生物质炭对连作参地土壤肥力及微生物特性的影响

为分析生物质炭用于老参地土壤修复的可行性,本研究采用Biolog、高通量测序等技术研究了3种生物质炭对连作参地人参品质、土壤肥力、微生物群落结构与功能多样性变化的影响。结果显示,增施不同生物质炭均有助于两年生重茬人参生物量及总皂苷含量的积累。结合生物质炭对土壤性质的影响研究结果发现,不同生物质炭对土壤有效磷、有机碳含量具有稳定的提升效果,增幅分别为47.04%~237.73%、8.09%~38.71%。增施生物质炭促进了土壤微生物的代谢活性,增加了土壤对聚合物类、酚酸类、氨基酸类、羧酸类碳源的利用效率,其中以酚酸类物质为底物的功能微生物种群数量显著增加。高通量测序结果显示,老参地土壤细菌物种数、丰度与多样性均呈下降趋势,细菌优势门类减少,单个门类优势度上升。生物质炭处理下土壤中细菌丰度与多样性增加,调控了变形菌门、厚壁菌门、疣微菌门、芽单胞菌门的优势度,使其数量变化趋势趋向于新林土。上述分析表明,重茬人参生物量和品质的提高与生物质炭提升土壤中人参生长的关键肥力指标,促进微生物代谢,调控细菌群落结构变化趋势有关。综上,生物质炭对老参地土壤表现出良好的修复、改良作用,适量增施生物质炭有利于老参地土壤质量的调节与恢复。

Effect of Biochar on Soil Fertility and Microbial Properties in Continuous Cropping Ginseng Field

The effects of biochar on quality of ginseng, soil fertility, microbial community structure and functional diversity of microbiota in continuous cropping ginseng fields were studied by Biolog, high-throughput sequencing and other technologies, to analysis whether biochar has the potential of biostimulation for remediaton of such soil. The results showed that biochar treatment significantly improved total ginsenoside contents and biomass of two-year-old replanting ginseng compared with the control. To uncover the reasons for the increase, soil properties were examined and it was found that available phosphorus and organic carbon content in the soil responded positively to the addition of biochars with increase rate of 47.04%~237.73% and 8.09%~38.71%. Treatments with different biochars also potentiated the metabolic activity of soil microorganisms, specified by the utilization efficiency of carbon sources including polymers, phenolic acids, amino acids, and carboxylic acid. The number of functional microorganisms which use phenolic acids as substrates also showed a remarkable increase. High-throughput sequencing revealed that while the dominance of single category showed an increase, the species number, abundance and diversity of bacterial species, the dominant bacteria category displayed a reduction in the ginseng-grown land. Application of biochar into soil regulated the deteriorating tendency, the abundance of bacteria increased and dynamic quantity trend of the Proteobacteria, Firmicutes, Verrucomicrobia, and Blastomonas was similar with the changes in forest soil. These findings indicate that biochar resulted in better soil quality and increased productivity in replanting ginseng soil, especially in the key fertility factors, microbial metabolism and bacterial community structure. Thus, biochar performed well in this soil remediation and might be considered a novel approach for continuous cropping ginseng field.