Biochar application to agricultural soils is an interesting emerging technology with promising potential for long-term carbon storage, sustainable waste disposal, and soil fertility enhancement. Extensive information exists in the literature on the highly beneficial properties of biochar. Nevertheless, systematic application of biochar on European agricultural soils may have wide ranging policy implications as well as environmental and public health concerns. In this paper we critically review existing scientific evidence from a European policy perspective and identify research gaps for future comprehensive assessments of the policy, environmental, economic, and health implications of the systematic use of biochar in European agricultural soils.
References
[1]
International Biochar Initiative (IBI). Standardized Product Definition and Product Testing Guidelines for Biochar That Is Used in Soil; International Biochar Initiative: Westerville, HO, USA, 2012.
[2]
Sombroek, W.G. Amazon Soils: A Reconnaissance of the Soils of the Brazilian Amazon Region; Wageningen Center for Agriculture Publications and Documentation: Wageningen, The Netherlands, 1966.
[3]
Lehmann, J. Bio-energy in the black. Front. Ecol. Environ. 2007, 5, 381–387, doi:10.1890/1540-9295(2007)5[381:BITB]2.0.CO;2.
[4]
Manya, J.J. Pyrolysis for biochar purposes: A review to establish current knowledge gaps and research needs. Environ. Sci. Technol. 2012, 15, 7939–7954, doi:10.1021/es301029g.
[5]
Directive 2008/98/EC of the European Parliament and of the Council of 19 November 2008 on Waste and Repealing Certain Directives Text with EEA Relevance; European Commission: Brussels, Belgium, 2008.
[6]
Communication from the Commission to the Council, the European Parliament, the European Economic and Social Committee of the Regions, Thematic Strategy for Soil Protection. Brussels; European Commission: Brussels, Belgium, 2006.
[7]
Proposal for a Directive of the European Parliament and of the Council Establishing a Framework for the Protection of Soil and Amending Directive 2004/35/EC; European Commission: Brussels, Belgium, 2006.
[8]
Lehmann, J.; Gaunt, J.; Rondon, M. Biochar sequestration in terrestrial ecosystems. Mitig. Adapt. Strateg. Glob. Chang. 2006, 11, 315–419.
[9]
Atkinson, C.J.; Fitzgerald, J.D.; Hipps, N.A. Potential mechanisms for achieving agricultural benefits from biochar application to temperate soils: A review. Plant Soil 2010, 337, 1–18, doi:10.1007/s11104-010-0464-5.
[10]
Biederman, L.A.; Harpole, W.S. Biochar and its effects on plant productivity and nutrient cycling: A meta-analysis. GCB Bioenergy 2013, 5, 202–214, doi:10.1111/gcbb.12037.
[11]
Chan, K.Y.; Zwieten, V.L.; Meszaros, I.; Dowine, A.; Joseph, S. Using poultry litter biochars as soil amendments. Aust. J. Soil Res. 2008, 46, 437–444, doi:10.1071/SR08036.
[12]
Kookana, R.S.; Sarmah, A.K.; Van Zwieten, L.; Krull, E.; Singh, B. Biochar application to soil: Agronomic and environmental benefits and unintended consequences. Adv. Agron. 2011, 112, 103–143, doi:10.1016/B978-0-12-385538-1.00003-2.
[13]
Beesley, L.; Moreno-Jiménez, E.; Gomez-Eyles, J.L.; Harris, E.; Robinson, B.; Sizmur, T. A review of biochars’ potential role in the remediation, revegetation and restoration of contaminated soils. Environ. Pollut. 2011, 159, 3269–3282, doi:10.1016/j.envpol.2011.07.023.
[14]
Beesley, L.; Marmiroli, M. The immobilisation and retention of soluble arsenic, cadmium and zinc by biochar. Environ. Pollut. 2011, 159, 474–480, doi:10.1016/j.envpol.2010.10.016.
[15]
Farrell, M.; Rangott, G.; Krull, E. Difficulties in using soil-based methods to assess plant availability of potentially toxic elements in biochars and their feedstocks. J. Hazard Mater. 2013, 250–251, 29–36, doi:10.1016/j.jhazmat.2013.01.073.
[16]
Glaser, B. European biochar certification. State of the art and future challenges. In Proceedings of the 1st Mediterranean Biochar Symposium, Vetermate con Minoprio (CO), Italy, 17–18 January 2013.
[17]
Calvelo Pereira, R.; Kaal, J.; Camps Arbestain, M.; Pardo Lorenzo, R.; Aitkenhead, W.; Hedley, M.; Macías, F.; Hindmarsh, J.; Maciá-Agulló, J.A. Contribution to characterisation of biochar to estimate the labile fraction of carbon. Org. Geochem. 2011, 42, 1331–1342.
[18]
Quilliam, R.S.; Rangecroft, S.; Emmett, B.A. Is biochar a source or sink for polycyclic aromatic hydrocarbon (PAH) compounds in agricultural soils? GCB Bioenergy 2013, 96–103, doi:10.1111/gcbb.12007.
[19]
Gomez-Eyles, J.L.; Sizmur, T.; Collins, C.D.; Hodson, M.E. Effects of biochar and the earthworm Eisenia fetida on the bioavailability of polycyclic aromatic hydrocarbons and potentially toxic elements. Environ. Pollut. 2011, 159, 616–622, doi:10.1016/j.envpol.2010.09.037.
[20]
Li, D.; Hockaday, W.C.; Masiello, C.A.; Alvarez, P.J.J. Soil Biology & Biochemistry Earthworm avoidance of biochar can be mitigated by wetting. Soil Biol. Biochem. 2011, 43, 1732–1737, doi:10.1016/j.soilbio.2011.04.019.
[21]
Zhang, H.; Lin, K.; Wang, H.; Gan, J. Effect of Pinus radiata derived biochars on soil sorption and desorption of phenanthrene. Environ. Pollut. 2010, 158, 2821–2825, doi:10.1016/j.envpol.2010.06.025.
[22]
Jones, D.L.; Edwards-Jones, G.; Murphy, D.V. Biochar mediated alterations in herbicide breakdown and leaching in soil. Soil Biol. Biochem. 2011, 43, 804–813, doi:10.1016/j.soilbio.2010.12.015.
[23]
Nag, S.K.; Kookana, R.; Smith, L.; Krull, E.; Macdonald, L.M.; Gill, G. Poor efficacy of herbicides in biochar-amended soils as affected by their chemistry and mode of action. Chemosphere 2011, 84, 1572–1577, doi:10.1016/j.chemosphere.2011.05.052.
[24]
Larsbo, M.; L？fstrand, E.; Alphen, D.V.; Veer, D.; Ulén, B. Pesticide leaching from two Swedish topsoils of contrasting texture amended with biochar. J. Contam. Hydrol. 2013, 147, 73–81, doi:10.1016/j.jconhyd.2013.01.003.
[25]
Woolf, D.; Amonette, J.E.; Street-Perrott, F.A.; Lehmann, J.; Joseph, S. Sustainable biochar to mitigate global climate change. Nat. Commun. 2010, 1, doi:10.1038/ncomms1053.
[26]
Stavi, I. Biochar use in forestry and tree-based agro-ecosystems for increasing climate change mitigation and adaptation. Int. J. Sustain. Dev. World Ecol. 2013. in press.
Rutherford, D.W.; Wershaw, R.L.; Rostad, C.E.; Kelly, C.N. Effect of formation conditions on biochars: Compositional and structural properties of cellulose, lignin, and pine biochars. Biomass Bioenergy 2012, 46, 693–701.
[29]
Schimmelpfennig, S.; Glaser, B. One step forward toward characterization: Some important material properties to distinguish biochars. J. Environ. Qual. 2012, 41, 1001–1013, doi:10.2134/jeq2011.0146.
[30]
Stavi, I.; Lal, R. Agroforestry and biochar to offset climate change: A review. Agron. Sustain. Dev. 2013, 33, 81–96, doi:10.1007/s13593-012-0081-1.
[31]
Kuzyakov, Y.; Subbotina, I.; Chen, H.; Bogomolova, I.; Xu, X. Black carbon decomposition and incorporation into soil microbial biomass estimated by 14C labeling. Soil Biol. Biochem. 2009, 41, 210–219, doi:10.1016/j.soilbio.2008.10.016.
[32]
Cross, A.; Sohi, S.P. The priming potential of biochar products in relation to labile carbon contents and soil organic matter status. Soil Biol. Biochem. 2011, 43, 2127–2134, doi:10.1016/j.soilbio.2011.06.016.
[33]
Mc Henry, M. Agricultural bio-char production, renewable energy generation and farm carbon sequestration in Western Australia: Certainty, uncertainty and risk. Agric. Ecosyst. Environ. 2009, 129, 1–7, doi:10.1016/j.agee.2008.08.006.
[34]
Roberts, K.G.; Gloy, B.A.; Jodeph, S.; Scott, N.R.; Lehmann, J. Life Cycle Assessment of Biochar Systems: Estimating the Energetic, Economic, and Climate Change Potential. Environ. Sci. Technol. 2010, 44, 827–833, doi:10.1021/es902266r.
[35]
Ernsting, A.; Smolker, R.; Paul, H. Biochar and carbon markets. Biofuels 2011, 2, 9–12, doi:10.4155/bfs.10.78.
[36]
Supporting Environmentally Sound Decisions for Bio-Waste Management—A Practical Guide to Life Cycle Thinking (LCT) and Life Cycle Assessment (LCA); European Commission: Brussels, Belgium, 2011.
[37]
Chan, K.Y.; Zwieten, V.L.; Meszaros, I.; Dowine, A.; Joseph, S. Agronomic value of green waste biochar as a soil amendment. Aust. J. Soil Res. 2007, 45, 629–634, doi:10.1071/SR07109.
[38]
Marris, E. Putting the carbon back: Black is the new green. Nature 2006, 442, 624–626, doi:10.1038/442624a.
[39]
Wang, T.; Camps-Arbestain, M.; Hedley, M.; Bishop, P. Chemical and bioassay characterisation of nitrogen availability in biochar produced from dairy manure and biosolids. Org. Geochem. 2012, 51, 45–54.
[40]
Wang, T.; Camps-Arbestain, M.; Hedley, M.; Bishop, P. Predicting phosphorus bioavailability from high-ash biochars. Plant Soil 2012, 357, 173–187, doi:10.1007/s11104-012-1131-9.
[41]
Prost, K.; Borchard, N.; Siemens, J.; Kautz, T.; Séquaris, J.M.; M？ller, A.; Amelung, W. Biochar affected by composting with farmyard manure. J. Environ. Qual. 2013, 42, 164–172, doi:10.2134/jeq2012.0064.
[42]
Steiner, C.; Das, K.C.; Melear, N.; Lakly, D. Reducing nitrogen loss during poultry litter composting using biochar. J. Environ. Qual. 2010, 39, 1236–1242, doi:10.2134/jeq2009.0337.
[43]
Brewer, C.E.; Klaus, S.; Satrio, J.A.; Brown, R.C. Characterization of biochar from fast pyrolysis and gasification systems. Environ. Prog. Sustain. Energy 2009, 28, 386–396, doi:10.1002/ep.10378.
[44]
Zimmerman, A.R. Abiotic and microbial oxidation of laboratory produced black carbon (biochar). Environ. Sci. Technol. 2010, 44, 1295–1301, doi:10.1021/es903140c.
[45]
Meyer, S.; Glaser, B.; Quicker, P. Technical, economical, and climate-related aspects of biochar production technologies: A literature review. Environ. Sci. Technol. 2011, 45, 9473–9483, doi:10.1021/es201792c.
[46]
Hammond, J.; Shackley, S.; Sohi, S.; Brownsort, P. Prospective life cycle carbon abatement for pyrolysis biochar systems in the UK. Carbon 2011, 39, 2646–2655.
[47]
Lugato, E.; Vaccari, F.P.; Genesio, L.; Baronti, S.; Pozzi, A.; Rack, M.; Woods, J.; Simonetti, G.; Montanarella, L.; Miglietta, F. An energy-biochar chain involving biomass gasification and rice cultivation in Northern Italy. Glob. Chang. Bioenergy 2013, 5, 192–201.
[48]
Han, J.; Elgowainy, A.; Dunn, J.B.; Wang, M.Q. Life cycle analysis of fuel production from fast pyrolysis of biomass. Bioresour. Technol. C 2013, 133, 421–428, doi:10.1016/j.biortech.2013.01.141.
[49]
Jeffery, S.; Verheijen, F.G.A.; van der Velde, M.; Bastos, A.C. Quantitative review of the effects of biochar application to soils on crop productivity using meta-analysis. Agric. Ecosyst. Environ. 2011, 144, 175–187, doi:10.1016/j.agee.2011.08.015.
[50]
Haefele, S.M.; Konboon, Y.; Wongboon, W.; Amarante, S.; Maarifat, A.A.; Pfeiffer, E.M.; Knoblauch, C. Effects and fate of biochar from rice residues in rice-based systems. Field Crops Res. 2011, 121, 430–440, doi:10.1016/j.fcr.2011.01.014.
[51]
Verheijen, F.; Jeffery, S.; Bastos, A.C.; van der Velde, M.; Diafas, I. Biochar Application to Soils. A Critical Scientific Review of Effects on Soil Properties, Processes and Functions. JRC Scientific and Technical Reports; European Commission: Luxembourg, French, 2010. Available online: http://publications.jrc.ec.europa.eu/repository/bitstream/111111111/13558/1/jrc_biochar_soils.pdf (accessed on 05 November 2012).
Foereid, B.; Lehmann, J.; Major, J. Modeling black carbon degradation and movement in soil. Plant Soil 2011, 345, 223–236, doi:10.1007/s11104-011-0773-3.
[54]
Genesio, L.; Miglietta, F.; Lugato, E.; Baronti, S.; Pieri, M.; Vaccari, F.P. Surface albedo following biochar application in durum wheat. Environ. Res. Lett. 2012, 7, doi:10.1088/1748-9326/7/1/014025.
[55]
Meyers, S.; Bright, R.M.; Fischer, D.; Schulz, H.; Glaser, B. Glaser Albedo impact on the suitability of biochar systems to mitigate global warming. Environ. Sci. Technol. 2012, 46, 12726–12734, doi:10.1021/es302302g.
