生物质炭添加对杉木人工林土壤原有有机碳矿化的影响

通过培养试验,利用¹³C标记技术研究不同热解温度制备的生物质炭添加对杉木人工林土壤原有有机碳矿化的影响,为生物质资源有效利用和亚热带人工林固碳管理提供科学依据.生物质炭制备材料分别为木荷(阔叶树种)和杉木(针叶树种)凋落物,培养温度为25 ℃,时间为112 d.结果表明: 在整个培养阶段,与对照土壤相比,不同生物质炭添加对土壤原有有机碳矿化的影响均呈现先促进后抑制的规律,具体表现为杉木生物质炭处理仅在培养0～3 d表现为显著促进作用,在7～112 d均呈现为显著抑制作用,而木荷生物质炭处理则在培养0～14 d表现为促进作用,在28～112 d均表现为显著的抑制作用.培养结束时,3种杉木生物质炭(350、550和750 ℃)处理均显著抑制了土壤原有有机碳矿化,2种木荷生物质炭(350和550 ℃)处理也表现为显著的抑制作用.木荷生物质炭和杉木生物质炭的分解率介于0.8%～2.8%,随着热解温度的升高,生物质炭的分解率呈下降趋势,且同一热解温度下木荷生物质炭的分解率显著高于杉木生物质炭.上述结果表明,原材料和制备温度是生物质炭影响土壤原有有机碳矿化和生物质炭分解的重要因素.

Effects of biochar addition on the mineralization of native soil organic carbon in Cunninghamia lanceolata plantation.

Effects of addition of different biochars on soil organic carbon (SOC) mineralization were studied by the ¹³C-labelling technique for a better understanding of biomass resource utilization and carbon sequestration in subtropical Chinese fir (Cunninghamia lanceolata) plantation. An incubation experiment under 25 ℃ was performed over a period of 112 days to address how different biochar addition would affect the mineralization of native SOC. Biochars were produced from Schimasuperba or C. lanceolata litter at 350, 550 and 750 ℃, respectively. Results showed that the mineralization of native SOC was significantly accelerated during the first three days and subsequently suppressed from 7 to 112 days of incubation after C. lanceolata biochar addition compared to the control. In the S. superba biochar addition treatment, there was a significant increase in mineralization of native SOC within the first 14 days of incubation and then a rapid decrease from days 28 to 112. After 112 days incubation, all the three C. lanceolata biochar (350, 550 and 750 ℃) additions significantly inhibited the mineralization of native SOC. A similar trend was observed for the two S. superba biochar (350 and 550 ℃) additions but not for the S. superba biochar (750 ℃) addition. The decomposition rates of S. superba biochar and C. lanceolata biochar were 0.8%-2.8% after 112 days incubation and decreased with the increases of pyrolysis temperature. Under the same pyrolysis temperature, the decomposition rate of the S. superba biochar was significantly higher than that of the C. lanceolata biochar. In conclusion, both the raw material and pyrolysis temperature of biochars would be important factors driving the mineralization of native SOC and biochar degradation.