黔中土壤CO2的释放特征及其影响因素

Fluxes of CO_2 from soils in central of Guizhou province and its controlling 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、阔叶林土壤二氧化碳的释放通量进行原位观测。结果表明,各观测点均为CO2的源,释放通量介于C(119.2±62.0)^(199.7±72.2)mg·m-2·h-1,植被条件和土壤类型影响土壤CO2的释放通量。相同植被条件下,黄壤释放的CO2高于石灰土土壤。不同植被条件下,黄壤CO2的释放具有相同的季节变化规律,夏季最高而冬季最低,年均释放量按林地、灌丛、退耕荒草地的顺序递减;石灰土CO2的释放季节变化规律则差异较大,年均释放量按灌丛、林地、退耕荒草地顺序递减。相关性分析表明,温度和土壤水分对土壤CO2释放通量的影响在不同观测点表现不同,总体表现为对黄壤的影响要比石灰土明显。

Fluxes of CO2 from de-farming grassland soils, bush soils, pinus massoniana forest soils, and hardwood forest soils in central of Guizhou were measured in situ using static close chamber-GC method between 2006 and 2007. The results indicated that all the observation sites were the sources of CO2, and the ranges of fluxes were from （119.2±62.0） to （199.7±72.2） mg·C·m^-2·h-1, Vegetations and soil types had important effects on CO2 fluxes. The fluxes from yellow soils were higher than that form lime soils under the same vegetation. Under different vegetations, The seasonal variability of CO2 fluxes from yellow soils was uniform, higher in summer and lower in winter, and the mean total annual fluxes decreased in the order of forest, bush, de-farming grassland, while from lime soil were irrelevant, the mean total annual fluxes decreased with the rank of bush, forest, de-fanning grassland. The results of correlation analysis showed that the effects of temperature and soil moisture on CO2 fluxes vary from different sites and the effects were more obvious in yellow soils than in lime soils.