荒漠土壤微生物碳垂直分布规律对有机碳库的表征作用

以古尔班通古特沙漠南缘原始盐漠为研究对象,测定不同深度的土壤有机碳和土壤微生物碳含量,以分析它们之间的响应关系。结果表明:(1)在土壤垂直剖面上,土壤微生物碳（SMC）含量与有机碳（SOC）含量呈现极显著正线性相关（R2=0.63,p=0.0003）。（2）SMC出现了2个明显的改变界面（20 cm,80 cm）,0~20、20~80、80~500 cm值分别为:2.24~3.06、0.19~0.72、0.0017~0.0097 mg·kg-1;0~20 cm和20~80 cm的SMC差异极显著（p<0.0001）,20~80 cm和80~500 cm的SMC差异显著（p<0.05）。（3）对应于SMC的土壤层划分,SOC在0~20 cm、20~80 cm和80~500 cm同样具有一定的分层性。（4）我们把具有不同微生物活性的有机碳层分别定义为活性、惰性、稳定性有机碳库,土壤垂直剖面上微生物碳的分布很好地表征了土壤中活性、惰性、稳定性有机碳库的分布;通过对这3种碳库所在土层进行合理划分,可以定量分析土壤中3种有机碳库的储量。

Desert Soil Organic Carbon Characterized by the Vertical Distribution of Soil Microbial Carbon

The goal of the present research was to analyze the response relation of soil organic carbon （SOC）to soil microbial carbon （SMC） at different depths of original salt desert in the southern boundary of the Garbantunggut Desert. The results showed that: In the soil vertical profile, SMC and SOC presented a significant positive linear correlation (R2=0.63, p=0.0003). SMC exhibited two obvious changed-interfaces, 20 cm and 80 cm, the SMC at the depth of 0-20 cm, 20-80 cm and 80-500 cm was 2.24-3.06, 0.19-0.72, and 0.0017-0.0097 mg\5kg-1 , respectively; the SMC at 0-20 cm and 20-80 cm were significant different (p<0.0001), that at 20-80 cm and 80-500 cm were also significant different (p=0.013). Corresponding to the soil division based on SMC, the SOC also had some certain stratification. We defined organic carbon layers with different microbial activity as active, inert, and stable organic carbon library. The soil microbial carbon in the vertical profile presented a good characterization of the distribution of the active, inert, and stable organic carbon library. Therefore, these three kinds of organic carbon library can be quantified by reasonable analyzing their locations at different depths of soil vertical profile.