长白山三种主要林地土壤甲烷通量

Soil methane fluxes of three forest types in Changbai Mountain of Northeast China

森林土壤甲烷(CH4)通量及主要影响因素的研究对于降低全球温室气体收支评估的不确定性具有重要价值。本研究通过室内培养实验,分析了土壤湿度、温度和氮添加对长白山3种主要林型(白桦林、山杨林和阔叶红松林)土壤甲烷通量的影响。结果表明:3种林型土壤均为甲烷汇,15d平均吸收速率分别为2.27μg·kg-1·h-1(山杨林)、1.54μg·kg-1·h-1(阔叶红松林)和1.46μg·kg-1·h-1(白桦林)。重复测量多元方差分析结果显示:林型、温度、土壤湿度及氮素处理对甲烷通量均有极显著影响(P<0.01),林型与其他因子交互作用显著;3种林型土壤甲烷吸收的最佳含水量为45%～60%;在10～20℃条件下,甲烷吸收速率随温度增加而增加;氮对甲烷吸收有明显抑制作用。

To study forest soil methane flux and its main affecting factors is of significance to re- duce the uncertainty of the evaluation of global greenhouse gases budget. In this paper, a labora- tory incubation experiment was conducted to study the effects of soil moisture, temperature, and nitrogen addition on the methane fluxes from the soils sampled from three typical forest types, i.e. , birch forest, poplar forest, and broad-leaved Korean pine forest, in Changbai Mountain. The results showed that the three forest soils were all the methane sink, and the average absorp- tion rates of methane in 15 days were 2.27 μg·kg^-1·h^-1（poplar forest）, 1.54 μg·kg^-1·h^-1 （broad-leaved Korean pine forest）, and 1.46 μg·kg^-1·h^-1（ birch forest）, respectively. The multivariate analysis of varianee（MANOVA） of repeated measurements showed that forest type, soil temperature, soil moisture, and nitrogen addition had significant effects （P 〈0.01 ） on the soil methane fluxes, and the interactive effects of forest type with other factors were signifieant. The optimum soil moisture eontent for soil methane absorption in three forests was 45%-60%. Under the condition of 10-20 ℃, the methane absorption rate increased with increasing tempera- ture. Nitrogen addition had significant inhibition effect on soil methane absorption.