and porous nature of biochar primarily affects water and air management of topsoil. It has been observed that the bulk density decreases, water holding capacity increases, and permeability is accelerated (Asai et al. 2009). Biochar has much lower bulk density than mineral soils, and therefore, application of biochar can reduce the overall bulk density of soil (Verheijen et al. 2010). When applying 100 t ha-1 of biochar with the bulk density of 0.4 g cm-3 into the top 20 cm of soil with the bulk density of 1.3 g cm-3 and if the biochar particles do not fill up the existing soil pore space, then the soil surface in that field will be raised by ca. 2.5 cm with the overall bulk density reduction (assuming homogeneous mixing) of 0.1–1.2 g cm-3. Smetanova´ et al. (2013), in good agreement with the mentioned example, observed that wettability of soil with incorporated biochar increased and its erodibility decreased. Other findings indicate that water retention of soil enriched with biochar is determined by distribution and connectivity of pores in the soil, which strongly depend on the size of soil particles (texture) in combination with structural characteristics (aggregation) and content of organic matter in the soil (Verheijen et al. 2010). Tseng and Tsen (2006) found that activated biochar contained over 95 % of micropores with the diameter \2 nm. Since porosity of biochar largely consists of micropores, the actual amount of additional water available for plants will depend on the biochar feedstock and on the soil texture. The agronomic benefits of biochar application (water-storage) will thus depend on the relative modification of the ratio of micro-, meso- and macropores in the root zone. Moreover, carbonaceous dark biochar makes the topsoil absorb more solar energy, which results in higher soil temperatures (Krull et al. 2004) causing higher activity of soil biota (Paul 2014) and, consequently, a longer vegetation period (Marousˇek et al. 2015a, b). Studies suggest that it is the mili-, micro- and nanoporosity (average particle size, surface area, specific volume, pore size distribution etc.) that considerably defines most of the biochar’s physical properties. Evidence suggests that biochar application into soil may increase the
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overall net soil surface area (Chan et al. 2007) and act as a perfect substrate for different soil micro flora and microanimalia. Biochar has a relatively structured carbon matrix with high degree of porosity and extensive surface area, suggesting that it may act as a surface sorbent which is similar in some aspects to activated carbon and thereby play an important role in controlling contaminants in the environment (Chen et al. 2011). The physical properties, especially the surface area of the biochar, are greatly affected by the temperature dynamics during the pyrolysis process. Process parameters also have an influence on the chemical properties, which limit the potential use for biochar products (Sohi et al. 2009). The results of Jiang et al. (2012) suggested possible interconnection of the physical properties with CEC and shift of the zeta potential–pH curves.
Chemical properties When discussing chemical properties of biochar, it should be noted that biochar is known to increase CEC and pH (Steiner et al. 2007). Aged biochar generally has high CEC, which increases its potential to act as a binding agent for organic matter and minerals (Verheijen et al. 2010). However, it is not currently known how biochar CEC will change as the biochar disintegrates by weathering and tillage operations, by ‘aging’ and moves through the soil. Elevated CEC is caused by increases in charge density per unit surface of organic matter, which equates with a greater degree of oxidation, or by increases in surface area for cation adsorption, or a combination of both (Atkinson et al. 2010). This is likely because of the removal of H– and O– carrying functional groups, including aliphatic alkyl–CH2, ester C5O, aromatic –CO and phenolic –OH groups, in biochars produced at 600 °C, greatly enlarged their surface areas (Chen et al. 2008). Much work has been done on plant residue or agricultural wastes-derived biochar for sorbing organic pollutants; however, only limited information is available on metal sorption as well as the associated underlying mechanisms (Chen et al. 2011). While biochars from wood/bark, dairy manure, broiler litter and biochars prepared from hydrothermal liquefaction of pinewood and rice husk have been shown to sorb significant amounts of heavy metals (such as As, Cd, Pb and Ni), there is very limited research on the effects of different biochars on Cu(II) and Zn(II) adsorption processes. The electric conductivity increases significantly with the higher pyrolysis temperature (Gai et al. 2014) which allows to estimate that the amount of total dissolved salts or the total amount of dissolved ions increases. Sorption to biochar is determined by the relative carbonized and non-carbonized fractions and their surface and
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bulk properties (Chen and Chen 2009). Biochar demonstrates 10–1000 times stronger affinity to organic compounds than natural organic matter, and it serves as a supersorbent. Moreover, decrease in atomic ratios H/C and O/C resulted from removing H– and O– containing functional groups with increasing temperature will produce high aromaticity and low polarity biochars (Gai et al. 2014). Yang and Sheng (2003) reported high sorption of pesticides. Chen and Chen (2009) showed that addition of biochar into soil improved the ability of sorption of polycyclic aromatic hydrocarbons (naphthalene, phenanthrene and pyrene). Other researchers observed immobilization of chlorine and organic chemicals, such as phenols, polychlorinated biphenyls, trihalomethanes, pentachlorophenol and halogenated hydrocarbons (Rhodes et al. 2008). The results of Park et al. (2011) clearly showed that biochar application was also effective in metal immobilization. Metal sequential fractionation data indicated that biochar treatments substantially modified partitioning of Cd, Cu and Pb from the easily exchangeable phase to less bioavailable organic bound fraction, thereby reducing bioavailability and phytotoxicity of heavy metals. Xue et al. (2012) claimed that this effect might be enhanced by activation of biochar with H2O2. Uchimiya et al. (2011) showed that biochar’s ability to sorb heavy metals depends on its production parameters. Spokas et al. (2010) formulated a hypothesis that the increase in root density, crop growth and overall plant yields that have been observed following biochar additions into soil is related to the release of C2H4, which is an important plant hormone, as well as an inhibitor for soil microbial processes. Xu et al. (2014) proved that biochar affected P availability by interaction with other organic and inorganic components in soil, such as organic matter or other base cations in the soil. Capture and delivery of nitrate and phosphate anions were proved by Kammann et al. (2015). Verheijen et al. (2010) summarized that biochar application into soil by itself may improve nutrient retention directly, but nutrient release is in most cases very small (except for some biochars in the first years, especially in ash-rich biochars).
Biological aspects Regarding the interactions with soil biota, these aspects are explained by an increased specific surface area of the soil, which brings benefits to native microbial communities. Fine biochar structures can provide refugia for beneficial soil microorganisms, such as mycorrhizae and bacteria, and they influence binding of important nutritive cations and anions (Atkinson et al. 2010). The function of biological communities in soils is complex, with its varied inhabitants classified as algae, archaea, arthropods, bacteria, fungi,
nematodes, protozoa and other invertebrates. For example, presence of heterotrophic phosphate-solubilizing microorganisms was enhanced after addition of biochar (Kimura and Nishio 1989). Different functional groups within ‘soil fungi’, i.e., saprophytes, pathogens and mycorrhizae, respond differently to biochar application (Thies and Rillig 2009). Biochar increases basal respiration and microbial efficiency, and there is experimental evidence that biochar addition into soil increases N2 fixation by both free living and symbiotic diazotrophs (Rondon et al. 2007). Biochar provides microbial habitat and refugia for microbes whereby they are protected from grazing (Verheijen et al. 2010). Moreover, biochar also increases mycorrhizal abundance, which is linked to the observed increases in plant yields. This is possibly due to: (a) alteration of soil physicochemical properties, (b) indirect effects on mycorrhizae through effects on other soil microbes, (c) plant-fungus signaling interference and detoxification of allelochemicals on biochar or (d) provision of refugia from fungal grazers. Besides physical and chemical stabilization mechanisms, another important factor that may affect the residence time of biochar in soils is the phenomenon of co-metabolism (Verheijen et al. 2010). This is where biochar decomposition is increased due to microbial metabolism of other substrates, which is often increased when soil organic matter is ‘unlocked’ from the soil structure due to disturbance (e.g., incorporating biochar into the soil via tillage). Degradation by microbially produced exoenzymes is faster with better intrasurface accessibility (Zimmerman 2010). The increased microbial biomass and decreased basal respiration suggest that biochar may increase efficiency of microbial carbon use (Jin 2010). This effect could be partly explained by changes in microbial community composition and, probably, also by an increased ratio of fungal to bacterial biomass in soils with high content of biochar. Results have shown that soils with biochar had 615.3 and 15.0 % higher activities of alkaline phosphatase and aminopeptidase, respectively, but 81.3 and 82.2 % lower activities of b-D-glucosidase, b-D-cellobiase, respectively. Those changes in enzyme activities suggest that P and N use is increased in relation to C mineralized in response to biochar addition. The decreased activity of C mineralizing enzymes probably contributes to the stability of labile C in soils containing biochar. The increased need for microbial P and N acquisition relative to C in response to biochar application suggests a shift in microbial community composition in soils containing biochar, while one such possibility is an increase in the presence of arbuscular mycorrhizal fungus that forms mutualistic symbioses with plant roots and metabolizes C from their hosts in exchange for other nutrient elements, such as N and P from soil. Cloning and sequencing of the fungal internal transcribed spacer region from community DNA extracted from biochar-amended soil samples revealed presence of a complex
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fungal community. Bailey et al. (2011) state that, except for b-N-acetylglucosaminidase, the exposure of soil biota to biochar reduced apparent activity of soil enzymes, suggesting that sorption reactions between substrate and biochar impeded enzyme function. The effects of biochar on enzyme activities in soils are highly variable, and those effects are probably associated with reactions between biochar and the target soil biota. At last but not least, from the ‘macrobiological’ point of view, incorporation of biochar into the topsoil (Hasˇkova´ 2016) or composts (Marousˇek et al. 2016) represents long-term locking of carbon (Lehmann 2007b) that was previously captured by plants during the photosynthesis.
Waste management The above-described properties of biochar make it also a promising object of research in waste management. Conversion of biodegradable biowaste into biochar is now considered one of favorable recycling options (Cao and Harris 2010). Inyang et al. (2012) claim that biochar can effectively remove heavy metals from aqueous solutions, and thus it can be used as an alternative sorbent for activated carbon or other water purifiers to treat heavy metals in wastewater. Ahmad et al. (2014) reminds that solid waste material, such as animal litter and sewage sludge, could be freed from all active pathogens through conversion to biochar and that volatiles and gases released during biochar production can be captured and condensed into biooil and syngas and further used as a source of renewable energy. Results of Jones et al. (2012) suggest that biochar application into soil seems to shift the microbial decomposer community toward a bacterial dominated one, which was accompanied by lower microbial growth efficiency in biochar than in untreated soil. According to Verheijen et al. (2010), there is enough evidence that it is possible to use biochar’s sorptive capacity in water and wastewater treatments, by using activated carbon for removal of chlorine and halogenated hydrocarbons, organic compounds (e.g., phenols, polychlorinated biphenyls, pesticides etc.). Bamboo biochar powder proved to be effective in removal of nitrates from drinking water (Mizuta et al. 2004). Other studies in aqueous media, as reviewed by Radovic et al. (2001), reported that biochar’s capacity to adsorb PO4 and NH4. Laird (2008) states that biochar could reduce leaching of pesticides and nutrients into surface and ground water. Hossain et al. (2011) found that higher pyrolysis temperatures might increase concentration of heavy metals (Zn, Pb, Ni and Cd) in pyrolyzed sewage sludge, which is important as the heavy metals can bioaccumulate when biochar is applied to the soil. However, those elements were found to become less available to plants. Kammann et al. (2015)
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have proved that biochar improves quality of composts. This finding is in good agreement with Marousˇek et al. (2015a, b) who considered composting with biochar a promising alternative for utilization of poorly biodegradable waste from the food industry, which had been previously exposed to anaerobic fermentation. Subsequent increase in biochar quality might be carried out by increase in the porosity that is routinely called ‘activation’. The activation processes are traditionally being divided into physical (steam, shockwave, Marousˇek 2013) and chemical (alkaline hydroxydes, Azargohar and Dalai 2008). The key process parameters also include activation temperature, activating agent, biochar mass ratio and the amount of O2. In particular, higher CEC of activated biochars may promote retention of ammonium (Ding et al. 2010), which later can be nitrified. Borchard et al. (2012) reported no advantage regarding the plant yields; however, the activation reduced leaching losses of inorganic P and in silty soil also of N. Nutrient availability to plants is also increased; however, the cost of activation seems to be unreasonably high in comparison with the above-mentioned advantages (Marousˇek et al. 2012). Therefore, the use for activated biochar will be hardly profitable in conventional agriculture, but rather in food or chemical engineering or waste management to reduce organic contaminants (Beesley et al. 2011) or heavy metals bioavailability.
Economy and policy Two barriers to practical application of biochar have been repeatedly mentioned in the literature (Jones et al. 2012): the lack of commercial biochar available to farmers and, most importantly, legislative barriers that prevent its application in soil (e.g., in Europe). Regarding the legislative barriers, it should be noted that a case study from Liberia reported by Leach et al. (2012) illustrates how absence of regulation and free market resulted in quick development of biochar farming. On the other hand, Jones et al. (2012) stated that in the developed countries the failure to include biochar into the current agricultural policy is due to the major uncertainty surrounding the longterm behavior of biochar, its potential negative impacts on soil quality and the fact that it practically cannot be removed from soil after its application. In addition, the current price of approximately 250 USDApril2015 t-1 makes biochar hardly profitable in conventional farming (Mardoyan and Braun 2015). Williams and Arnott (2010) anticipated that innovative application methods, not yet developed or tested at that time could, in the future, substantially decrease costs through implementation of specifically designed and optimized technology. The expected technological breakthrough actually came several
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years later (Marousˇek 2015a, b), however, not even the reduction in the production costs close to zero affected the price on the market. A review by Ahmad et al. (2014) indicated that activated biochar could replace activated carbon as it has equivalent or even greater sorption efficiency for various contaminants. In agreement with McCarl et al. (2009), the estimated break-even price for biochar is 246 USD t-1, which is approximately 1/6th of commercially available activated carbon (1500 USD t-1). Discussions conducted by Jones et al. (2012) with regional farmers suggested that biochar availability and particularly economic costs were the greatest barriers to the use of biochar (Marousˇkova´ and Braun 2014), although practical aspects (e.g., wind erosion during spreading and risk of human inhalation) were also perceived as negative consequences. Generally, farmers were little concerned about the impact of biochar on soil quality, as long as biochar proved to have a low content of heavy metals. This largely reflects the current attitudes of farmers to the application of waste on the land. A robust meta-analysis of the relationship between biochar and crop yields, carried out by Jeffery et al. (2011), has shown an overall positive effect of approximately 10 % on crop yields with high statistical significance. Such a result is economically robust and useful as it provides a sound basis for potential benefits of biochar application in respect to crop yields. The greatest positive effects were seen in biochar application rates of 100 t ha-1 (39 %). Other positive effects were seen in acidic (14 %) and neutral pH soils (13 %) and in soils with coarse (10 %) or medium texture (13 %). Finally, yet importantly, the liming effect and the influence on the water holding capacity of soil should be mentioned although the economic evaluation is even more problematic. Findings of Slavich et al. (2013) can be interpreted in such a way that alkali forms of biochar can fully substitute liming. Based on ideas of Vanholme et al. (2013), it would be financially beneficial to incorporate biochar production into a biorefinery concept. Laird (2008) estimated that biochar production would generate significant amounts of biooil and pyrolytic gas that could reduce global consumption of fossil fuels. From the economical point of view, it is important that biochar may remain stable in soil for many hundreds of years (Lehmann 2007a, b); however, Jones et al. (2012) claim that the lack of negative effects seen at application rates of either 25 or 50 t ha-1 also suggests that repeated applications of biochar may be possible. The mechanical stability and recalcitrance of biochar after its incorporation into the soil will determine long-term effects on water retention and soil structure (Verheijen et al. 2010). This is determined by the type of feedstock and operating conditions, as well as by prevalent physicochemical conditions that determine its weathering. On the other hand, biochar can prevent the action of
preemergent herbicides (Lehmann et al. 2011), all of which would be perceived as negative outcomes. Regarding the use of biochar in conventional agriculture, case studies supported by financial assessments indicate that the current pricing of biochar leads to investment payback periods in dozens of years (Marousˇek et al. 2015a, b).
Outlook and conclusions For the first time, review on biochar farming in a commercial scale was carried out. The review indicates that biochar’s improving effects on the structure of soils (water and air management of the topsoil) and on activity of soil biota and plant–soil interactions that subsequently result in increased crop yields can be considered proved as they have been repeatedly and independently confirmed. It has been concluded that those phenomena might be explained by complex interactions between the physical, chemical and biological characteristics. The role of phytohormone C2H2 spontaneously released from biochar and its subsequent interactions with plants and soil biota cannot yet be considered as explained. Biochar has the potential to reduce bioaccessibility of various persistent organic contaminants and some heavy metals as well. It seems that it is the biochar’s sorptive capacity that is responsible for locking of long molecules of organic contaminants. Heavy metals are very likely to be immobilized during the pyrolysis process when they change from chlorides and sulfates into steady oxides, preferably silicates. Despite the ongoing research and significant reduction in costs of biochar production, the high demand driven by alternative applications in the industry and energy sector keeps price of biochar too high to make its application profitable in conventional farming. It is expected that the increasing pressure on cost reduction will result in a change in the feedstock and that the wood will be replaced with fermentation residues and other poorly biodegradable waste. However, such a reduction in price will also mean reduction in its many quality indicators. Based on the facts described above, it seems that commercial application of biochar in near future will focus on other fields of the industry, such as building materials or waste management, and biochar will play an increased role in nutrient-reuse technologies. Acknowledgments Authors acknowledge the support provided by the Quality Innovation of the Year 2014 award.
References Ahmad M, Rajapaksha AU, Lim JE, Zhang M, Bolan N, Mohan D, Vithanage M, Lee SS, Ok YS (2014) Biochar as a sorbent for
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Author's personal copy J. Marousˇek et al. contaminant management in soil and water: a review. Chemosphere 99:19–33 Ameloot N, Graber ER, Verheijen FG, De Neve S (2013) Interactions between biochar stability and soil organisms: review and research needs. Eur J Soil Sci 64:379–390 Asai H, Samson BK, Stephan HM, Songyikhangsuthor K, Homma K, Kiyono Y, Inoue Y, Shiraiwa T, Horie T (2009) Biochar amendment techniques for upland rice production in Northern Laos: 1. Soil physical properties, leaf SPAD and grain yield. Field Crops Res 111:81–84 Atkinson CJ, Fitzgerald JD, Hipps NA (2010) Potential mechanisms for achieving agricultural benefits from biochar application to temperate soils: a review. Plant Soil 337:1–18 Azargohar R, Dalai AK (2008) Steam and KOH activation of biochar: experimental and modeling studies. Microporous Mesoporous Mater 110:413–421 Bailey VL, Fansler SJ, Smith JL, Bolton H (2011) Reconciling apparent variability in effects of biochar amendment on soil enzyme activities by assay optimization. Soil Biol Biochem 43:296–301 Beesley L, Moreno-Jime´nez E, Gomez-Eyles JL, Harris E, Robinson B, Sizmur T (2011) A review of biochars’ potential role in the remediation, revegetation and restoration of contaminated soils. Environ Pollut 159:3269–3282 Borchard N, Wolf A, Laabs V, Aeckersberg R, Scherer HW, Moeller A, Amelung W (2012) Physical activation of biochar and its meaning for soil fertility and nutrient leaching—a greenhouse experiment. Soil Use Manag 28:177–184 Cao X, Harris W (2010) Properties of dairy-manure-derived biochar pertinent to its potential use in remediation. Bioresour Technol 101:5222–5228 Chan KY, Van Zwieten L, Meszaros I, Downie A, Joseph S (2007) Assessing the agronomic values of contrasting char materials on Australian hardsetting soil. In: Proceedings of the conference of the international agrichar initiative, Terrigal, NSW, Australia Chen B, Chen Z (2009) Sorption of naphthalene and 1–naphthol by biochars of orange peels with different pyrolytic temperatures. Chemosphere 76:127–133 Chen B, Zhou D, Zhu L (2008) Transitional adsorption and partition of nonpolar and polar aromatic contaminants by biochars of pine needles with different pyrolytic temperatures. Environ Sci Technol 42:5137–5143 Chen X, Chen G, Chen L, Chen Y, Lehmann J, McBride MB, Hay AG (2011) Adsorption of copper and zinc by biochars produced from pyrolysis of hardwood and corn straw in aqueous solution. Bioresour Technol 102:8877–8884 Ding Y, Liu Y-X, Wu W-X, Shi D-Z, Yang M, Zhong Z-K (2010) Evaluation of biochar effects on nitrogen retention and leaching in multi-layered soil columns. Water Air Soil Pollut 213:47–55 Gai X, Wang H, Liu J, Zhai L, Liu S, Ren T, Liu H (2014) Effects of feedstock and pyrolysis temperature on biochar adsorption of ammonium and nitrate. PLoS ONE 9:e113888 Hasˇkova´ S (2016) Holistic Assessment and Ethical Disputation on a New Trend in Solid Biofuels. Sci Eng Ethics. doi:10.1007/ s11948-016-9790-1 Hossain MK, Strezov V, Chan KY, Ziolkowski A, Nelson PF (2011) Influence of pyrolysis temperature on production and nutrient properties of wastewater sludge biochar. J Environ Manag 92:223–228 Inyang M, Gao B, Yao Y, Xue Y, Zimmerman AR, Pullammanappallil P, Cao X (2012) Removal of heavy metals from aqueous solution by biochars derived from anaerobically digested biomass. Bioresour Technol 110:50–56 Jeffery S, Verheijen FGA, Van Der Velde M, Bastos AC (2011) A quantitative review of the effects of biochar application to soils
123
on crop productivity using meta–analysis. Agric Ecosyst Environ 144:175–187 Jiang TY, Jiang J, Xu RK, Li Z (2012) Adsorption of Pb (II) on variable charge soils amended with rice-straw derived biochar. Chemosphere 89:249–256 Jin H (2010) Characterization of microbial life colonizing biochar and biochar-amended soils. Dissertation, Faculty of the Graduate School of Cornell University Jones DL, Rousk J, Edwards-Jones G, DeLuca TH, Murphy DV (2012) Biochar-mediated changes in soil quality and plant growth in a three year field trial. Soil Biol Biochem 45:113–124 Joseph S, Lehmann J (2009) Biochar for environmental management: science and technology. Earthscan, London, GB Joseph SD et al (2010) An investigation into the reactions of biochar in soil. Soil Res 48:501–515 Kammann CI, Schmidt HP, Messerschmidt N, Linsel S, Steffens D, Mu¨ller C, Kyoro H-W, Conte P, Joseph S (2015) Plant growth improvement mediated by nitrate capture in co-composted biochar. Sci Rep 5:11080 Kimura R, Nishio M (1989) Contribution of soil microorganisms to utilization of insoluble soil phosphorus by plants in grasslands. In: Third grassland ecology conference, Czechoslovakia, pp 10–17 Krull ES, Skjemstad JO, Baldock JA (2004) Functions of soil organic matter and the effect on soil properties. In: Cooperative Research Centre for Greenhouse Accounting. CSIRO Land & Water, Glen Osmond Laird DA (2008) The charcoal vision: a win–win–win scenario for simultaneously producing bioenergy, permanently sequestering carbon, while improving soil and water quality. Agron J 100:178–181 Leach M, Fairhead J, Fraser J (2012) Green grabs and biochar: revaluing African soils and farming in the new carbon economy. J Peasant Stud 39:285–307 Lehmann J (2007a) Bio-energy in the black. Front Ecol Environ 5:381–387 Lehmann J (2007b) A handful of carbon. Nature 447:143–144 Lehmann J, Rillig MC, Thies J, Masiello CA, Hockaday WC, Crowley D (2011) Biochar effects on soil biota–a review. Soil Biol Biochem 43:1812–1836 Mardoyan A, Braun P (2015) Analysis of Czech subsidies for solid biofuels. Int J Green Energy 12:405–408 Marousˇek J (2013) Use of continuous pressure shockwaves apparatus in rapeseed oil processing. Clean Technol Environ Policy 15:721–725 Marousˇek J (2014a) Economically oriented process optimization in waste management. Environ Sci Pollut Res 21:7400–7402 Marousˇek J (2014b) Significant breakthrough in biochar cost reduction. Clean Technol Environ Policy 16:1821–1825 Marousˇek J, Kawamitsu Y, Ueno M, Kondo Y, Kola´rˇ L (2012) Methods for improving methane yield from rye straw. Appl Eng Agric 28:747–755 Marousˇek J, Hasˇkova´ S, Zeman R, Vanı´cˇkova´ R (2015a) Managerial preferences in relation to financial indicators regarding the mitigation of global change. Sci Eng Ethics 21:203–207 Marousˇek J, Hasˇkova´ S, Zeman R, Zˇa´k J, Vanı´cˇkova´ R, Marousˇkova´ A, Va´chal J, Mysˇkova´ K (2015b) Techno-economic assessment of processing the cellulose casings waste. Clean Technol Environ Policy 17:2441–2446 Marousˇek J, Hasˇkova´ S, Zeman R, Zˇa´k J, Vanı´cˇkova´ R, Marousˇkova´ A, Va´chal J, Mysˇkova´ K (2016) Polemics on ethical aspects in the compost business. Sci Eng Ethics 22:581–590 Marousˇkova´ A, Braun P (2014) Holistic approach to improve the energy utilization of Jatropha curcas L. Rev Te´c Ing Univ Zulia 37:144–150
Author's personal copy Glory and misery of biochar McCarl BA, Peacocke C, Chrisman R, Kung CC, Sands RD (2009) Economics of biochar production, utilization and greenhouse gas offsets. Biochar for environmental management: science and technology. Earthscan, London, Washington D.C, pp 341–358 Mizuta K, Matsumoto T, Hatate Y, Nishihara K, Nakanishi T (2004) Removal of nitrate–nitrogen from drinking water using bamboo powder charcoal. Bioresour Technol 95:255–257 Ogawa M, Okimori Y (2010) Pioneering works in biochar research, Japan. Soil Res 48:489–500 Park JH, Choppala GK, Bolan N, Chung JW, Chuasavathi T (2011) Biochar reduces the bioavailability and phytotoxicity of heavy metals. Plant Soil 348:439–451 Paul EA (2014) Soil microbiology, ecology and biochemistry, vol 4. Academic press, Elsevier, Amsterdam Radovic LR, Moreno-Castilla C, Rivera-Utrilla J (2001) Carbon materials as adsorbents in aqueous solutions. Chem Phys Carbon 27:227–405 Rhodes AH, Carlin A, Semple KT (2008) Impact of black carbon in the extraction and mineralization of phenanthrene in soil. Environ Sci Technol 42:740–745 Rondon MA, Lehmann J, Ramı´rez J, Hurtado M (2007) Biological nitrogen fixation by common beans (Phaseolus vulgaris L.) increases with bio–char additions. Biol Fertil Soils 43:699–708 Slavich PG, Sinclair K, Morris SG, Kimber SW, Downie A, Van Zwieten L (2013) Contrasting effects of manure and green waste biochars on the properties of an acidic ferralsol and productivity of a subtropical pasture. Plant Soil 366:213–227 Smetanova´ A, Dotterweich M, Diehl D, Ulrich U, Dotterweich NF (2013) Influence of biochar and terra preta substrates on wettability and erodibility of soils. Z Geomorphol Supp 57:111–134 Sohi S, Lopez-Capel E, Krull E, Bol R (2009) Biochar, climate change and soil: a review to guide future research. CSIRO Land Water Sci Rep 5:17–31 Sohi SP, Krull Lopez-Capel E, Bol R (2010) A review of biochar and its use and function in soil. Adv Agron 105:47–82 Spokas KA, Baker JM, Reicosky DC (2010) Ethylene: potential key for biochar amendment impacts. Plant Soil 333:443–452 Steiner C, Teixeira WG, Lehmann J, Nehls T, de Maceˆdo JLV, Blum WE, Zech W (2007) Long term effects of manure, charcoal and
mineral fertilization on crop production and fertility on a highly weathered Central Amazonian upland soil. Plant Soil 291:275–290 Thies JE, Rillig MC (2009) Characteristics of biochar: biological properties. Biochar for environmental management: science and technology. Earthscan, London, pp 86–105 Tseng RL, Tsen SK (2006) Characterization and use of high surface area activated carbons prepared from cane pith for liquid–phase adsorption. J Hazard Mater 136:671–680 Uchimiya M, Wartelle LH, Klasson KT, Fortier CA, Lima IM (2011) Influence of pyrolysis temperature on biochar property and function as a heavy metal sorbent in soil. J Agric Food Chem 59:2501–2510 Vanholme B, Desmet T, Ronsse F, Rabaey K, Van Breusegem F, De Mey M, Soetaert W, Boerjan W (2013) Towards a carbon– negative sustainable bio–based economy. Front Plant Sci 4:174 Verheijen F, Jeffery S, Bastos AC, Van der Velde M, Diafas I (2010) Biochar application to soils. Institute for Environment and Sustainability, Luxembourg Williams MM, Arnott JC (2010) A comparison of variable economic costs associated with two proposed biochar application methods. Ann Environ Sci 4:23–30 Xu G, Sun J, Shao H, Chang SX (2014) Biochar had effects on phosphorus sorption and desorption in three soils with differing acidity. Ecol Eng 62:54–60 Xue Y, Gao B, Yao Y, Inyang M, Zhang M, Zimmerman AR, Ro KS (2012) Hydrogen peroxide modification enhances the ability of biochar (hydrochar) produced from hydrothermal carbonization of peanut hull to remove aqueous heavy metals: batch and column tests. Chem Eng J 200:673–680 Yang Y, Sheng G (2003) Enhanced pesticide sorption by soils containing particulate matter from crop residue burns. Environ Sci Technol 37:3635–3639 Zhao L, Cao X, Masˇek O, Zimmerman A (2013) Heterogeneity of biochar properties as a function of feedstock sources and production temperatures. J Hazard Mater 256:1–9 Zimmerman AR (2010) Abiotic and microbial oxidation of laboratory–produced black carbon (biochar). Environ Sci Technol 44:1295–1301
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