小麦植株在麦田CH4交换中的作用及光照的影响
Effect of plant and light on CH4 exchange in the soil-plant system of wheat fields
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摘要: 采用密闭箱/气相色谱法对中国科学院山东禹城实验站的麦田CH4通量进行观测, 研究了土壤CH4通量、光照和遮光情况下的土壤-植物系统CH4通量, 及植物、光照等因素对CH4通量的影响。试验采用小暗箱测定土壤CH4通量, 采用暗箱和明箱测定土壤-植物系统CH4通量, 同步观测了生物量、5 cm土壤温度、土壤水分及土壤NH4+含量。结果表明, 麦田土壤和土壤-植物系统CH4通量均无明显的日变化, 但季节变化显著; 小麦的存在使土壤-植物系统CH4通量的季节波动加剧; 小麦植株和光照促进麦田土壤-植物系统对CH4的吸收。此外, 本研究发现在野外观测中, 采用明箱覆盖土壤以及植物进行观测更能真实反映有植被覆盖的地表CH4通量状况。Abstract: Methane (CH4) fluxes in wheat fields of the North China Plain were measured by closed chamber and GC techniques. The measured fluxes in the soil-plant systems through opaque chamber and transparent chamber were then compared. The results show obvious seasonal variations but insignificant diurnal variations in CH4 flux in the system. Wheat cover induces larger seasonal flux variation in the soil-plant system. Wheat and light increase soil-plant CH4 uptake. More importantly, however, transparent closed chamber proves the best CH4 flux measurement method in the field experiment.
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