生物碳的物理结构与化学成分对土壤氧化亚氮排放的影响

为探究生物碳对土壤中重要温室气体氧化亚氮(N2O)排放的影响机制,将生物碳的可溶性化学成分和稳定的物理结构分离后得到浸提液和碳骨架,设置了4种不同的实验处理方式:土壤(对照)、土壤+生物碳、土壤+浸提液、土壤+碳骨架,进行了为期90 d的室内培养试验.实验结果显示,在培养前期(前7 d),添加生物碳和碳骨架的处理都显著抑制了土壤N2O的释放,且抑制程度相似,最高均可达80%,而添加浸提液的处理却显著促进了土壤N2O的释放.因此,土壤添加生物碳后对N2O排放的抑制作用主要归因于生物碳的物理结构,生物碳的物理结构可以有效地提高土壤的pH值、吸附土壤及其自身含有的可能促进N2O释放的化学物质,从而减少土壤中N2O的产生和排放.

Effects of biochar's physical structure and chemical constituent on soil N2O emission

The aim of this study was to investigate the effects of biochar application on emission of an important greenhouse gas, nitrous oxide (N₂O), in the soil. The soluble chemical constituent and stable physical structure of biochar were separated into biochar-extracted liquid and carbon-skeleton. Four different treatments, i.e., soil only (the control), soil + biochar, soil + biochar-extracted liquid, and soil + carbon-skeleton, were established to carry out a 90-day incubation experiment. Results showed that the treatments of soil with biochar and carbon-skeleton significantly inhibited N₂O emission up to 80% in the early incubation period (within the first 7 days), while the treatment of soil with biochar-extracted liquid significantly stimulated the N₂O emission. It was concluded that the N₂O emission changes in the biochar treatments were mainly attributed to the biochar's physical structure. The biochar's physical structure can effectively increase soil pH and adsorb chemical constituents in the soil and biochar, which may stimulate N₂O emission and reduce N₂O production and emission.