中文摘要：

为探讨不同类型黑碳和生物质炭中的不稳定碳含量及组分特征,以稻草田间堆烧和散烧残留黑碳和实验室内250,350,450,550,650℃下制备的生物质炭为研究对象,分析了水提取碳、重铬酸钾氧化碳和微生物矿化碳3种形式的不稳定碳含量,并对水提取物的红外光谱特征进行研究。水提取碳是指黑碳和生物质炭样品加纯水振荡8h并过0.45μm滤膜后的溶解态总碳;重铬酸钾氧化碳是指样品在55℃下被0.1mol/L K2Cr2O7∶2mol/L H2SO4（1∶1,v∶v）溶液氧化60h所去除的有机碳;微生物矿化碳是指样品加接种液培养一定时间后的累积矿化量。结果表明,黑碳和生物质炭中均含有一定量的水提取碳（3.01-16.52mg/g）、重铬酸钾氧化碳（10.28-94.62mg/g）和矿化碳（1.76-4.08mg/g）。水提取碳和重铬酸钾氧化碳在低温制备生物质炭中的含量总体上大于高温制备生物质炭和田间焚烧残留黑碳中的含量。重铬酸钾氧化碳与另2种不稳定碳之间均存在显著的正相关关系。3种黑碳和生物质炭在81d培养期内的累积矿化量与水提取碳含量在同一数量级;黑碳和生物质炭水提取物成分受制备温度的影响,主要官能团有羟基、羰基、醛基和羧酸根等,没有发现难降解的芳香成分,表明水提取碳是易于被微生物利用的组分。研究认为,高温制备生物质炭中的不稳定碳含量较低,适于固碳减排方面的应用;而低温制备的生物质炭有相对较高的不稳定碳含量,可能更适于保肥增产方面的应用。

英文摘要：

The residual black carbon（BC）from field burning of crop straw and the biochar made from agricultural waste are widely coming into agricultural soils.BC and biochar have been proven stable in soils due to their special physiochemical properties.However,they were reported recently to contain labile carbon components.So far,little is known about the contents and ingredients of labile carbon components in various types of BCs and biochars.This paper studied labile carbon components in residual BCs from field burning of rice straw in forms of spreading layers（BC1）and stacks（BC2）,and rice straw biochars produced under a range of temperatures,i.e.250,350,450,550,650 ℃（BC250,BC350,BC450,BC550 and BC650）.Three forms of labile carbon components were determined： Water-extractable carbon（WEC）,chemically dichromate-oxidized carbon（CrC）and biologically mineralized carbon（MC）.BC/biochar and deionised water（at a solid∶water ratio of1∶40,w∶w）were shaken together for 8hours.WEC was defined as the total carbon in the solution passing a0.45-μm filter.CrC was defined as the carbon loss after oxidation of BC/biochar with 0.1mol/L K2Cr2O7∶ 2mol/L H2SO4（1∶1,v∶v）at 55 ℃ for 60 hours.MC was the cumulative mineralization after an 81-day incubation expressed in terms of mg CO2-C/g BC（or biochar）.The Fourier transform infrared spectroscopy（FTIR）of water extract was also studied to reveal its constitution.The results showed that all three forms of labile carbon components were found in BC and biochar.WEC concentration was significantly higher in BC250（16.52mg/g）than in other BCs and biochars（3.01-7.42mg/g）.The higher the producing temperature was,the lower the WEC concentration in biochar was.The concentration of WEC in BC1 was significantly higher than that in BC2.The highest C-normalized WEC concentrations（6.13% -6.65%）were found in residual BCs due to lower total organic carbons（TOC）thereof.The value was 3.59%for BC250 and ranged from 0.53%to 0.78%for other bioc