Clough, TimothyCondron, LKammann, CMüller, C2014-10-152013-04-162013-06Clough, T., Condron, L., Kammann, C., and Müller, C. (2013). A review of biochar and soil nitrogen dynamics. Agronomy, 3, 275-293. doi:10.3390/agronomy30202752073-4395V20DV (isidoc)https://hdl.handle.net/10182/6378Interest in biochar stems from its potential agronomic benefits and carbon sequestration ability. Biochar application alters soil nitrogen (N) dynamics. This review establishes emerging trends and gaps in biochar-N research. Biochar adsorption of NO₃⁻, up to 0.6 mg g⁻¹ biochar, occurs at pyrolysis temperatures >600 °C with amounts adsorbed dependent on feedstock and NO₃⁻ concentration. Biochar NH₄⁺ adsorption depends on feedstock, but no pyrolysis temperature trend is apparent. Long-term practical effectiveness of inorganic-N adsorption, as a NO₃⁻ leaching mitigation option, requires further study. Biochar adsorption of ammonia (NH₃) decreases NH₃ and NO₃⁻ losses during composting and after manure applications, and offers a mechanism for developing slow release fertilisers. Reductions in NH₃ loss vary with N source and biochar characteristics. Manure derived biochars have a role as N fertilizers. Increasing pyrolysis temperatures, during biochar manufacture from manures and biosolids, results in biochars with decreasing hydrolysable organic N and increasing aromatic and heterocyclic structures. The short- and long-term implications of biochar on N immobilisation and mineralization are specific to individual soil-biochar combinations and further systematic studies are required to predict agronomic and N cycling responses. Most nitrous oxide (N₂O) studies measuring nitrous oxide (N₂O) were short-term in nature and found emission reductions, but long-term studies are lacking, as is mechanistic understanding of reductions. Stable N isotopes have a role in elucidating biochar-N-soil dynamics. There remains a dearth of information regarding effects of biochar and soil biota on N cycling. Biochar has potential within agroecosystems to be an N input, and a mitigation agent for environmentally detrimental N losses. Future research needs to systematically understand biochar-N interactions over the long term.pp.275-293en© 2013 by the authors; licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution license (http://creativecommons.org/licenses/by/3.0/).biocharimmobilizationmineralizationnitrate leachingnitrogennitrous oxideammonia volatilisationJournal Article10.3390/agronomy30202752073-4395ANZSRC::3002 Agriculture, land and farm managementANZSRC::3004 Crop and pasture productionhttps://creativecommons.org/licenses/by/4.0/Attribution