红壤丘陵区冬闲稻田CH4和N2O排放通量的研究

CH4和N2O是与全球气候变化密切相关的2种主要温室气体,其排放规律以及减排措施已成为当前研究的热点。休闲期抛荒稻田普遍存在于我国西南和南方地区,而对于其CH4和N2O排放规律的研究还比较少。本实验选取江西红壤丘陵区进行观测,于稻田休闲期采用静态箱-气相色谱法进行原位观测,旨在探讨休闲期CH4和N2O的排放规律,可为制定减排措施提供一定的依据。研究结果表明:红壤丘陵区冬闲稻田CH4和N2O平均排放通量(以CH4和N2O-N计)分别为0.03mg.m-2.h-1和3.27μg.m-2.h-1。冬闲期CH4和N2O平均排放通量与土温、降雨量无明显线性关系(P>0.05)。冬闲稻田排放CH4和N2O的综合温室效应(以CO2-eq计)为7.58 g.m-2,其中,CH4和N2O产生的温室效应(以CO2-eq计)分别为2.33和5.25 g.m-2。N2O排放量是冬闲稻田温室气体观测中不可忽视的部分。

CH4and N2O fluxes from winter fallow paddy fields in a hilly area of southeast China

CH4and N2O are two main greenhouse gases,which are closely related to global climate change.How to reduce their emissions has become a hot spot of the current research.Southwest and South China,it is quite common to have paddy fields kept in fallow in winter,but it is not to put under study CH4 and N2O regulations of the emission from these paddy fields.In this study,Yingtan in Jiangxi Province of China is selected as a site for in-situ observation of their emissions using.By the method of static opaque chamber/modified gas chromatograph,the results show that CH4 and N2O flux was 0.03 mgCH4.m-2.h-1and 3.27 μgN2O-N.m-2.h-1,respectively,in winter and had little to do with soil temperature at 5cm in depth and rainfall.The overall GWP of CH4 and N2O emitted from the winter fallow paddy fields was 7.58 gCO2-eq.m-2,to which CH4 and N2O contributed 2.33 gCO2-eq.m-2and 5.25 gCO2-eq.m-2,respectively.The findings demonstrate that the N2O emission from winter fallow paddy fields is so important in GWP that it cannot be ignored.