关键词：
生物质炭;热解温度;呼吸速率;微生物量碳;半衰期
摘 要：
以苹果树修剪的枝条为原料,分别在300、400、500、600℃条件下热解制备生物质炭,在采用扫描电镜、红外光谱、物理化学吸附仪等手段研究其性质、结构差异的基础上,通过培养试验研究不同温度制备生物质炭的矿化特征及其对土壤有机碳组分的影响。结果表明,随着热解温度的升高,生物质炭的碳含量、比表面积及碱性官能团的含量增加,O、H及H/C、O/C和酸性官能团、总官能团的含量则降低,生物质炭的芳香族结构加强,稳定性升高。添加生物质炭可以增加土壤呼吸速率、微生物量碳(MBC)及可溶性有机碳(DOC)的含量,且随着添加比例的增加而增加,但随着热解温度的升高而降低。生物质炭的矿化率随着热解温度升高和添加比例增加而降低。利用双库模型揭示了生物质炭对土壤活性碳库、惰性碳库及其分解速率的影响。施用生物质炭后土壤有机碳的半衰期在24.09~44.76 a之间,且随生物质炭制备温度升高而增大。考虑到生物质炭制备过程中有机碳的损失,且从提升土壤有机碳含量方面考虑,500℃为制备苹果枝条生物质炭的最佳温度。
译 名：
Characteristics and Mineralization in Soil of Apple-derived Biochar Producecd at Different Temperatures
作 者：
Zhao Shixiang;Ji Qiang;Li Zhonghui;Wang Xudong;College of Natural Resources and Environment,Northwest A&F University;Key Laboratory of Plant Nutrition and Agri-environment in Northwest China,Ministry of Agriculture;
关键词：
Biochar Pyrolysis temperature Respiration rate Microbial biomass carbon Half-life
摘 要：
The aim of this study was to investigate the influence of pyrolysis temperature on the physicochemical properties of biochar,and the effect of biochar addition on carbon contents of soil organic matter fractions and carbon mineralization characteristics. Biochars were produced by fast pyrolysis of apple tree twigs at 300,400,500 and 600℃,respectively. Characterizations of biochars were determined by elemental analysis,Brunauer-Emmett-Teller( BET) for surface area,scanning electron microscopy( SEM),Fourier transform infrared( FTIR) spectroscopy. Four kinds of biochar were added to soils at five application rates as soil only( control),soil + 0. 5% biochar,soil + 1% biochar,soil + 2% biochar and soil + 3% biochar,which were incubated at 25℃ in lab. Carbon mineralization was analyzed by alkali absorption of CO2 released periodically over 180 d. Soil samples were analyzed for microbial biomass carbon( MBC) and soil dissolved organic carbon( DOC). The results showed that the generated biochars contained 62. 20% ~ 80. 01% of carbon( C),2. 72% ~ 5. 18% of hydrogen( H) and 15. 99% ~30. 94% of oxygen( O). The BET surface area was 2. 35 ~ 107. 76 m2/ g,basic functional groups were0. 11 ~ 0. 40 mmol / g and acidic functional groups were 0. 44 ~ 1. 16 mmol / g. The increasing temperature( from 300℃ to 600℃) increased biochar C content,BET surface area and basic functional groups,whiledecreased the content of O and H,H / C and O / C ratio,acidic functional groups and total functional groups. Soil respiration,MBC and DOC were increased by biochar application. As pyrolysis temperature increased and biochar application rate decreased,soil respiration,MBC and DOC decreased in all soils.The mineralization of biochar C decreased significantly( P < 0. 05) from 7. 86% to 0. 60% when pyrolysis temperature increased from 300℃ to 600℃. A double-exponential equation was used to describe C mineralization kinetics and curve fitting was performed to mathematically define the size and turnover rate of two C source pools( labile and stable). The size of labile pool( A1) varied from 0. 31 g/kg to 0. 94 g / kg,while the size of stable pool( A2) varied from 6. 88 g /kg to 30. 82 g /kg. The decreased mineralization rates of the labile and stable pools( k1 and k2) were resulted from the increased pyrolysis temperature and the decreased biochar application rates. Half-life of C in soil varied between 24. 09 a and44. 76 a and increased with the increase of pyrolysis temperature and biochar application rates.Conclusively,pyrolysis temperature had important effect on the physico-chemical properties of biochar and therefore resulting in different stabilities of soil organic matter. Considering the carbon loss in the process of preparing biochar,500℃ would be the optimal temperature for preparing apple-derived biochar due to the most significant promotion of soil organic carbon.
