鼎湖山针阔叶混交林地表CH_4通量

CH_4 fluxes from soil of coniferous broad-leaved mixed forest in Dinghu Mountain

用静态箱-气相色谱法对鼎湖山针阔叶混交林的地表CH4通量进行了为期一年的原位观测和研究。结果表明,该林型土壤总体为大气CH4的吸收汇,通量年变化范围60～-120μg·m-2·h-1,在雨季向旱季过渡的9、10月份,土壤对CH4的吸收较为强烈,而在冬季的1月份,吸收通量最小;凋落物层对该林型地表CH4的吸收没有明显的阻隔作用;多元回归分析发现CH4通量与地下5cm温度显著相关,尤其是在土壤湿度变化不大的旱季,土壤表层温度为影响CH4通量的主导因子。

In situ CH4 flux from soil of coniferous and broad-leaved mixed forest in Dinghushan Biosphere Reserve was measured for one year by using static chamber-gas chromatograph technique. The results are given as follows: The soil of this type of forest was the sink of CH4 to the atmosphere as a whole, but was the source of CH4 occasionally in rainy season, the annual CH4 flux ranged from 60 to –120 μg·m-2·h-1 with average of -44.60±5.79 μg·m-2·h-1. Strong CH4 sink appeared at the end of rainy season and the start of dry season, weak CH4 sink appeared in winter. Litter layer had no distinct impact on CH4 uptake by soil. CH4 flux was significantly correlated with soil temperature at 5 cm depth, especially during dry season when the soil moisture was rather stable.