摘要
稻田生态系统中CH_4排放是由土壤中CH_4产生、氧化和向大气传输这3个过程相互作用的结果,CH_4传输主要通过液相扩散、冒气泡和植株传输3种方式。这3种途径的相对强弱取决于水稻植株通气组织的完善与否以及水稻品种、种植密度和温度的季节变化等。但大量研究表明,稻田土壤中产生的CH_4绝大部分通过植株通气组织排放到大气中。在应用稳定性碳同位素方法研究水稻植株向大气传输CH_4的过程时发现,在传输过程也会发生同位素分馏,据现有文献报道,CH_4传输的同位素分馏系数ε_(传输)有两种计算方法,获得的结果也比较接近,为-18‰～-9‰。但研究方法还存在一些缺陷,可能对结果的准确性产生影响。此外有关稻田CH_4传输在模型的建立方面还比较缺乏。
CH4 emission is an interaction result of CH4 production,oxidation and transport in rice paddy field.CH4 emits into the atmosphere primarily through the following three channels：liquid diffusion,bubble and plant aerenchyma.The relative contributions of the three pathways to CH4 emission varies according to organic loading,rice cultivar,rice planting density,seasonal variation in temperature,etc.A large number of researches indicated that CH4 generated in paddy soils mostly emitted into the atmosphere through the aerenchyma of rice plants.The application of stable carbon isotope technique to investigate CH4 transport through the aerenchyma of rice plants found that isotope fractionation existed in the process of CH4 transport.It is reported that there are two ways to calculate isotope fractionation factorε（transport） of CH4 transport,and the results obtained in the two ways（-18‰～-9‰） are quite approximate.But previous research methods have some defects,which may affect the accuracy of the results.Furthermore there lacks of model about CH4 transport in paddy soil.
出处
《土壤》
CAS
CSCD
北大核心
2012年第2期181-187,共7页
Soils
基金
国家自然科学基金项目(41071169)
中国科学院战略性先导科技专项(XDA05020200)
科技部国际科技合作项目(S2012GR0080)资助
