作 者 ：刘玲玲, 刘允芬, 温学发, 王迎红
期 刊 ：植物生态学报 2008年 32卷 2期 页码：431-439
Keywords:methaneflux, staticclosedchambertechnique, mid-subtropicalforestsoil, greenhousegas,
摘 要 ：CH4在温室效应中起着重要作用，为估算中亚热带CH4的源汇现状，评价森林生态系统对温室效应的影响，采用静态箱-气相色谱法研究了千烟洲红壤丘陵区人工针叶林的土壤CH4 排放通量特征及水热因子对其的影响。对2004年9月～2005年12月期间的观测结果分析表明 ：千烟洲人工针叶林土壤总体表现为大气CH4的吸收汇，原状林地土壤(Forest soil)情况下，CH4通量的变化为7.67～-67.17μg•m-2•h-1，平均为-15.53μg•m-2•h-1；无凋落物处理(Litter-free)情况下，CH4通量的变化是9.31～-90.36 μg•m-2•h-1，平均为-16.53μg•m-2•h-1。 二者对土壤CH4的吸收表现出明显的季节变化规律，秋>夏>冬>春，但无凋落物处理CH4变化幅度较原状林地土壤大，无凋落物处理吸收高峰出现在10月，最低值出现在翌年3月，原状林地土壤则分别在9月和翌年2月，均提前1个月。对土壤CH4吸收通量与温度和湿度的相关分析表明： 无论是原状林地土壤还是无凋落物处理情况下，土壤CH4通量都与地下5 cm的温度和湿度相关性最高。偏相关分析反映了不同季节水热配置对土壤吸收CH4通量的影响：冬季为12月～翌年2月，温度起主要作用；雨季3～6月，温度作用为主，随着温度的升高而升高，水分作用微弱；7～8月，CH4吸收通量随着湿度的降低而增加，但高温限制了CH4的吸收；秋季（9～11月）水热配置适宜，CH4通量达到高峰值。总之，CH4吸收通量随着温度的升高和 湿度的降低而增大，但温度过高会抑制其吸收。
Abstract:Aims Methane (CH4) plays an important role in the greenhouse effects. Our objectives were to evaluate the CH4 budget, understand seasonal variation of CH4, and explore effects of temperature and moisture on CH4 flux in a mid- subtropical pine plantation to provide data for estimating the influence of subtropical forest ecosystems on greenhouse effects.
Methods We analyzed CH4 flux from soils in the Qianyanzhou red earth hill region of China for 16 months from September 2004 to December 2005, using a static chamber-gas chromatograph technique.
Important findings The soil of this type of pine plantation was a sink of CH4 to the atmosphere as a whole; annual CH4 flux ranged from 7.67 to -67.μg•m-2•h-1 with average of -15.530 μg•m-2•h-1under a forest soil treatment and from 9.31 to -90.36μg•m-2•h-1 with average of -16.μg•m-2•h-1 under a litter-free treatment. CH4 absorption had similarly seasonal variations with a sequence of autumn > summer > spring > winter for both treatments, but differed in variation ranges and time. The litter-free soil had larger ranges of seasonal variations, maximum CH4 sink was in October and minimum sink was in March. Meanwhile , the corresponding maximum and minimum CH4 sinks in the forest soil were in the September and February, respectively, a month earlier than litter-free treatment. Analysis of correlations between CH4 flux and temperature and moisture showed that CH4 flux had a significant positive correlation to soil temperature at 5 cm depth and a significant negative correlation to soil water content at 5 cm depth. Partial correlations showed the combined effects of moisture and temperature on CH4 flux in different seasons. Temperature was a limiting factor for soil absorption of CH4 during winter (December to February), but soil absorption increased during the rainy season (March to May). From July to August, CH4 absorption increased with the declining soil moisture but was restricted by high temperature. During the fall (September to November), CH4 absorption reached the maximum value for suitable combined effects of temperature and moisture. In summary, CH4 absorption increased with soil temperature and decreased with soil water content, but was restricted by high temperature.
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