亚高山暗针叶林的土壤呼吸

Soil Respiration of Subalpine Dark Coniferous Forests

以贡嘎山国家级自然保护区中峨眉冷杉(Abies fabri)林为研究对象,采用LI-6400-09便携式土壤呼吸室对其土壤呼吸速率进行了连续定位观测。结果表明:(1)峨眉冷杉成熟林和中龄林的土壤呼吸速率和土壤温度在各个月份存在差异;(2)两种林分的土壤呼吸速率具有明显的季节变化特征,表现为夏季>秋季>春季>冬季;成熟林的月平均土壤呼吸速率在0.82μmol·s^(-1)·m^(-2)～5.88μmol·s^(-1)·m^(-2)之间,季节变差系数为50.6%,中龄林的月平均土壤呼吸速率在0.52μmol·s^(-1)·m^(-2)～3.52μmol·s^(-1)·m^(-2)之间,季节变差系数为48.5%;(3)两种林分的土壤呼吸速率季节变化与土壤5 cm温度呈显著性正相关;(4)峨眉冷杉成熟林和中龄林土壤CO_2释放率的Q_(10)值分别为3.2和2.6,峨眉冷杉成熟林土壤呼吸对温度的敏感性指数要大于中龄林。

Field experiments were carried out to examine the soil respiration rate by LI-6400-09 portable soil respiration chamber in an Abies fabri forest in Gongga Mountain National Nature Reserve. The results showed that(1) the soil respiration rate and soil temperature were different in Abies fabri mature and half-mature forests each month;(2)The soil respiration rate of the two stands had obvious seasonal variation characteristics, which were arranged as: summer > autumn > spring > winter;the average monthly soil respiration rate of mature forest was between 0.82 μmol·s^-1·m^-2~ 5.88 μmol·s^-1·m^-2, the coefficient of seasonal variation was 50.6%, and the average monthly soil respiration rate of half-mature aged forest was between 0.52 μmol·s^-1·m^-2~3.52 μmol·s^-1·m^-2,the coefficient of seasonal variation was 48.5%;(3)The seasonal variation of soil respiration rate was positively correlated with the soil temperature of 5 cm;(4) The Q10 values of soil CO2 emission rates were 3.2 and 2.6 respectively in A. fabri mature and half-mature forest, the sensitivity index of soil respiration to temperature in mature A. fabri forest was higher than that in half-mature forest.