【作者】 叶丽丽；

【导师】 王翠红； 彭新华；

【作者基本信息】 湖南农业大学 ， 土壤学， 2011， 硕士

【摘要】 为了探讨黑炭(Biochar,简称BC)对土壤生物物理性质的影响,本研究通过室内恒温培养及盆栽试验相结合的方法,研究了不同焦化温度和时间对黑炭本身理化性质的影响,然后开展不同数量和质量的黑炭对红壤pH、CEC.土壤呼吸、团聚体稳定性、抗破碎性等性质的研究,并通过盆栽试验,揭示黑炭对玉米生长的影响。旨在为秸秆(Straw)焚烧还田提供科学依据。本研究主要结论包括以下三个部分：(1)黑炭物理化学性质黑炭的性质试验表明,黑炭的物理、化学性质受焦化温度和时间的影响很大。随温度升高(250℃到450℃)、时间延长(2到8小时),黑炭的回收率、挥发性物质的含量降低,其变化范围分别为26.0-63.2%,10.4-49.6%；而C、K、P、灰分含量升高,其变化幅度分别为57.2-72.9%,169-314 g kg-1,1.29-2.82 g kg-1；N的变化规律不够明显。电子显微镜扫描黑炭微结构表明,随温度、时间增加,黑炭碎裂程度加剧,其结构破坏更为严重。红外线光谱表明,温度或时间增加都会使黑炭中O、H及脂肪族C含量降低,而芳香族C含量增加。炭化时间与温度对黑炭性质的影响有相似的作用。(2)黑炭对土壤物理、化学及生物性质的影响室内恒温培养试验表明,在11天的室内恒温培养中(40%田间含水量,25℃),来源于5个炭化温度和3个炭化时间的黑炭对土壤累计呼吸速率有显著提高(P<0.05),较CK处理增加幅度达0.0065-0.046gg-1y-1,但通过55天的培养,黑炭对土壤呼吸的影响却不明显(P>0.05),可见黑炭对土壤呼吸的影响只是短时间。以碳矿化速率计算黑炭周转周期约为200-1700年,并随温度、时间增加呈增加趋势。而秸秆周转周期仅7年。施用黑炭显著提高了土壤pH、阳离子代换量(CEC) (P<0.05),其增加量分别为0.1-0.46,0.284-1.26cmol kg-1,但不能像秸秆一样提高土壤微生物C、N,团聚体水稳定性和土壤抗破碎性(P>0.05)。(3)黑炭对玉米生长的影响盆栽试验表明,在40天盆栽试验中,单施黑炭能提高玉米株高,但并未能提高作物生物量(P>0.05)。但在配施NPK情况下极显著提高玉米生长(P<0.001),玉米干重增加率在96.6-157%。不同温度、不同量的黑炭处理之间差异不显著。黑炭以肥料的形式对玉米生长贡献率为7%,而以调节剂的形式贡献率达到53%。更多还原

【Abstract】 Applying biochar to soils may cause a win-win situation resulting in C sequestration and soil fertility improvement. The effect may be more evident in highly weathered and infertile tropical soils, but will be dependent on biochar quality and amount. An Ultisol, typical to southern China, was used to evaluate amendment with biochars produced by a range of temperatures and durations, to investigate its effect on soil properties and plant growth. Rice straw-derived biochars were charred at temperatures from 250 to 450℃for between 2,4 and 8 hrs. Major conclusions were made below:(1) Characteristics of biocharsThe physical and chemical properties of biochars depend strongly on charring temperature and duration. The increase of charring temperature from 250 to 450℃and duration from 2 to 8 hrs decreased the yield of biochars from 63.2%to 26%, but increased C, K, P and ash content. The higher charring temperature further caused smaller less structured fragments as viewed by SEM, and form with less O, H and aliphatic C functional groups, but more aromatic C as indicated by infrared spectroscopy.(2) Effect of biochar amendment on soil biophysical propertiesDuring the 11-day incubation, the biochar amendment increased CO2 respiration as compared to control without biochar addition (P<0.05) but this effect disapeared with increasing incubation up to 55 days. The mean residence time (MRT) of biochars under controlled conditions (25℃,40% field capacity) was estimated from 200 to 1700 years, generally increasing with charring temperature and duration. But rice straw MRT was only 7 years. Amendment of 1%biochar increased pH by 0.1-0.46 (P< 0.01) and CEC by 3.9-17.3%(P< 0.05), but had no effect on microbial C and N (P< 0.05), aggregate stability (P> 0.05) and soil tensile strength (P> 0.05), disliking other organic materials (straw in this study).(3) Effect of biochar amendment on maize growthDuring the 40-day pot trials the biochar amendment did not significantly increase maize biomass (P> 0.05), but biochar plus NPK fertilizer increased biomass by 157% (P< 0.001). However, the biochar quality (as indicated by different charring temperatures) and amount (1% and 2%) did not have an effect on maize growth. This study further proved that the biochar as a fertilizer function only contributed to 7% of biomass, but as a conditioner accounted for 54% of biomass. The study emphasizes that amendment with biochar can improve soil fertility at least in the short term.更多还原