NSW Department of Primary Industries, PO Box 100, Beecroft NSW 2119, Australia.
Environ Sci Technol. 2012 Nov 6;46(21):11770-8. doi: 10.1021/es302545b. Epub 2012 Oct 10.
The stability of biochar carbon (C) is the major determinant of its value for long-term C sequestration in soil. A long-term (5 year) laboratory experiment was conducted under controlled conditions using 11 biochars made from five C3 biomass feedstocks (Eucalyptus saligna wood and leaves, papermill sludge, poultry litter, cow manure) at 400 and/or 550 °C. The biochars were incubated in a vertisol containing organic C from a predominantly C4-vegetation source, and total CO(2)-C and associated δ(13)C were periodically measured. Between 0.5% and 8.9% of the biochar C was mineralized over 5 years. The C in manure-based biochars mineralized faster than that in plant-based biochars, and C in 400 °C biochars mineralized faster than that in corresponding 550 °C biochars. The estimated mean residence time (MRT) of C in biochars varied between 90 and 1600 years. These are conservative estimates because they represent MRT of relatively labile and intermediate-stability biochar C components. Furthermore, biochar C MRT is likely to be higher under field conditions of lower moisture, lower temperatures or nutrient availability constraints. Strong relationships of biochar C stability with the initial proportion of nonaromatic C and degree of aromatic C condensation in biochar support the use of these properties to predict biochar C stability in soil.
生物炭碳（C）的稳定性是其在土壤中进行长期碳封存的主要决定因素。本研究采用 5 种 C3 生物质原料（桉树的木材和叶片、纸浆厂污泥、家禽粪便、牛粪）在 400 和/或 550°C 下制备了 11 种生物炭，在控制条件下进行了为期 5 年的长期（5 年）实验室实验。生物炭在含有主要来源于 C4 植被源的有机碳的变性土中进行孵育，并定期测量总 CO2-C 和相关的 δ13C。在 5 年内，有 0.5%到 8.9%的生物炭 C 矿化。基于粪便的生物炭中的 C 比基于植物的生物炭中的 C 矿化更快，400°C 下制备的生物炭中的 C 比相应的 550°C 下制备的生物炭中的 C 矿化更快。生物炭中 C 的估计平均停留时间（MRT）在 90 到 1600 年之间变化。这些是保守估计，因为它们代表了相对不稳定和中等稳定性生物炭 C 成分的 MRT。此外，在水分、温度或养分供应限制较低的田间条件下，生物炭 C 的 MRT 可能更高。生物炭 C 稳定性与生物炭中非芳族 C 的初始比例和芳族 C 缩合程度之间的强关系支持使用这些特性来预测生物炭 C 在土壤中的稳定性。
