黔中非农业土壤CH_4的地-气交换及其影响因素

Fluxes of CH_4 from Non-Agricultural Soils in Central Guizhou Province and Their Affecting Factors

利用密闭箱-气相色谱法在2006-2007年对黔中地区退耕荒草地、灌丛、马尾松林和阔叶林土壤甲烷的交换通量进行原位观测。结果表明：亚热带喀斯特非农业土壤是大气CH4的一个吸收汇，相同植被条件下，淋溶石灰土吸收的CH4高于黄壤，而不同植被条件下土壤CH。的交换通量则因土壤类型的不同而有差异。土壤CH4交换通量的季节变化总体趋势表现为两个吸收峰，主要的吸收峰在温度较低的12月至次年2月，另一个较弱的吸收峰在7月至9月。统计分析表明，当温度〈10℃时，土壤温度是影响土壤CH4吸收的主要控制因素；温度〉10℃时，O～5cm的土壤水分成为控制土壤CH4吸收的主要因素。

Fluxes of CH4 from de-farming grasslands, bushes, pinus massoniana forests and hardwood forests which are located at central Guizhou were measured in si-tu using static closed chamber technique between 2006 and 2007. The results indicated that subtropical karst non-agricultural soils were the important sinks of atmospheric CH4. Under the same vegetation, CH4 fluxes from lime alfisol were lager than those from yellow soil. However, the fluxes of CH4 from soils under different vegetations varied with soil type. The general tendency of seasonal changes of CH4 fluxes showed two absorption bands, one from December to January and the other form July to September. The results of statistic analysis showed that soil temperature was the primary factor affecting CH4 fluxes from soils bellow 10℃, while soil moisture from 0 to 5 cm became the primary driving factor above 10℃.