| 不同温度制备的生物质炭对土壤有机碳及其组分的影响:对土壤腐殖物质组成及性质的影响 |
| 摘要点击 2058 全文点击 856 投稿时间：2016-04-08 修订日期：2016-08-10 |
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| 中文关键词 生物质炭 腐殖物质 富里酸 胡敏酸 胡敏素 色调系数 |
| 英文关键词 biochar humic substances fulvic acids humic acids humin color tonal coefficient |
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| 中文摘要 |
| 添加生物质炭在增加土壤固碳的同时，对土壤腐殖物质组成及性质的影响是人们关注的问题.通过室内培养试验对土壤腐殖物质进行提取和分离，利用分光光度计测定了土壤胡敏酸（HA）及富里酸（FA）的光学性质，研究了不同热解温度及施用量下生物质炭对土壤腐殖物质组成及结构的影响.结果表明：生物质炭中的类腐殖酸（LHS）含量随热解温度升高逐渐降低，但其结构趋向复杂化.与对照相比，低温（≤400℃）制备的生物质炭在培养期间增加了土壤HA含量，并随着添加比例的增加而增加，培养360 d后，BC300和BC400处理平均分别增加了69.93%和48.75%，且差异达到显著水平（P<0.05）；FA含量在培养前期（240 d）也有所增加，但后期减少了土壤FA含量，培养360 d后，BC300和BC400处理平均分别减少了1.35%和5.19%，但差异并不显著（P<0.05）；高温（>400℃）制备的生物质炭在培养过程中主要降低了土壤HA和FA含量（仅在培养初期阶段引起土壤HA、FA含量的短时间增加），至培养结束时，BC500处理平均分别减少了34.38%和44.48%，BC600处理平均分别减少了42.84%和49.27%，且差异均达到显著水平（P<0.05）.生物质炭输入显著增加了土壤胡敏素（Hu）的含量，其中以BC500处理的增加效应最大.生物质炭输入增加了土壤H/F比，提高了土壤Hu的相对含量，增加了土壤中相对稳定性碳的比例.高温制备（>400℃）的生物质炭培养结束时显著降低了土壤HA及FA的色调系数（ΔlgK）和E4/E6值，使土壤腐殖物质的结构复杂化，而低温制备的则相反.从提升有机碳的稳定性考虑，在黄土高原塿土地区，在500℃条件下制备生物质炭，既能保证最大程度的增加土壤稳定性有机碳库，又提高了土壤腐殖化程度，从而提高土壤质量. |
| 英文摘要 |
| Application of biochar (BC) is an important way to increase soil organic carbon sequestration. At the same time, the effect of BC on fractions and properties of soil humic substances is concerned. A laboratory experiment was conducted to study the influences of BC pyrolyzed at different temperatures on the composition and properties of humic substances. The modified method for the extraction and fractionation of humic substances was adopted in this work. The carbon (C) contents of Humin (Hu), Humic acids (HA), Fulvic acids (FA) were analyzed by the thermal oxidation of K2Cr2O7 and TOC analyzer, and the optical properties of HA and FA were measured by using spectrophotometer. The results showed that the increasing temperature (from 300 to 600℃) decreased like-humic substances (LHS) from 10.93 g·kg-1 to 0.26 g·kg-1, while the structure of theLHS tended to be complicated. Compared with control treatment (CK), the addition of BC produced under 400℃ increased the contents of HA and FA (after 240 d incubation a lower FA content was found in treatments) and increased as BC application rate increased, after 360 d of incubation, BC300 and BC400 significantly increased by 69.93% and 48.75% for HA (P<0.05), while decreased by 1.35% and 5.19% for FA. Higher contents of HA and FA were found in soil samples amended with BC prepared at above 400℃ only during the initial period of 3-10 d of incubation and increased as BC application rate increased, at the end of the incubation, the contents of HA and FA significantly decreased by 34.38%, 44.48% in BC500 treatments and 42.84%, 49.27% in the BC600 treatments (P<0.05). During the incubation, the addition of BC significantly increased the contents of Hu (P<0.05), and the treatments amended with BC500 were the highest. The addition of BC decreased the relative contents of HA and FA, while increased the relative content of Hu, indicating that the proportion of relatively stable organic carbon in the soil was increased. The ratio of HA/FA (H/F) varied between 0.88 and 2.52 and increased with decreasing pyrolysis temperature and increasing BC application. A significantly lower color tonal coefficient (ΔlgK) and E4/E6 values in treatments amended with BC produced at temperatures above 400℃, indicating that higher temperatures derived BC complicated the structure of soil humic substance, while an opposite rend was observed in treatments amended with BC produced at temperatures under 400℃. Considering the improvement of the stability of organic carbon, when the BC products were applied to the Loutu soil, 500℃ was the optimal temperature for preparing apple-derived BC not only because it could significantly increase the content of inert soil organic carbon, but also improve the quality of the soil as a result of enhancing the degree of soil humification. |
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