Shrinkage Characteristics of Lime Concretion Black Soil as Affected by Biochar Amendment
Shrinkage Characteristics of Lime Concretion Black Soil as Affected by Biochar Amendment
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DOI：
10.1016/s1002-0160(18)60041-4
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发表时间：
2018-10-01
期刊：
影响因子：
5.7
通讯作者：
Li Baoguo
中科院分区：
文献类型：
--
作者：
Wei Cuilan;Gao Weida;Li Baoguo
研究报告指出，生物炭是一种可持续的改良剂，可改善土壤的化学和物理性质。通过室内培养试验，研究了不同生物炭施用量对砂姜黑土经3次干湿循环后的开裂形态和收缩特性的影响。将来自玉米秸秆和花生壳混合物的生物炭以0、50、100和150 g kg（-1）干重的比率施用到土壤中，分别代表处理T-0、T-50、T-100和T-150。在湿润和干燥循环过程中，记录了未改良和改良土样的开裂模式和收缩特性。施用生物炭显著提高了土壤有机碳含量。在土壤干燥过程中，生物炭显著降低了水分流失速率。由于施用生物炭的土壤中相对较高的含水量，裂缝缓慢扩展并停止。随着生物质炭施用量的增加，干燥过程中的裂纹面密度（rho c）、等效宽度、分形维数和裂纹连通性指数逐渐减小。T-50、T-100和T-150处理的rho c值在三个湿润和干燥循环后分别下降了33.6%、52.1%和56.9%，而To处理表现出轻微的变化。线性延伸系数，一个用来描述一维收缩的指数，未经修改的土样（T-0）约为0.23。施用100和150 g kg（-1）生物炭显著降低了土壤的收缩能力，分别降低了41.45%和45.54%。随着生物炭施用量的增加，表征土壤孔隙比与含水率关系的收缩特性曲线的斜率逐渐减小。此外，与To处理相比，T-50、T-100和T-150处理的收缩特性曲线的比例收缩区分别减小5.8%、13.1%和12.1%。各处理间收缩特性曲线最大曲率处的含水率无差异。结果表明，生物炭能够改变砂姜黑土的开裂模式和收缩特性。然而，生物炭对砂姜黑土收缩的影响取决于干湿循环次数。
Studies have reported that biochar is a sustainable amendment that improves the chemical and physical properties of soil. In this study, an incubation experiment was conducted to investigate the effects of different application rates of biochar on the cracking pattern and shrinkage characteristics of lime concretion black soil after three wetting and drying cycles. Biochar derived from the corn straw and peanut shell mixture was applied to the soil at rates of 0, 50, 100, and 150 g kg(-1) dry weight, representing the treatments T-0, T-50, T-100, and T-150, respectively. During the wetting and drying cycles, the cracking pattern and shrinkage characteristics of the unamended and amended soil samples were recorded. Application of biochar significantly increased soil organic carbon content in the samples. During soil desiccation, biochar significantly reduced the rate of water loss. Cracks propagated slowly and stopped due to the relatively higher water content in the soil applied with biochar. The cracking area density (rho c), equivalent width, fractal dimension, and cracking connectivity index decreased during the drying process with increasing application rate of biochar. The rho c value of the T-50, T-100, and T-150 treatments decreased by 33.6%, 52.1%, and 56.9%, respectively, after three wetting and drying cycles, whereas the To treatment exhibited a marginal change. The coefficient of linear extensibility, an index used to describe onedimentional shrinkage, of the unamended soil sample (T-0) was approximately 0.23. Application of 100 and 150 g kg(-1) biochar to the soil significantly reduced the shrinkage capacity by 41.45% and 45.54%, respectively. The slope of the shrinkage characteristics curve, which indicates the ralationship between soil void ratio and moisture ratio, decreased with increase in the application rate of biochar. Furthermore, compared with the To treatment, the proportional shrinkage zone of the shrinkage characteristic curve of the T-50, T-100, and T-150 treatments decreased by 5.8%, 13.1%, and 12.1%, respectively. Differences were not observed in the moisture ratio at the maximum curvature of the shrinkage characteristic curve among the treatments. The results indicate that biochar can alter the cracking pattern and shrinkage characteristics of lime concretion black soil. However, the effects of biochar on the shrinkage of lime concretion black soil are dependent on the number of wetting and drying cycles.