长白山典型森林土壤黑碳含量及不同组分中的分布特征

目的]通过实地采样对黑碳进行量化研究。方法]利用相对密度分组方法探讨了长白山典型森林土壤黑碳含量及在不同有机碳组分中的分布特征。结果]表明:黑碳(BC)含量在表层(A₁₁)、亚表层(A₁₂)分别为6.39~16.55 g·kg^-1、1.44~6.16 g·kg^-1,随土壤深度的增加而显著下降(p﹤0.01)。在A₁₁、A₁₂层中,轻组有机碳(LFOC)平均含量分别为66.66 g·kg^-1、6.65 g·kg^-1,轻组黑碳(LFBC)平均含量分别为5.63 g·kg^-1、1.21 g·kg^-1,同时,LFBC/LFOC在A₁₂层(10.02%~34.89%)显著高于A₁₁层(6.99%~14.45%)(p﹤0.01);A₁₁、A₁₂层重组有机碳(HFOC)平均含量分别为49.16 g·kg^-1、36.55 g·kg^-1,重组黑碳(HFBC)平均含量分别为2.69 g·kg^-1、1.44 g·kg^-1,HFBC/HFOC在A₁₁层(3.36%~8.08%)和A₁₂层(3.21%~7.58%)之间没有显著差异(p>0.05)。另外,土壤中LFBC/LFOC显著高于HFBC/HFOC(p﹤0.01),LFBC/BC显著高于HFBC/BC(p﹤0.01)。结论]长白山典型森林土壤中黑碳的含量、比例均较高;土壤表层(A₁₁)有机碳、黑碳含量及各组分有机碳、黑碳含量均高于亚表层(A₁₂),均随着土层加深而显著降低;轻组、重组有机碳中均含有一定比例的黑碳,黑碳主要分布在轻组分中;轻组、重组有机碳与组分中黑碳均显著相关,轻组中相关系数大于重组。

Content and Distribution of Black Carbon in Typical Forest Soils in Changbaishan Mountains

Black Carbon (BC) is an important component of the soil carbon pool and plays important roles in the long-term carbon sequestration because of its chemical stability. Even though black carbon directly affects the quantity and quality of soil organic carbon in forest soil, systematic few studies were conducted on the content and distribution of black carbon. The content and distribution of black carbon in typical forest soils in Changbaishan Mountains was investigated with relative density method. The results showed that the content of BC in surface soil layer (A₁₁) and sub-surface soil layer (A₁₂) were 6.39~16.55 and 1.44~6.16 g·kg^-1 respectively and the content decreased with the increase of soil depth (p<0.01). The average content of light-fraction organic carbon (LFOC) in A₁₁ and A₁₂ was 66.66 and 6.65 g·kg^-1 respectively; the average content of light-fraction black carbon (LFBC) was 5.63 g·kg^-1 in A₁₁ and 1.21 g·kg^-1 in A_12; the ratio of LFBC/LFOC in A₁₂ (10.02%~34.89%)was significantly higher than that in A₁₁ (6.99%~14.45%) (p<0.01). The average contents of heavy-fraction organic carbon (HFOC) in A₁₁ and A₁₂ were 49.16 and 36.55 g·kg^-1 respectively; the average content of heavy-fraction black carbon (HFBC) was 2.69 g·kg^-1 in A₁₁ and 1.44 g·kg^-1 in A₁₂; the ratio of HFBC/HFOC was 3.36%~8.08% in A₁₁ and 3.21%~7.58% in A₁₂ and the difference was not significant (p>0.05). In addition, the content of LFBC/LFOC was significantly higher than HFBC/HFOC (p<0.01) and LFBC/BC was significantly higher than HFBC/BC (p<0.01), suggesting that BC mainly was distributed in the light fraction. Furthermore, the LFOC and HFOC were significantly correlated with the contents of LFBC and HFBC respectively (p<0.01), and the coefficient of correlation was greater between LFOC and LFBC.