催化氧化法与直接燃烧法测定土壤总碳之比较

Comparison of total soil carbon determination by catalytic oxidation method and direct combustion method

土壤碳库由有机碳库和无机碳库两大部分组成。选择黑土和潮土两种不同类型土壤,分别通过直接燃烧和催化氧化方法测定土壤总碳含量,以揭示两种方法测定结果的可比性及其差导显著性,每个样品每种方法重复测定5次。结果表明:催化氧化法和直接燃烧法测定的黑土总碳含量平均值分别为(15.10±0.03)g/kg和(15.38±0.32)g/kg,t检验两种方法的测定结果无明显差异。催化氧化法测定的潮土总碳含量为(15.07±0.06)g/kg,直接燃烧法测定潮土总碳含量为(15.76±0.18)g/kg,t检验结果差异明显。两种仪器土壤总碳测定结果精密度均较高,相对偏差均小于5%。为采用仪器方法测定土壤总碳含量及土壤碳库量变化提供参考。

Soil Carbon （ C） exists in both organic and inorganic forms. We compared the results of soil C values obtained by direct combustion method and catalytic combustions method. The black soil from Heilongjiang province in Northeast China and the calcareous fluvo-aquic soil from Shandong province in North China Plain were selected. The results showed that the C con-tents of black soil samples measured by the catalytic oxidation and the direct combustion method were （15. 10 ± 0. 03） g/kg and （15. 38 ± 0. 32） g/kg, respectively, with no significant difference according to t test. The C contents of fluvo-aquic soil samples were （15. 07 ± 0. 06） g /kg through catalytic oxidation method and （15. 76 ± 0. 18） g /kg by the direct com-bustion method and presented significant difference by t test. Both methods for soil C measurement had a high precision with relative standard deviation （ RSD） less than 5%. Compared with the catalytic oxidation method, the direct combustion meas-urement showed slightly higher levels of the standard deviation and the measurement uncertainty.