School of Resources, Environmental & Chemical Engineering and Key Laboratory of Poyang Lake Environment and Resource Utilization, Ministry of Education, Nanchang University, Nanchang 330031, China.
School of Land Resources and Environment, Jiangxi Agricultural University, Nanchang 330045, China.
Sci Total Environ. 2019 May 10;664:11-23. doi: 10.1016/j.scitotenv.2019.01.298. Epub 2019 Jan 24.
Biochar produced from pyrolysis of biomass is a candidate with great potential for climate change mitigation by carbon sequestration and reduction of greenhouse gases (GHG) emission in soil. Its potential depends considerably on biochar properties. Biochar stability or biochar C recalcitrance is decisive to its carbon storage/sequestration potential in soil. Three groups of methods including: I) biochar C structure or composition analyses, II) biochar oxidation resistance determination, and III) biochar persistence assessment by incubation & modelling, have been developed for evaluation of biochar stability. Amongst, incubation & modelling is the most commonly used one and is the basis of the other two assessment methods. However, the strategies for incubation experiment designing and data modelling significantly influence the biochar stability results. Drastic differences were observed for stability results obtained from different studies partly because of the large flexibility of the incubation & modelling method. Biased biochar stability would be obtained if the method was used improperly. The present review aims to provide comprehensive information on method strategies used for incubation and modelling, followed by discussions on the key issues such as what kind of biochar to use, how the experiment should be designed, how to determine biochar C mineralization, how the mineralization data should be expressed, and what model should be used, for an accurate biochar stability evaluation. In general, incubating biochar at long-term duration, modelling incubation data with double-exponential model, using C isotopic technology for CO evolution determination with C mineralization data express as percentage of total organic carbon mineralized, applying biochar in the field are favorable to biochar stability assessment. Other strategies such as the use of standard (reference) biochar materials may be effective to improve the assessment.
生物炭是通过生物质热解产生的，具有很大的潜力，可以通过固碳和减少土壤中的温室气体（GHG）排放来减缓气候变化。其潜力在很大程度上取决于生物炭的性质。生物炭的稳定性或生物炭 C 的抗降解性对其在土壤中的碳储存/封存潜力具有决定性意义。目前已经开发了三组方法来评估生物炭的稳定性，包括：I）生物炭 C 结构或组成分析，II）生物炭抗氧化性测定，以及 III）通过培养和建模评估生物炭的持久性。其中，培养和建模是最常用的方法，也是其他两种评估方法的基础。然而，培养实验设计和数据建模策略对生物炭稳定性结果有很大的影响。由于培养和建模方法的灵活性很大，不同研究获得的稳定性结果存在显著差异。如果方法使用不当，会得到有偏差的生物炭稳定性结果。本综述旨在提供有关培养和建模方法策略的全面信息，随后讨论了一些关键问题，例如使用哪种生物炭、如何设计实验、如何确定生物炭 C 矿化、如何表达矿化数据以及使用哪种模型进行准确的生物炭稳定性评估。一般来说，长期培养生物炭、用双指数模型对培养数据进行建模、使用 C 同位素技术测定 CO 释放并将矿化数据表示为总有机碳矿化的百分比、将生物炭应用于田间等有利于生物炭稳定性评估。其他策略，如使用标准（参考）生物炭材料，可能有助于提高评估的准确性。
