生物炭添加对盐渍土CT孔隙序列分形特征来源的影响

为了揭示生物炭改良土壤孔隙的复杂结构及其影响因素,以江苏滨海盐渍土为研究对象,采用添加生物炭改良盐渍土,设置0,2%,5%(占表层0—20 cm土重比)3个生物炭添加水平。每年10月在水稻收割后,采用塑料环刀取表层(0—20 cm)原状土,进行Micro-CT扫描获取土壤CT孔隙序列。基于多重分形去趋势波动分析理论,并结合数据重排,分析施加生物炭对CT孔隙序列多重分形特征及其来源的影响。结果表明,所有处理的CT孔隙序列的复杂度均随着年份增长;2%生物炭处理的CT孔隙序列的复杂程度较0和5%生物炭处理分别提高7.54%和5.28%;概率密度函数与长程相关性均影响CT孔隙序列的多重分形特征;孔隙和空间的长程相关性是主要影响因素;生物炭的添加促使孔隙分形特征更易受到土壤中生物微生物活动的影响。研究结果为定量化分析生物炭改良盐渍土孔隙结构提供了理论支持。

Effect of Biochar Addition on the Fractality Source of CT Porosity Series in Saline Soil

In order to reveal the pores complex structure of biochar-amended soils and its influencing factors, the saline/sodic soil in the coastal reclamation area of Jiangsu Province was taken as the research subject. In this study, the surface soils (0-20 cm) were amended by thoroughly mixed biochar with three application rates (0, 2% and 5% by mass of soil, respectively) in a completely randomized design. After harvesting rice in October each year, the surface layer (0-20 cm) of undisturbed soils was taken using a plastic ring and the CT pore series of the soil was obtained through Micro-CT scanning. Based on multifractal detrended fluctuation analysis and data rearrangement, the influence of biochar addition on the multifractal characteristics and their source of CT-porosity series was analyzed. The results showed that the complexity of pore series for each treatment increased with year. Compared with 0 and 5% biochar treatments, the complexity of CT pore series in 2% biochar treatments increased by 7.54% and 5.28%, respectively. Both probability density function and long-range correlation influenced the multifractal characteristics of CT pore series. Long-range correlation between pore and space was the main influencing factor. The addition of biochar made the pore fractal characteristics more susceptible to the influence of microbial activities in soil. This study could provide a theoretical basis for analyzing the pore structure of saline soil with biochar.