大兴安岭3种林分夏季土壤呼吸的日变化

Daily Variation of Soil Respiration in Three Typical Stands in Daxing'an Mountains in Summer

针对大兴安岭地区白桦林、杂木林和落叶松人工林3种林分,利用LI-8150碳通量自动测量系统测量3种林分夏季的土壤呼吸,分析土壤呼吸的日变化,建立土壤呼吸多因素回归模型。结果表明:3种林分的土壤呼吸日变化呈单峰趋势,土壤呼吸速率存在显著性差异。白桦林、杂木林和落叶松人工林的敏感指数(Q10)值分别为2.65、3.19和2.94。从回归方程得知,导致白桦林、杂木林、落叶松人工林土壤呼吸变化的主要因素,分别为土壤温度、土壤湿度和土壤有机质,说明在不同的生态系统中影响土壤呼吸的主要因素不同。

Soil respiration in summer was measured in birch forests, mixed forests, and larch planations in Daxing＇ an Mountains with LI-8150 carbon flux recorder. The daily variation of soil respiration was analyzed statistically, and a multivariate regression model was developed for soil respiration. Results showed that the changing tendency of soil respiration in all the forests could be described by a unimodal peak. Analysis of variance showed that there was a significant difference in soil respiration rate between the three forests. The sensitive indexes were 2.65, 3.19, and 2.94 for the birch forests, mixed forests, and larch planations, respectively. It is concluded that soil temperature, soil moisture, and soil organic content are the major factors affecting soil respiration in the birch forests, mixed forests, and larch planations, respectively. It indicates that the major factors affecting the soil respiration vary from ecosystem to ecosystem.