华北山地不同植被类型土壤呼吸特征研究

为准确揭示华北山地不同植被类型的土壤呼吸差异，该文利用LI-8100开路式土壤碳通量测量系统，于2006年6—8月测定并分析了太行山北段百花山区域5种典型植被类型的夏季土壤呼吸昼夜变化状况。结果显示，不同植被类型的土壤呼吸速率昼夜变化都表现为单峰曲线；农田和退耕地的土壤呼吸速率最高值、最低值以及日变化幅度都比天然灌木林、人工油松林和刺槐林的高；在全天CO2释放量方面，天然灌木林、人工油松林、人工刺槐林、退耕地和农田分别是5.44、6.28、6.27、7.71和10.92 g/(m2·d)；各样地的群落生物量、土壤有机碳含量、土壤5 cm处温度、近地面大气气压、湿度和CO2浓度等环境因子都对土壤呼吸速率具有明显的影响。不同植被类型土壤呼吸的分析结果表明，研究地自然状态下的天然灌木林土壤全天CO2释放量最低，人工针叶林和阔叶林略高出自然状态下的土壤，三者之间的差异较小；农田的释放量是自然状态下土壤的2倍以上，退耕行为和营造人工林有助于降低土壤CO2释放量。 

Soil respiration characteristics of different vegetation types in the mountain areas of north China.

In order to accurately explore the differences of different vegetation types in mountain land of northern China，diurnal variations of soil carbon flux of five typical vegetation types in Baihuashan Region，Taihang Mountainous Area were measured continuously in the summer of 2006 using LI-8100 automated soil CO₂ flux system. This study showed that the diurnal curves of soil respiration rate under different vegetation types had a simple peak value. The maximum，minimum and variation scope of cropland and abandoned sloping farmland were higher than those of natural brushwood，artificial Pinus tabulaeformis forests and Robinia pseudoacacia forests. Diurnal soil CO2 fluxes of natural brushwood，artificial P. tabulaeformis forests，artificial R. pseudoacacia forests，abandoned sloping farmland and cropland were 5.44，6.28，6.27，7.71 and 10.92 g/(m²·day). The relationship between soil respiration rate and environmental factors was extremely prominent. The results indicated that diurnal soil CO₂ flux of natural brushwood under natural state was the lowest among these five typical vegetation types，diurnal soil CO₂ fluxes of artificial P. tabulaeformis forests and R. pseudoacaciag forests were slight higher than that of brushwood，but there were no obvious differences among the above three types. Soil CO₂ flux of cropland surpassed over diploid of brushwood，so the behavior of turning cultivated land into forests and artificial forestations would be helpful to reduce soil CO₂ flux in the study area.