A Review of Biochar and Soil Nitrogen Dynamics

Agronomy

Tim J. Clough²  Leo M. Condron²  Claudia Kammann¹ 

[1] Department of Plant Ecology, Heinrich-Buff-Ring 26-32 (IFZ), University Gießen, Germany; E-Mails:;Department of Soil and Physical Sciences, Faculty of Agriculture and Life Sciences, Lincoln University, Lincoln 7647, New Zealand; E-Mail:

关键词: biochar;    immobilization;    mineralization;    nitrate leaching;    nitrogen;    nitrous oxide;    ammonia volatilisation;   

DOI  :  10.3390/agronomy3020275

来源: mdpi

【 摘 要 】

Interest 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.

【 授权许可】

CC BY   
© 2013 by the authors; licensee MDPI, Basel, Switzerland.