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利用稳定同位素13C技术,通过设置两种温度的恒温培养实验,研究了外源碳(13C-Glucose)在土壤中的分配规律、以及土壤有机碳(SOC)、轻组有机碳(LFOC)和重组有机碳(HFOC)的分解速率.培养温度分别为15℃和25℃,培养时间为112 d.结果表明:两个温度培养条件下,葡萄糖标记的13C进入SOC、LFOC和HFOC的比例随着培养时间而呈递减趋势,培养结束时标记的13C依然有18.9%~22.0%残留于土壤中.培养时段内,SOC的分解速率常数为4.4×10-4~9.7×10-4d-1,HFOC的分解速率常数为3.4×10-4~7.0×10-4d-1,而LFOC的分解速率常数介于1.1×10-3~4.6×10-3d-1之间.总之,外源碳显著影响了人工杉木林土壤有机碳组分的分解速率.在有外源碳输入的条件下,升温加快了LFOC的分解,但抑制了HFOC的分解.因此,在供试土壤中,LFOC可能会比HFOC对全球变暖的响应更敏感.
Stable isotope 13C was used to study the distribution of 13C-Glucose in soils and the effects of soil organic carbon (SOC), light organic carbon (LFOC) and recombination The decomposition rates of organic carbon (HFOC) were 15 ℃ and 25 ℃, respectively, and the incubation time was 112 d.The results showed that the ratio of glucose labeled 13C to SOC, LFOC and HFOC increased with the increase of culture temperature 13C remained at the end of culturing and remained at 18.9% ~ 22.0% in the soil during the incubation period.The decomposition rate constant of SOC was 4.4 × 10-4 ~ 9.7 × 10-4d-1 in the culture period, The decomposition rate constant is 3.4 × 10-4 ~ 7.0 × 10-4d-1, while the decomposition rate constant of LFOC is between 1.1 × 10-3 ~ 4.6 × 10-3d-1. In conclusion, the exogenous carbon significantly affects Under the condition of input of exogenous carbon, the temperature accelerated the decomposition of LFOC, but inhibited the decomposition of HFOC. Therefore, in the soil tested, LFOC may be higher than that of HFOC The response to global warming is more sensitive.